Inflammation Is More Sensitive than Cell Proliferation in Response to Rapamycin Treatment in Polycystic Kidney Disease.

INTRODUCTION: It has been reported that rapamycin inhibited inflammation in renal interstitial diseases. We therefore hypothesized that rapamycin could attenuate inflammation in polycystic kidney disease (PKD). METHODS: Han:SPRD rats were treated with rapamycin by daily gavage from 4 weeks to 12 weeks of age at the dosage of 0.5 mg/kg/day (low dose) or 1 mg/kg/day (high dose). WT9-12 human PKD cells were treated with various concentrations of rapamycin. RESULTS: Two-kidney/total body weight ratio and cystic index in Cy/+ kidneys were significantly reduced with the treatment of low-dose rapamycin and further reduced by the treatment with high-dose rapamycin. However, the renal function of Cy/+ rats was equally improved by the treatment with either low-dose or high-dose rapamycin. The renal cell proliferation was significantly decreased in Cy/+ kidneys with the treatment of low-dose rapamycin and was further decreased with the treatment of high-dose rapamycin as examined by Ki67 staining. The phosphorylation of S6K in cystic kidneys was decreased by low-dose rapamycin and further decreased by high-dose rapamycin. Both low-dose and high-dose rapamycin treatment decreased macrophage infiltration and the expression of complement factor B (CFB), monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor-alpha (TNF-α) to a similar level. The expression of CFB, MCP-1, and TNF-α and phosphorylation of S6K were inhibited in WT9-12 cells treated with 10 nm rapamycin at 24 h and 48 h, respectively. Moreover, the phosphorylation of Akt was not increased by 1 nm and 10 nm of rapamycin and enhanced by 1 µm rapamycin treatment. Interestingly, WT9-12 cell proliferation could be inhibited by 1 µm rapamycin. CONCLUSION: Low dose of rapamycin could inhibit inflammation and protect renal function in PKD. Inflammation is more sensitive than cell proliferation in response to rapamycin treatment in PKD.

A pilot study of intensive short-time continuous renal replacement therapy to substitute maintenance hemodialysis during transitional period of COVID-19.

INTRODUCTION: There is a lack of perfect solutions for maintenance hemodialysis (MHD) in patients with a high transmission risk of SARS-CoV-2. METHODS: MHD patients with a high risk of SARS-CoV-2 transmission from April 1 to June 30, 2022, were recruited. We performed 4-h continuous renal replacement therapy with Prismaflex dialysis machine and ST100 suite using continuous venovenous hemodiafiltration (CVVHDF) mode with a fluid exchange volume of 8000 mL/h. RESULTS: Forty-five MHD patients were included with a median dialysis age of 91 months. Overall spKt/V reached 0.96 ± 0.19. Urea reduction ratio was 50.29 ± 7.60% with the ultrafiltration of 2.18 ± 0.79 kg. Dry weight was significantly inversely correlated with spKt/V (R = -0.563, p < 0.001). Female gender was a significant positive factor of spKt/V. Preheating of replacement solution using an incubator solved the complication of shivering in most patients. CONCLUSION: Intensive short-time CVVHDF may be considered as an alternative for routine MHD during COVID-19 transitional period.

Assembly of porous filaments by interfacial complexation of nanochitin-based Pickering emulsion and seaweed alginate.

Interfacial polyelectrolyte complexation spinning is an all-water, easy-to-operate method for production of composite filaments. Herein, this concept is extended to interfacial polyelectrolyte-emulsion complexation (IPEC) that better encodes structural and functional attributes of biomass substances into the filaments. This allows for formation of composite filaments by drawing contacting oppositely-charged chitin nanofiber-stabilized Pickering emulsion and seaweed alginate solution. The parameters affecting spinnability of the system including water-to-oil ratio, alginate concentration, and pH are comprehensively elucidated to support the design and application of IPEC. The composite filaments exhibit varied diameters and diverse porous structures that are adjustable by properties of Pickering droplets. The droplet diameter of precursor emulsion and pore size in the filaments are well correlated, revealing controllability of the IPEC spinning. The filaments are mechanically robust in dry condition and show stable performance even in wet condition. The release rate of filaments that is pre-loaded with hydrophilic drug is regulated by the internal pore size, showing capability on sustained release. This study offers a new perspective toward dry spinning via interfacial complexation of complicated nanochitin-based structural building blocks, aiming at developing high-performance fiber materials for advanced applications.

