Role of N-acetylkynurenine in mediating the effect of gut microbiota on urinary tract infection: a Mendelian randomization study.

Introduction: This study explored the causal connections between gut microbiota (GM), urinary tract infection (UTI), and potential metabolite mediators using Mendelian randomization (MR). Methods: We utilized summary statistics from the most comprehensive and extensive genome-wide association studies (GWAS) available to date, including 196 bacterial traits for GM, 1,091 blood metabolites, 309 metabolite ratios, alongside UTI data from ukb-b-8814 and ebi-a-GCST90013890. Bidirectional MR analyses were conducted to investigate the causal links between GM and UTI. Subsequently, two MR analyses were performed to identify the potential mediating metabolites, followed by a two-step MR analysis to quantify the mediation proportion. Results: Our findings revealed that out of the total 15 bacterial traits, significant associations with UTI risk were observed across both datasets. Particularly, taxon g_Ruminococcaceae UCG010 displayed a causal link with a diminished UTI risk in both datasets (ukb-b-8814: odds ratio [OR] = 0.9964, 95% confidence interval [CI] = 0.9930-0.9997, P = 0.036; GCST90013890: OR = 0.8252, 95% CI = 0.7217-0.9436, P = 0.005). However, no substantial changes in g_Ruminococcaceae UCG010 due to UTI were noted (ukb-b-8814: ß = 0.51, P = 0.87; ebi-a-GCST90013890: ß = -0.02, P = 0.77). Additionally, variations in 56 specific metabolites were induced by g_Ruminococcaceae UCG010, with N-acetylkynurenine (NAK) exhibiting a causal correlation with UTI. A negative association was found between g_Ruminococcaceae UCG010 and NAK (OR: 0.8128, 95% CI: 0.6647-0.9941, P = 0.044), while NAK was positively associated with UTI risk (OR: 1.0009; 95% CI: 1.0002-1.0016; P = 0.0173). Mediation analysis revealed that the association between g_Ruminococcaceae UCG010 and UTI was mediated by NAK with a mediation proportion of 5.07%. Discussion: This MR study provides compelling evidence supporting the existence of causal relationships between specific GM taxa and UTI, along with potential mediating metabolites.

Fucoidan Alleviates Renal Fibrosis in Diabetic Kidney Disease via Inhibition of NLRP3 Inflammasome-Mediated Podocyte Pyroptosis.

Background: Fucoidan (FPS) has been widely used to treat renal fibrosis (RF) in patients with diabetic kidney disease (DKD); however, the precise therapeutic mechanisms remain unclear. Recently, research focusing on inflammation-derived podocyte pyroptosis in DKD has attracted increasing attention. This phenomenon is mediated by the activation of the nucleotide-binding oligomerization domain (Nod)-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, leading to RF during DKD progression. Therefore, we designed a series of experiments to investigate the ameliorative effects of FPS on RF in DKD and the mechanisms that are responsible for its effect on NLRP3 inflammasome-mediated podocyte pyroptosis in the diabetic kidney. Methods: The modified DKD rat models were subjected to uninephrectomy, intraperitoneal injection of streptozotocin, and a high-fat diet. Following induction of renal injury, the animals received either FPS, rapamycin (RAP), or a vehicle for 4 weeks. For in vitro research, we exposed murine podocytes to high glucose and MCC950, an NLRP3 inflammasome inhibitor, with or without FPS or RAP. Changes in the parameters related to RF and inflammatory podocyte injury were analyzed in vivo. Changes in podocyte pyroptosis, NLRP3 inflammasome activation, and activation of the adenosine monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin complex 1 (mTORC1)/NLRP3 signaling axis involved in these changes were analyzed in vivo and in vitro. Results: FPS and RAP ameliorated RF and inflammatory podocyte injury in the DKD model rats. Moreover, FPS and RAP attenuated podocyte pyroptosis, inhibited NLRP3 inflammasome activation, and regulated the AMPK/mTORC1/NLRP3 signaling axis in vivo and in vitro. Notably, our data showed that the regulative effects of FPS, both in vivo and in vitro, on the key signaling molecules, such as p-AMPK and p-raptor, in the AMPK/mTORC1/NLRP3 signaling axis were superior to those of RAP, but similar to those of metformin, an AMPK agonist, in vitro. Conclusion: We confirmed that FPS, similar to RAP, can alleviate RF in DKD by inhibiting NLRP3 inflammasome-mediated podocyte pyroptosis via regulation of the AMPK/mTORC1/NLRP3 signaling axis in the diabetic kidney. Our findings provide an in-depth understanding of the pathogenesis of RF, which will aid in identifying precise targets that can be used for DKD treatment.

[Effects and mechanisms of Supplemented Gegen Qinlian Decoction Formula against podocyte pyroptosis and insulin resistance in model rats with diabetic kidney disease].