Enhanced Cartilage and Subchondral Bone Repair Using Carbon Nanotube-Doped Peptide Hydrogel-Polycaprolactone Composite Scaffolds.

A carbon nanotube-doped octapeptide self-assembled hydrogel (FEK/C) and a hydrogel-based polycaprolactone PCL composite scaffold (FEK/C3-S) were developed for cartilage and subchondral bone repair. The composite scaffold demonstrated modulated microstructure, mechanical properties, and conductivity by adjusting CNT concentration. In vitro evaluations showed enhanced cell proliferation, adhesion, and migration of articular cartilage cells, osteoblasts, and bone marrow mesenchymal stem cells. The composite scaffold exhibited good biocompatibility, low haemolysis rate, and high protein absorption capacity. It also promoted osteogenesis and chondrogenesis, with increased mineralization, alkaline phosphatase (ALP) activity, and glycosaminoglycan (GAG) secretion. The composite scaffold facilitated accelerated cartilage and subchondral bone regeneration in a rabbit knee joint defect model. Histological analysis revealed improved cartilage tissue formation and increased subchondral bone density. Notably, the FEK/C3-S composite scaffold exhibited the most significant cartilage and subchondral bone formation. The FEK/C3-S composite scaffold holds great promise for cartilage and subchondral bone repair. It offers enhanced mechanical support, conductivity, and bioactivity, leading to improved tissue regeneration. These findings contribute to the advancement of regenerative strategies for challenging musculoskeletal tissue defects.

The Role of Negative Perfectionism and the Relationship between Critical Thinking and the Halo Effect: Insights from Corporate Managers in Human Resources.

This research aims to explore the relationship between critical thinking and the halo effect among managers working in the Human Resources (HR) departments of corporations. By utilizing a sample of over 301 corporate HR managers as participants, this study provides valuable insight into the dynamics between critical thinking, the halo effect, and the mediating role of negative perfectionism. The findings of this study suggest a significant negative relationship between critical thinking and the halo effect, as well as a significant positive relationship between negative perfectionism and the halo effect. Notably, negative perfectionism acts as a mediator between critical thinking and the halo effect. Our research also reveals that compensation level moderates this relationship, with lower-income HR managers exhibiting a stronger association between negative perfectionism and the halo effect compared to higher-income HR managers. These findings significantly contribute to our understanding of the interplay between critical thinking and the halo effect among HR managers in corporate settings. Identifying negative perfectionism as a mediating factor clarifies the underlying mechanisms between critical thinking and the halo effect, while the moderating effect of compensation level highlights the importance of considering contextual factors. The practical implications of this research include the significance of promoting critical thinking skills among HR managers to mitigate the halo effect in job recruitment and performance evaluation. Additionally, organizations should prioritize fairness and consistency in compensation levels to minimize the influence of negative perfectionism and its impact on the halo effect.

Histone H3K27 methyltransferase EZH2 regulates apoptotic and inflammatory responses in sepsis-induced AKI.

Rationale: The role of histone methylation modifications in renal disease, particularly in sepsis-induced acute kidney injury (AKI), remains unclear. This study aims to investigate the potential involvement of the histone methyltransferase zeste homolog 2 (EZH2) in sepsis-induced AKI and its impact on apoptosis and inflammation. Methods: We first examined the expression of EZH2 in the kidney of sepsis-induced AKI (LPS injection) mice and LPS-stimulated tubular epithelial cells. We next constructed the EZH2 knockout mice to further confirm the effects of EZH2 on apoptosis and inflammatory response in AKI. And the inflammatory level of epithelial cells can be reflected by detecting chemokines and the chemotaxis of macrophages. Subsequently, we constructed the EZH2 knocked-down cells again and performed Chromatin Immunoprecipitation sequencing to screen out the target genes regulated by EZH2 and the enrichment pathway. Then we confirmed the EZH2 target gene and its regulatory pathway in vivo and in vitro experiments. Experimental results were finally confirmed using another in vivo model of sepsis-induced AKI (cecal perforation ligation). Results: The study found that EZH2 was upregulated in sepsis-induced AKI and that silencing EZH2 could reduce renal tubular injury by decreasing apoptosis and inflammatory response of tubular epithelial cells. EZH2 knockout mice showed significantly reduced renal inflammation and macrophage infiltration. Chromatin immunoprecipitation sequencing and polymerase chain reaction identified Sox9 as a target of EZH2. EZH2 was found to be enriched on the promoter of Sox9. Silencing EZH2 resulted in a significant increase in the transcriptional level of Sox9 and activation of the Wnt/ß-catenin signaling pathway. The study further reversed the effects of EZH2 silencing by silencing Sox9 or administering the Wnt/ß-catenin inhibitor icg001. It was also found that Sox9 positively regulated the expression of ß-catenin and its downstream pathway-related genes. Finally, the study showed that the EZH2 inhibitor 3-deazaneplanocin A significantly alleviated sepsis-induced AKI. Conclusion: Our results indicate that silencing EZH2 can protect renal function by relieving transcriptional inhibition of Sox9, activating the Wnt/ß-catenin pathway, and attenuating tubular epithelial apoptosis and inflammatory response of the renal interstitium. These results highlight the potential therapeutic value of targeting EZH2 in sepsis-induced AKI.

Dehydration Accelerates Cytogenesis and Cyst Growth in Pkd1-/- Mice by Regulating Macrophage M2 Polarization.

Adult autosomal dominant polycystic kidney disease (ADPKD) has been shown to be related as a "third hit" to the occurrence of acute or chronic kidney injury. Here, we examined whether dehydration, as a common kidney risk factor, could cause cystogenesis in chronic-onset Pkd1-/- mice by regulating macrophage activation. First, we confirmed that dehydration accelerated cytogenesis in Pkd1-/- mice and that macrophages infiltrated the kidney tissues even earlier than macroscopic cyst formation. Then, microarray analysis suggested that glycolysis pathway may be involved in macrophage activation in Pkd1-/- kidneys under conditions of dehydration. Further, we confirmed glycolysis pathway was activated and lactic acid (L-LA) was overproduced in the Pkd1-/- kidney under conditions of dehydration. We have already proved that L-LA strongly stimulated M2 macrophage polarization and overproduction of polyamine in macrophage in vitro, and in the present study, we further discovered that M2 polarization-induced polyamine production shortened the primary cilia length by disrupting the PC1/PC2 complex. Finally, the activation of L-LA-arginase 1-polyamine pathway contributed to cystogenesis and progressive cyst growth in Pkd1-/- mice recurrently exposed to dehydration.

Macrophages promote heat stress nephropathy in mice via the C3a-C3aR-TNF pathway.

Heat-stress nephropathy (HSN) is associated with recurrent dehydration. However, the mechanisms underlying HSN remain largely unknown. In this study, we evaluated the role of dehydration in HSN and kidney injury in mice. Firstly, we found that complement was strongly activated in the mice that were exposed to dehydration; and among complement components, the interaction between C3a and its receptor, C3aR, was more closely associated with kidney injury. Then two-month-old mice were intraperitoneally injected with 2% dimethyl sulfoxide (DMSO) or the C3aR inhibitor SB290157 during dehydration. DMSO-treated mice exhibited excessive macrophage infiltration, renal cell apoptosis, and kidney fibrosis. In contrast, SB290157-treated mice had no apparent kidney injury. By fluorescence-activated cell sorting (FACS), we found that SB290157 treatment in mice remarkably inhibited macrophage infiltration and suppressed CCR2 expression in macrophages. In addition, C3a binding to C3aR promoted macrophage polarization toward the M1 phenotype and increased the production of TNF-α, which induced renal tubular epithelial cell (RTEC) apoptosis in vivo and in vitro. Interestingly, C3a treatment failed to directly induce TNF-α production and apoptosis in RTECs. However, TNF-α production in response to C3a treatment was significantly elevated when RTECs were cocultured with macrophages, suggesting that macrophages rather than RTECs are the target of C3a-C3aR interaction. At last, we proved that infusion of macrophages which highly expressed TNF-α would significantly deteriorate HSN in TNF-KO mice when they were exposed to recurrent dehydration. This study uncovers a novel mechanism underlying the pathogenesis of HSN, and a potential pathway to prevent kidney injury during dehydration.

Cell-free and cytokine-free self-assembling peptide hydrogel-polycaprolactone composite scaffolds for segmental bone defects.