This study explored the in vivo effects and mechanisms of the modern classical prescription Supplemented Gegen Qinlian Decoction Formula(SGDF) against diabetic kidney disease(DKD). Sixty rats were randomly divided into the normal group, model group, SGDF group, and rosiglitazone(ROS) group. The modified DKD rat model was established by employing the following three methods: exposure to high-fat diet, unilateral nephrectomy, and intraperitoneal injection of streptozotocin(STZ). After modeling, rats in the four groups were treated with double distilled water, SGDF suspension, and ROS suspension, respectively, by gavage every day. At the end of the 6 th week of drug administration, all the rats were sacrificed for collecting urine, blood, and kidney tissue, followed by the examination of rat general conditions, urine and blood biochemical indicators, glomerulosclerosis-related indicators, podocyte pyroptosis markers, insulin resistance(IR)-related indicators, and key molecules in the insulin receptor substrate(IRS) 1/phosphatidylinositol-3-kinase(PI3 K)/serine threonine kinase(Akt) signaling pathway. The results showed that SGDF and ROS improved the general conditions, some renal function indicators and glomerulosclerosis of DKD model rats without affecting the blood glucose(BG). Besides, they ameliorated the expression characteristics and levels of podocyte pyroptosis markers, alleviated IR, and up-regulated the protein expression levels of the key molecules in IRS1/PI3 K/Akt pathway to varying degrees. In conclusion, similar to ROS, SGDF relieves DKD by targeting multiple targets in vivo. Specifically, it exerts the therapeutic effects by alleviating podocyte pyroptosis and IR. This study has preliminarily provided the pharmacological evidence for the research and development of new drugs for the treatment of DKD based on SGDF.

Total Flavones of Abelmoschus manihot Ameliorates Podocyte Pyroptosis and Injury in High Glucose Conditions by Targeting METTL3-Dependent m6A Modification-Mediated NLRP3-Inflammasome Activation and PTEN/PI3K/Akt Signaling.

Background: The total flavones of Abelmoschus manihot (TFA), a compound that is extracted from Abelmoschus manihot, has been widely used in China to reduce podocyte injury in diabetic kidney disease (DKD). However, the mechanisms underlying the therapeutic action of this compound have yet to be elucidated. Podocyte pyroptosis is characterized by activation of the NLRP3 inflammasome and plays an important role in inflammation-mediated diabetic kidneys. Regulation of the PTEN/PI3K/Akt pathway is an effective strategy for improving podocyte damage in DKD. Previous research has also shown that N6-methyladenosine (m6A) modification is involved in DKD and that m6A-modified PTEN regulates the PI3K/Akt pathway. In this study, we investigated whether TFA alleviates podocyte pyroptosis and injury by targeting m6A modification-mediated NLRP3-inflammasome activation and PTEN/PI3K/Akt signaling. Methods: We used MPC-5 cells under high glucose (HG) conditions to investigate the key molecules that are involved in podocyte pyroptosis and injury, including activation of the NLRP3 inflammasome and the PTEN/PI3K/Akt pathway. We detected alterations in the levels of three methyltransferases that are involved in m6A modification. We also investigated changes in the levels of these key molecules in podocytes with the overexpression or knockdown of methyltransferase-like (METTL)3. Results: Analysis showed that TFA and MCC950 protected podocytes against HG-induced pyroptosis and injury by reducing the protein expression levels of gasdermin D, interleukin-1ß, and interleukin-18, and by increasing the protein expression levels of nephrin, ZO-1, WT1 and podocalyxin. TFA and 740Y-P inhibited activation of the NLRP3 inflammasome via the PI3K/Akt pathway by inhibiting the protein levels of NIMA-related kinase7, NLRP3, ASC, and caspase-1, and by increasing the protein expression levels of p-PI3K and p-Akt. TFA improved pyroptosis and injury in HG-stimulated podocytes by regulating METTL3-dependent m6A modification. Conclusion: Collectively, our data indicated that TFA could ameliorate pyroptosis and injury in podocytes under HG conditions by adjusting METTL3-dependent m6A modification and regulating NLRP3-inflammasome activation and PTEN/PI3K/Akt signaling. This study provides a better understanding of how TFA can protect podocytes in DKD.

Inhibition of Renal Tubular Epithelial Mesenchymal Transition and Endoplasmic Reticulum Stress-Induced Apoptosis with Shenkang Injection Attenuates Diabetic Tubulopathy.