Segmental bone defects over the self-healing threshold are a major challenge for orthopedics. Despite the advancements in clinical practice, traditional tissue engineering methods are limited by the addition of heterogeneous cells and cytokines, leading to carcinoma or other adverse effects. Here, we present a cell-free and cytokine-free strategy using an ECM-mimetic self-assembling peptide hydrogel (SAPH)- polycaprolactone (PCL) composite scaffold. The hydrophilic SAPH endows the rigid PCL scaffold with excellent biocompatibility and preference for osteogenesis induction. The autologous cells around the bone defect site immediately grew, proliferated, and secreted ECM and cytokines after contacting the implanted SAPH-PCL composite scaffold, and the bone repair of rabbit ulnar segmental bone defect was achieved in just six months. Quantitative proteomic analysis reveals that the SAPH-PCL composite scaffold accelerates osteoblastogenesis, osteoclastogenesis, and angiogenesis with moderate immune responses and negligible effects on pathological fibrosis. These findings have important implications for the potential clinical applications of the SAPH-PCL composite scaffold in patients with segmental bone defects and identify the mechanisms of action for accelerated segmental bone defect repair.

Deaf and hearing children: A comparison of face perception.

Deaf and hearing adults perceive faces differently. This study investigates whether these differences are acquired during childhood development. We characterized facial perception in deaf and hearing children aged 7-17 using a perceptual discrimination task. Configural and featural information was manipulated in the eye and mouth facial regions. Participants were asked whether two faces presented simultaneously were different. Deaf and hearing children performed better in featural than configural discriminations and in mouth than eye discriminations. Compared with children with typical hearing, deaf children performed better in featural and mouth judgments but had longer reaction times with strongest effects at 7-8 and 13-14 years old. Type and location contributed jointly in deaf children's face perception with different configural but similar featural discriminations in mouth and eye locations. However, children with typical hearing showed different featural and configural judgments in both locations. Thus, featural and configural information effects on location processing differ between the two groups.

In-center Nocturnal Hemodialysis Reduced the Circulating FGF23, Left Ventricular Hypertrophy, and All-Cause Mortality: A Retrospective Cohort Study.

Fibroblast growth factor 23(FGF23) is the most important biomarker and pathogenic factor in Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD). In the moderate and severe stages of chronic renal failure, abnormally elevated circulating FGF23 can lead to some complications, including myocardial hypertrophy, which is positively correlated with all-cause mortality. However, the circulating FGF23 level of different hemodialysis modalities, the underlying essential regulatory factors, and potential clinical benefits remain to be elucidated. In this retrospective cohort study, 90 in-center nocturnal hemodialysis (INHD) and 90 matched conventional hemodialysis (CHD) patients were enrolled. The complete blood count, intact FGF23(iFGF23), calcium, phosphorus, PTH, and other biochemical and echocardiographic parameters of INHD and CHD patients were collected and analyzed at 1-year follow-up. The all-cause mortality was recorded during the 7-year follow-up. Furthermore, the regulatory factors of iFGF23 and its association with echocardiographic parameters and mortality were investigated by multivariate regression. The levels of iFGF23 and serum phosphate in patients undergoing INHD were significantly lower than those in patients undergoing CHD. The left ventricular volume index (LVMI) in patients with INHD was significantly attenuated and positively correlated with the drop of serum iFGF23. The INHD group had reduced all-cause mortality compared to the CHD group. Multivariate analysis showed that iFGF23 was positively correlated with serum calcium, serum phosphorus, and calcium-phosphate product. The calcium-phosphate product is an independent determining factor of serum iFGF23. Compared with the CHD group, the INHD group presented with a significantly reduced circulating iFGF23 level, which was closely associated with attenuation of left ventricular hypertrophy, but INHD reduced all-cause mortality in an FGF23 independent manner.

Peptide-drug conjugate-based novel molecular drug delivery system in cancer.

Drug delivery systems are generally believed to comprise drugs and excipients. A peptide-drug conjugate is a single molecule that can simultaneously play multiple roles in a drug delivery system, such as in vivo drug distribution, targeted release, and bioactivity functions. This molecule can be regarded as an integrated drug delivery system, so it is called a molecular drug delivery system. In the context of cancer therapy, a peptide-drug conjugate comprises a tumor-targeting peptide, a payload, and a linker. Tumor-targeting peptides specifically identify membrane receptors on tumor cells, improve drug-targeted therapeutic effects, and reduce toxic and side effects. Payloads with bioactive functions connect to tumor-targeting peptides through linkers. In this review, we explored ongoing clinical work on peptide-drug conjugates targeting various receptors. We discuss the binding mechanisms of tumor-targeting peptides and related receptors, as well as the limiting factors for peptide-drug conjugate-based molecular drug delivery systems.