Background: The proximal renal tubule plays a critical role in diabetic kidney disease (DKD) progression. Early glomerular disease in DKD triggers a cascade of injuries resulting in renal tubulointerstitial disease. These pathophysiological responses are collectively described as diabetic tubulopathy (DT). Thus, therapeutic strategies targeting DT hold significant promise for early DKD treatment. Shenkang injection (SKI) has been widely used to treat renal tubulointerstitial fibrosis in patients with chronic kidney disease in China. However, it is still unknown whether SKI can alleviate DT. We designed a series of experiments to investigate the beneficial effects of SKI in DT and the mechanisms that are responsible for its effect on epithelial-to-mesenchymal transition (EMT) and endoplasmic reticulum (ER) stress-induced apoptosis in DT. Methods: The modified DKD rat models were induced by uni-nephrectomy, streptozotocin intraperitoneal injection, and a high-fat diet. Following the induction of renal injury, these animals received either SKI, rosiglitazone (ROS), or vehicle, for 42 days. For in vitro research, we exposed NRK-52E cells to high glucose (HG) and 4-phenylbutyric acid (4-PBA) with or without SKI or ROS. Changes in parameters related to renal tubular injury and EMT were analyzed in vivo. Changes in the proportion of apoptotic renal tubular cells and ER stress, and the signaling pathways involved in these changes, were analyzed both in vivo and in vitro. Results: SKI and ROS improved the general condition, the renal morphological appearance and the key biochemical parameters, and attenuated renal injury and EMT in the rat model of DKD. In addition, SKI and ROS alleviated apoptosis, inhibited ER stress, and suppressed PERK-eIF2α-ATF4-CHOP signaling pathway activation both in vivo and in vitro. Notably, our data showed that the regulatory in vitro effects of SKI on PERK-eIF2α-ATF4-CHOP signaling were similar to those of 4-PBA, a specific inhibitor of ER stress. Conclusion: This study confirmed that SKI can alleviate DT in a similar manner as ROS, and SKI achieves this effect by inhibiting EMT and ER stress-induced apoptosis. Our findings thereby provide novel information relating to the clinical value of SKI in the treatment of DT.

Total Flavones of Abelmoschus manihot Remodels Gut Microbiota and Inhibits Microinflammation in Chronic Renal Failure Progression by Targeting Autophagy-Mediated Macrophage Polarization.

BACKGROUND: Recently, progression of chronic renal failure (CRF) has been closely associated with gut microbiota dysbiosis and intestinal metabolite-derived microinflammation. In China, total flavones of Abelmoschus manihot (TFA), a component of Abelmoschus manihot, has been widely used to delay CRF progression in clinics for the past two decades. However, the overall therapeutic mechanisms remain obscure. In this study, we designed experiments to investigate the renoprotective effects of TFA in CRF progression and its underlying mechanisms involved in gut microbiota and microinflammation, compared with febuxostat (FEB), a potent non-purine selective inhibitor of xanthine oxidase. METHODS: In vivo, the CRF rat models were induced by uninephrectomy, potassium oxonate, and proinflammatory diet, and received either TFA suspension, FEB, or vehicle after modeling for 28 days. In vitro, the RAW 264.7 cells were exposed to lipopolysaccharide (LPS) with or without TFA or FEB. Changes in parameters related to renal injury, gut microbiota dysbiosis, gut-derived metabolites, and microinflammation were analyzed in vivo. Changes in macrophage polarization and autophagy and its related signaling were analyzed both in vivo and in vitro. RESULTS: For the modified CRF model rats, the administration of TFA and FEB improved renal injury, including renal dysfunction and renal tubulointerstitial lesions; remodeled gut microbiota dysbiosis, including decreased Bacteroidales and Lactobacillales and increased Erysipelotrichales; regulated gut-derived metabolites, including d-amino acid oxidase, serine racemase, d-serine, and l-serine; inhibited microinflammation, including interleukin 1ß (IL1ß), tumor necrosis factor-α, and nuclear factor-κB; and modulated macrophage polarization, including markers of M1/M2 macrophages. More importantly, TFA and FEB reversed the expression of beclin1 (BECN1) and phosphorylation of p62 protein and light chain 3 (LC3) conversion in the kidneys by activating the adenosine monophosphate-activated protein kinase-sirtuin 1 (AMPK-SIRT1) signaling. Further, TFA and FEB have similar effects on macrophage polarization and autophagy and its related signaling in vitro. CONCLUSION: In this study, we demonstrated that TFA, similar to FEB, exerts its renoprotective effects partially by therapeutically remodeling gut microbiota dysbiosis and inhibiting intestinal metabolite-derived microinflammation. This is achieved by adjusting autophagy-mediated macrophage polarization through AMPK-SIRT1 signaling. These findings provide more accurate information on the role of TFA in delaying CRF progression.

[Molecular regulative mechanisms of NLRP3 inflammasome activation in diabetic nephropathy and interventional effects of Chinese herbal medicine].

The progression of renal damage in diabetic nephropathy(DN)is closely related to Nod-like receptor protein3(NLRP3)inflammasome activation. The characteristics of NLRP3 inflammasome activation include the changed expression and combination levels of NLRP3, apoptosis-associated speck-like protein(ASC)and pro-caspase-1, the increased expression levels of caspase-1, interleukin(IL)-1ß and IL-18 and the excessive release levels of the relative inflammatory mediators. Its molecular regulative mechanisms involve the activation of multiple signaling pathways including reactive oxygen species(ROS)/thioredoxin-interacting protein(TXNIP)pathway, nuclear factor(NF)-κB pathway, nuclear factor erythroid-related factor 2(Nrf2)pathway, long non-coding RNA(lncRNA)pathway and mitogen-activated protein kinases(MAPKs)pathway. In addition, more importantly, never in mitosis aspergillus-related kinase 7(Nek7), as a kinase regulator, could target-combine with NLRP3 at upstream to activate NLRP3 inflammasome. Some extracts of Chinese herbal medicines(CHMs)such as quercetin, curcumin, cepharanthine, piperine and salidroside, as well as Chinese herbal compound prescriptions such as Wumei Pills both could treat NLRP3 inflammasome to ameliorate inflammatory renal damage in DN. Therefore, accurately clarifying the targets of anti-inflammatory CHMs and Chinese herbal compound prescriptions delaying DN progression by targeting the molecular regulative mechanisms of NLRP3 inflammasome activation will be one of the development directions in the future.

Fucoidan Ameliorates Renal Injury-Related Calcium-Phosphorus Metabolic Disorder and Bone Abnormality in the CKD-MBD Model Rats by Targeting FGF23-Klotho Signaling Axis.

Background: Recently, chronic kidney disease (CKD)-mineral and bone disorder (MBD) has become one of common complications occurring in CKD patients. Therefore, development of a new treatment for CKD-MBD is very important in the clinic. In China, Fucoidan (FPS), a natural compound of Laminaria japonica has been frequently used to improve renal dysfunction in CKD. However, it remains elusive whether FPS can ameliorate CKD-MBD. FGF23-Klotho signaling axis is reported to be useful for regulating mineral and bone metabolic disorder in CKD-MBD. This study thereby aimed to clarify therapeutic effects of FPS in the CKD-MBD model rats and its underlying mechanisms in vivo and in vitro, compared to Calcitriol (CTR). Methods: All male rats were divided into four groups: Sham, CKD-MBD, FPS and CTR. The CKD-MBD rat models were induced by adenine administration and uninephrectomy, and received either FPS or CTR or vehicle after induction of renal injury for 21 days. The changes in parameters related to renal dysfunction and renal tubulointerstitial damage, calcium-phosphorus metabolic disorder and bone lesion were analyzed, respectively. Furthermore, at sacrifice, the kidneys and bone were isolated for histomorphometry, immunohistochemistry and Western blot. In vitro, the murine NRK-52E cells were used to investigate regulative actions of FPS or CTR on FGF23-Klotho signaling axis, ERK1/2-SGK1-NHERF-1-NaPi-2a pathway and Klotho deficiency. Results: Using the modified CKD-MBD rat model and the cultured NRK-52E cells, we indicated that FPS and CTR alleviated renal dysfunction and renal tubulointerstitial damage, improved calcium-phosphorus metabolic disorder and bone lesion, and regulated FGF23-Klotho signaling axis and ERK1/2-SGK1-NHERF-1-NaPi-2a pathway in the kidney. In addition, using the shRNA-Klotho plasmid-transfected cells, we also detected, FPS accurately activated ERK1/2-SGK1-NHERF-1-NaPi-2a pathway through Klotho loss reversal. Conclusion: In this study, we emphatically demonstrated that FPS, a natural anti-renal dysfunction drug, similar to CTR, improves renal injury-related calcium-phosphorus metabolic disorder and bone abnormality in the CKD-MBD model rats. More importantly, we firstly found that beneficial effects in vivo and in vitro of FPS on phosphorus reabsorption are closely associated with regulation of FGF23-Klotho signaling axis and ERK1/2-SGK1-NHERF-1-NaPi-2a pathway in the kidney. This study provided pharmacological evidences that FPS directly contributes to the treatment of CKD-MBD.

[Multi-targeted therapeutic effects of Huangkui Capsules on insulin resistance and urine microalbumin in early diabetic kidney disease patients].

To observe the multi-targeted therapeutic effects of Huangkui Capsules(HKC)on insulin resistance(IR)and urine microalbumin in the early diabetic kidney disease(DKD)patients. The case data from the 83 DKD patients at G2 and A2 stage were collected respectively and analyzed retrospectively. According to the different treatment,all patients were divided into the control(A)group(40 cases)and the treated(B)group(43 cases). Among them,the A group patients were received "routine basic treatment";the B group patients were received "routine basic treatment+HKC". For the 2 group patients,firstly,the baseline parameters before receiving the treatment were compared respectively,and then,the changes of the total scores of traditional Chinese medicine(TCM) syndromes and the indicators of IR,urine protein,renal function,blood lipids and safety after receiving the treatment for 8 weeks were compared,respectively. Furthermore,for the all patients,the correlation analysis between IR and urine protein or IR and the total scores of TCM syndromes was carried out,respectively. The results showed that,for the B group patients received "routine basic treatment",their total scores of TCM syndromes,urine protein indicators including urine microalbumin(micro-UAlb) and urine microalbumin/urinary creatinine(UACR),IR indicators including fasting serum insulin(FIN)and homeostasis model assessment of insulin resistance(HOMA-IR)were significantly improved,respectively. For the all DKD patients,before and after the treatment,the main IR indicators(FIN and HOMA-IR)were positively correlated with urine protein indicators(micro-UAlb and UACR). The main IR indicators(FIN and HOMA-IR) were also positively correlated with the total scores of TCM syndromes. In addition,2 treatments had no significant effects on renal function,blood lipids and safety indicators in the all DKD patients. Overall, "routine basic treatment+HKC" can ameliorate IR and reduce urine microalbumin in the early DKD patients. Its therapeutic targets may be not only proteinuria,but also IR,which is the upstream risk factor of proteinuria.

[Exploring molecular mechanisms of fucoidan in improving human proximal renal tubular epithelial cells aging by targeting autophagy signaling pathways].

Fucoidan(FPS) is an effective component of the Chinese patent medicine named Haikun Shenxi, which treats schronic renal failure in clinics, and has the potential anti-aging effects. However, it is still unclear whether FPS can improve renal aging, especially the molecular mechanism of its anti-aging. The human proximal renal tubular epithelial cells(HK-2) in vitro were divided into normal group(N), D-gal model group(D), low dose of FPS group(L-FPS), high dose of FPS group(H-FPS) and vitamin E group(VE), and treated by the different measures, respectively. More specifically, the HK-2 cells in each group were separately treated by 1 mL of 1% fetal bovine serum(FBS) or D-galactose(D-gal, 75 mmol·L~(-1)) or D-gal(75 mmol·L~(-1))+FPS(25 µg·mL~(-1)) or D-gal(75 mmol·L~(-1))+FPS(50 µg·mL~(-1)) or D-gal(75 mmol·L~(-1))+VE(50 µg·mL~(-1)). After the treatment for 24 h, firstly, the effects of D-gal on senescence-associated ß-galactosidase(SA-ß-gal) staining characteristics and klotho, P53 and P21 protein expression le-vels, as well as adenosine monophosphate activated protein kinase(AMPK)-uncoordinated 51-like kinase 1(ULK1) signaling pathway activation in the HK-2 cells were detected, respectively. Secondly, the effects of FPS and VE on SA-ß-gal staining characteristics and klotho, P53 and P21 protein expression levels in the HK-2 cells exposed to D-gal were investigated, respectively. Finally, the effects of FPS and VE on microtubule-associated protein 1 light chain 3(LC3) protein expression level and AMPK-ULK1 signaling pathway activation in the HK-2 cells exposed to D-gal were examined severally. The results indicated that, for the HK-2 cells, the dose of 75 mmol·L~(-1) D-gal could induce the changes of SA-ß-gal staining characteristics and klotho, P53 and P21 protein expression levels. That is causing cells aging. FPS and VE could both ameliorate the changes of SA-ß-gal staining characteristics and klotho, P53 and P21 protein expression levels in the HK-2 cells exposed to D-gal. That is anti-cells aging, here, the functions of FPS and VE are similar. D-gal could not only induce cell aging but also increase LC3Ⅱ, phosphorylated-AMPK(p-AMPK) and phosphorylated-ULK1(p-ULK1) protein expressions, and activate autophagy-related AMPK-ULK1 signaling pathway. FPS and VE could both improve the changes of LC3Ⅱ, p-AMPK and p-ULK1 protein expression levels in the HK-2 cells exposed to D-gal. That is inhibiting autophagy-related AMPK-ULK1 signaling pathway activation. On the whole, for the human proximal renal tubular epithelial cells aging models induced by D-gal, FPS similar to VE, can ameliorate renal cells aging by possibly inhibiting autophagy-related AMPK-ULK1 signaling pathway activation. This finding provides the preliminary pharmacologic evidences for FPS protecting against renal aging.

[Molecular mechanisms of non-coding RNA regulating autophagy and interventional effects of Chinese herbal medicine].

Long non-coding RNAs(lncRNAs) and microRNAs(miRNAs),as members of the non-coding RNA family,play important roles in upstream processes that regulate autophagy in mammalian cells. LncRNA and miRNA participate in various phases of the process of autophagy,including initiation,vesicle nucleation,autophagosome maturation and autophagosome fusion. Some non-coding RNAs exert bidirectional regulatory functions in the process of autophagy,include the maternally expressed gene 3(MEG3),H19 and miR-21,whereas others either inhibit autophagy(including GAS5,miR-34 a and miR-30 a) or promote autophagy(including MALAT1,miR-152 and miR-24). The regulation of autophagy by non-coding RNAs has characteristics of conditionality,diversity and complexity. In recent years,researchers at home and abroad have constantly found that some extracts from the individual Chinese herbal medicine(CHM) such as ampelopsin,salvianolic acid B and paeonol,as well as the Chinese herbal compound named Eight Ingredients Decoction,can regulate autophagy by interacting with non-coding RNA in vitro and in vivo. The latest studies have shown that plant-derived small non-coding RNAs(sncRNAs) as one of the active ingredients of CHMs can directly enter the bloodstream and internal organs to regulate gene expressions in humans. In addition,it has been reported that rhein,hyperoside and mycelium of Cordyceps sinensis all can modulate autophagy in renal tubular epithelial cell via regulating the autophagy-related signaling pathways in vivo and in vitro to reduce renal damage and aging,which is likely mediated by the miR-34 a pathway. In summary,the understanding of molecular mechanisms underlying the regulation of autophagy by non-coding RNAs(such as lncRNAs and miRNAs) is essential and required to develop new strategies for the treatments and managements of tumors,immune diseases,metabolic diseases,neurodegenerative diseases and other common diseases and decipher pharmacologic actions of CHMs.

Total Extracts of Abelmoschus manihot L. Attenuates Adriamycin-Induced Renal Tubule Injury via Suppression of ROS-ERK1/2-Mediated NLRP3 Inflammasome Activation.

Abelmoschus manihot (L.) Medik. (Malvaceae) is a herb used in traditional Chinese medicine to treat some kidney diseases. To date, the detailed mechanisms by which A. manihot improves some kinds of renal disease are not fully understood. In this study, we established Adriamycin-induced NRK-52E cells, the normal rat kidney epithelial cell line, injury, and Sprague-Dawley rats with Adriamycin-induced nephropathy to evaluate the role and mechanisms of total extracts of A. manihot flower (TEA) both in vitro and in vivo. We found that TEA ameliorated Adriamycin-induced cellular morphological changes, cell viability, and apoptosis through the suppression of protein oxidation and ERK1/2 signaling. However, this anti-oxidative stress role of TEA was independent of ROS inhibition. Adriamycin activated ERK1/2 signaling followed by activation of NLRP3 inflammasomes. TEA suppressed NLRP3 inflammasomes via inhibition of ERK1/2 signal transduction; decreased proteinuria and attenuated renal tubule lesions; and inhibited the expression of NLRP3 in tubules in rats with Adriamycin nephropathy. Collectively, TEA protects renal tubular cells against Adriamycin-induced tubule injury via inhibition of ROS-ERK1/2-NLRP3 inflammasomes.

Shenkang injection, a modern preparation of Chinese patent medicine, diminishes tubulointerstitial fibrosis in obstructive nephropathy via targeting pericyte-myofibroblast transition.

Shenkang injection (SKI), a modern preparation of Chinese patent medicine, has been widely applied to clinical therapy in the chronic renal failure patients. However, it remains elusive whether SKI can ameliorate tubulointerstitial fibrosis (TIF) in vivo. Recently, pericyte-myofibroblast transition (PMT) plays an important role in the pathogenesis of TIF in obstructive nephropathy (ON). This report thus aims to demonstrate the therapeutic mechanisms of the dose-effects of SKI on TIF by targeting PMT and its signaling activation, compared with imatinib. All rats were divided into 5 groups, the sham-operated group, the vehicle-intervened group, the high dose of SKI-treated group, the low dose of SKI-treated group and the imatinib-treated group. The ON model rats were induced by unilateral ureteral obstruction (UUO), and administered with either the different doses of SKI or imatinib before and after modeling and for a period of 4 weeks. The changes before and after drugs intervention in TIF and PMT markers, and in platelet-derived growth factor receptor (PDGFR) and vascular endothelial growth factor receptor (VEGFR) signaling pathways activation in the kidneys were analyzed, respectively. As a result, PMT trigger was persistently accompanied with TIF exasperation in the obstructed kidneys after UUO, and that SKI definitely targeted PMT and significantly diminished TIF in vivo. In addition, the high dose of SKI, superior to imatinib, specifically blocked PMT through inhibiting the activation of PDGFR and VEGFR signaling in the kidneys of the UUO model rats. Overall, these findings may further suggest that targeting PMT can provide new strategies for ON treatment.

[Molecular mechanisms of mycelium of Cordyceps sinensis ameliorating renal tubular epithelial cells aging induced by D-galactose via inhibiting autophagy-related AMPK/ULK1 signaling activation].

To explore the effects and molecular mechanisms of mycelium of Cordyceps sinensis(MCs)improving renal tubular epithelial cells aging induced by D-galactose,the renal proximal tubular epithelial cells(NRK-52E cells)of rats in vitro were divided into the normal group(N),the D-gal model group(D),the low dose of MCs group(L-MCs),the medium dose of MCs group(M-MCs)and the high dose of MCs group(H-MCs),and treated by the different measures,respectively.More specifically,the NRK-52E cells in each group were separately treated by 1%fetal bovine serum(FBS)or D-galactose(D-gal,100 mmol·L~(-1))or D-gal(100 mmol·L~(-1))+MCs(20 mg·L~(-1))or D-gal(100 mmol·L~(-1))+MCs(40 mg·L~(-1))or D-gal(100 mmol·L~(-1))+MCs(80 mg·L~(-1)).After the intervention for24 h or 48 h,firstly,the effects of D-gal on the protein expression levels of klotho,P27 and P16,the staining of senescence-associatedß-galactosidase(SA-ß-gal)and the activation of adenosine monophosphate activated protein kinase(AMPK)/uncoordinated 51-like kinase 1(ULK1)signaling in the NRK-52E cells were detected,respectively.Secondly,the effects of MCs on the activation of the NRK-52E cells proliferation were investigated,respectively.Finally,the effects of MCs on the protein expression levels of klotho,P27,P16and microtubule-associated protein 1 light chain 3(LC3),the staining of SA-ß-gal and the activation of AMPK/ULK1 signaling in the NRK-52E cells exposed to D-gal were examined severally.The results indicated that,for the NRK-52E cells,D-gal could cause aging,induce the protein over-expression levels of the phosphorylated AMPK(p-AMPK)and the phosphorylated ULK1(p-ULK1)and activate AMPK/ULK1 signaling pathway.The co-treatment of MCs at the medium and high doses and D-gal could significantly ameliorate the protein expression levels of klotho,P27,P16 and the staining of SA-ß-gal,suggesting the anti-cell aging actions.In addition,the cotreatment of MCs at the medium and high doses and D-gal could obviously improve the protein expression levels of LC3,p-AMPK,and p-ULK1,inhibit the activation of AMPK/ULK1 signaling and increase autophagy.On the whole,for the renal tubular epithelial cells aging models induced by D-gal,MCs not only has the in vitro actions of anti-aging,but also intervenes aging process by inhibiting autophagy-related AMPK/ULK1 signaling activation,which may be the novel molecular mechanisms of MCs protecting against aging of the renal tubular epithelial cells.

[Triptolide inhibits NLRP3 inflammasome activation and ameliorates podocyte epithelial-mesenchymal transition induced by high glucose].

The aim of this paper was to explore the effects of triptolide( TP),the effective component of Tripterygium wilfordii on improving podocyte epithelial-mesenchymal transition( EMT) induced by high glucose( HG),based on the regulative mechanisms of Nod-like receptor protein 3( NLRP 3) inflammasome in the kidney of diabetic kidney disease( DKD). The immortalized podocytes of mice in vitro were divided into the normal( N) group,the HG( HG) group,the low dose of TP( L-TP) group,the high dose of TP( HTP) group and the mannitol( MNT) group,and treated by the different measures,respectively. More specifically,the podocytes in each group were separately treated by D-glucose( DG,5 mmol·L~(-1)) or HG( 30 mmol·L~(-1)) or HG( 30 mmol·L~(-1)) + TP( 5 µg·L~(-1))or HG( 30 mmol·L~(-1)) + TP( 10 µg·L~(-1)) or DG( 5 mmol·L~(-1)) + MNT( 24. 5 mmol·L~(-1)). After the treatment of HG or TP at 24,48 and 72 h,firstly,the activation of podocyte proliferation was investigated. Secondly,the protein expression levels of the epithelial markers in podocytes such as nephrin and ZO-1,the mesenchymal markers such as collagen Ⅰ and fibronectin( FN) were detected,respectively. Finally,the protein expression levels of NLRP3 and apoptosis-associated speck-like protein( ASC) as the key signaling molecules of NLRP3 inflammasome activation,as well as the downstream effector proteins including caspase-1,interleutin( IL)-1ß and IL-18 were examined,severally. The results indicated that,for the cultured podocytes in vitro,HG could cause the low protein expression levels of nephrin and ZO-1,induce the high protein expression levels of collagen Ⅰ and FN and trigger podocyte EMT. Also HG could cause the high protein expression levels of NLRP3,ASC,caspase-1,IL-1ß and IL-18 and induce NLRP3 inflammasome activation. On the other hand,the co-treatment of TP( L-TP or H-TP) and HG for podocytes could recover the protein expression levels of nephrin and ZO-1,inhibit the protein expression levels of collagen Ⅰ and FN and ameliorate podocyte EMT. Also the co-treatment of TP( L-TP or H-TP) and HG could down-regulate the protein expression levels of NLRP3 and ASC,inhibit NLRP3 inflammasome activation and reduce the protein expression levels of the downstream effector molecules including caspase-1,IL-1ß and IL-18. On the whole,HG could activate NLRP3 inflammasome and induce podocyte EMT in vitro. TP at the appropriate dose range could inhibit NLRP3 inflammasome activation and ameliorate podocyte EMT,which may be one of the critical molecular mechanisms of TP protecting againstpodocyte inflammatory injury in DKD.

[Pathomechanisms of pericyte-myofibroblast transition in kidney and interventional effects of Chinese herbal medicine].

In the kidney, pericyte is the major source of myofibroblast (MyoF) in renal interstitium. It is reported that pericyte-myofibroblast transition（PMT）is one of the important pathomechanisms of renal interstitial fibrosis（RIF）. Among them, the main reasons for promoting RIF formation include pericyte recruitment, activation and isolation, as well as the lack of pericyte-derived erythropoietin. During the PMT startup process, pericyte activation and its separation from microvessels are controlled by multiple signal transduction pathways, such as transforming growth factor-ß（TGF-ß）pathway, vascular endothelial growth factor receptor (VEGFR) pathway and platelet derived growth factor receptor (PDGFR) pathway;Blocking of these signaling pathways can not only inhibit PMT, but also suppress renal capillaries reduction and further alleviate RIF. In clinic, many traditional Chinese medicine compound prescriptions, single traditional Chinese herbal medicine (CHM) and their extracts have the clear effects in alleviating RIF, and some of their intervention actions may be related to pericyte and its PMT. Therefore, the studies on PMT and its drug intervention will become the main development direction in the research field of anti-organ fibrosis by CHM.

Hyperoside attenuates renal aging and injury induced by D-galactose via inhibiting AMPK-ULK1 signaling-mediated autophagy.

The kidney is a typical organ undergoing age and injury. Hyperoside is reported to be useful for preventing aging induced by D-galactose (D-gal). However, therapeutic mechanisms remain unclear. We thereby aimed to verify whether hyperoside, compared to vitamin E (VE), could alleviate renal aging and injury by regulating autophagic activity and its related signaling pathways. In vivo, rats were administered with either hyperoside or VE after renal aging modeling induced by D-gal. Changes in renal aging and injury markers, autophagic activity and AMPK-ULK1 signaling pathway in the kidneys were analysed. In vitro, the NRK-52E cells exposed to D-gal were used to investigate regulative actions of hyperoside and VE on cell viability, renal tubular cellular aging markers, autophagic activity and its related signaling pathways by histomorphometry, immunohistochemistry, immunofluorescence, lentiviral transfection and Western blot. Aging and injury in the kidneys and renal tubular cells induced by D-gal were ameliorated by hyperoside and VE. Hyperoside and VE inhibited autophagic activity through mTOR-independent and AMPK-ULK1 signaling pathways. Hyperoside, as a component of phytomedicine similar to VE, attenuated renal aging and injury induced by D-gal via inhibiting AMPK-ULK1-mediated autophagy. This study provides the first evidence that hyperoside contributes to the prevention of age-associated renal injury.

[Low dose of triptolide ameliorates podocyte epithelial-mesenchymal transition induced by high dose of D-glucose via inhibiting Wnt3α/ß-catenin signaling pathway activation].

To explore the effects and molecular mechanisms of triptolide（TP）on improving podocyte epithelial-mesenchymal transition（EMT）induced by high dose of D-glucose（HG）, the immortalized podocytes of mice in vitro were divided into the normal group（N）, the high dose of D-glucose group（HG）, the low dose of TP group（L-TP）, the high dose of TP group（H-TP）and the mannitol group（MNT）, and treated by the different measures respectively. More specifically, the podocytes in each group were separately treated by D-glucose（DG, 5 mmol·L⁻¹ï¼‰or HG（25 mmol·L⁻¹ï¼‰or HG（25 mmol·L⁻¹ï¼‰+ TP（3 µg·L⁻¹ï¼‰or HG（25 mmol·L⁻¹ï¼‰+ TP（10 µg·L⁻¹ï¼‰or DG（5 mmol·L⁻¹ï¼‰+ MNT（24.5 mmol·L⁻¹ï¼‰. After the intervention for 24, 48 and 72 hours, firstly, the activation of podocyte proliferation was investigated. Secondly, the protein expression levels of the epithelial markers in podocytes such as nephrin and podocin, the mesenchymal markers such as desmin and collagen Ⅰ and the EMT-related mediators such as snail were detected respectively. Finally, the protein expression levels of Wnt3α and ß-catenin as the key signaling molecules in Wnt3α/ß-catenin pathway were examined severally. The results indicated that, HG could cause the low protein expression levels of nephrin and podocin and the high protein expression levels of desmin, collagen Ⅰ and snail in podocytes, and inducing podocyte EMT. On the other hand, HG could cause the high protein expression levels of Wnt3α and ß-catenin in podocytes, and activating Wnt3α/ß-catenin signaling pathway. In addition, L-TP had no effect on the activation of podocyte proliferation, the co-treatment of L-TP and HG could significantly recover the protein expression levels of nephrin and podocin, inhibit the protein expression levels of desmin, collagen I and snail in podocytes, thus, further improving podocyte EMT. And that, the co-treatment of L-TP and HG could obviously decrease the high protein expression levels of Wnt3α and ß-catenin induced by HG in podocytes, and inhibit Wnt3α/ß-catenin signaling pathway activation. On the whole, HG can induce podocyte EMT by activating Wnt3α/ß-catenin signaling pathway; L-TP can ameliorate podocyte EMT through inhibiting Wnt3α/ß-catenin signaling pathway activation, which may be one of the effects and molecular mechanisms in vitro.

[Molecular regulative mechanisms of aging and interventional effects of Chinese herbal medicine].

Aging is a gradual process during the loss of functions in cells,organs and tissues by time. The molecular mechanisms of aging-related theories include the classical ones such as telomere,oxygen radical and nonenzymatic glycosylation,as well as the newly proposed ones such as DNA methylation,mitochondrial DNA （mtDNA）and autophagy. The latest study showed the anti-aging effect of autophagy in hematopoietic stem cells. In recent years,based on the molecular regulative mechanisms of aging,a number of the promising anti-aging drugs have been found,including nicotinamide mononucleotide（NMN）and FOXO4-DRI,a peptide of anti-aging. In addition,there are many new discoveries in the field of plant extracts,in which,the extracts from Chinese herbal medicine（CHM）,some single CHMs and the classical prescriptions of CHM,represented by curcumin and resveratrol,have the partial anti-aging effects by regulating the molecular mechanisms of aging both in vivo and in vitro. In brief,developing or exploring anti-aging drugs,especially the natural drugs,is one of the main development directions in the field of anti-aging research in the basis of the molecular regulative mechanisms of aging.