Naked-eye detection of site-specific ssRNA and ssDNA using PAMmer-assisted CRISPR/Cas9 coupling with exponential amplification reaction.

Accurate and effective detection of single-stranded nucleic acids is vital in both disease diagnosis and pathological studies. Hence, we develop a PAMmer-assisted CRISPR/Cas9 system mediated G4-EXPAR (Cas-G4EX) strategy for site-specific detection of ssRNA and ssDNA. PAMmer-assisted CRISPR/Cas9 executes the site-specific cleavage of target ssRNA or ssDNA and released product fragment with the desired sequence at the 3'-terminal. This fragment serves as a primer to activate subsequent sequence-dependent exponential amplification reaction (EXPAR). The G-rich EXPAR products assembles with hemin to form a G-Quadruplex (G4/hemin). G4/hemin catalyzes ABTS-H2O2 system with the appearance of vivid green color, realizing naked-eye analysis. Cas-G4EX integrates the superiority of CRISPR/Cas9 and EXPAR, presenting outstanding site-specific recognition and high-performance amplification efficiency. Meanwhile, the programmability of CRISPR/Cas9 system makes the proposed method become a universal detection paradigm for any ssRNA or ssDNA. Cas-G4EX assay shows the linear relationship from 250 aM to 2.5 nM for ssRNA detection with the actual LOD of 250 aM, and that ranges from 100 aM to 1 nM for ssDNA detection with the actual LOD of 100 aM. Additionally, the acceptable recoveries of 101.48%-109.61% for ssRNA and 93.25%-111.98% for ssDNA in real detection of human serum are obtained for detection of single-strand nucleic acid in real samples. Cas-G4EX also exhibits the excellent discrimination for single-base mutation of single-stranded nucleic acids. Therefore, Cas-G4EX assay provides a promising platform in the applications of molecular diagnosis and pathological analysis.

Simultaneous measurement of Cr(III) and Cu(II) based on indicator-displacement assay using a colorimetric nanoprobe.

High-performance analysis of heavy metal ions is great importance in both environment and food safety. In this work, a facile and reliable colorimetric sensor was presented for simultaneous detection of Cu2+ and Cr3+ based on indicator-displacement assay (IDA). As a typical silicate nanomaterials, ZnSiO3 hollow nanosphere (ZSHS) exhibited an outstanding ion exchange capacity. Zincon was incorporated with the ZSHS to form a zincon/ZSHS hybrid ionophore with a blue color. Upon the addition of Cr3+, IDA reaction and selective ion exchange occurred with the color change of zincon/ZSHS ionophore from blue to yellow. With such a design, colorimetric measurement of Cr3+ was realized. The linear concentration for Cr3+ detection ranged from 0.5 µM to 75 µM with the LOD of 83.2 nM. Furthermore, we also screened different kinds of complexing agents that may respond with zincon/ZSHS ionophore and various metal ions. It was found that tartaric acid (TA) showed the chelation capability of Zn2+-TA is stronger than that of Zn2+-zincon. Thus zincon/ZSHS/TA presented a yellow color due to the chelation reaction of Zn2+-TA, releasing the zincon as a free state. After addition of Cu2+, a stronger chelation reaction of Cu2+-zincon occurred. This process involved in the color change from yellow to blue and realized colorimetric measurement of Cu2+. The detection limit of Cu2+ was calculated to be 43.7 nM with linear range from 0.1 to 20 µM. In addition, the zincon/ZSHS nanoprobe was successfully applied for simultaneous measurement of Cu2+ and Cr3+ in sorghum and river water, indicating that the zincon/ZSHS nanoprobe provided a promising sensing platform in environment and food safety.

A turn-on fluorescent nanoprobe based on N-doped silicon quantum dots for rapid determination of glyphosate.

N-Doped silicon quantum dots (N-SiQD) were synthesized using N-[3-(trimethoxysily)propyl]-ethylenediamine and citric acid as silicon source and reduction agent, respectively. The N-SiQD shows a strong blue fluorescence with a high quantum yield of about 53%. It is found that a selective static quenching process occurs between N-SiQDs and Cu2+. Glyphosate can inhibit this phenomenon and trigger the rapid fluorescence enhancement of the quenched N-SiQDs/Cu2+ system due to the specific interaction between Cu2+ and glyphosate. With such a design, a turn-on fluorescent nanoprobe based on N-SiQD/Cu2+ system was established for rapid determination of glyphosate. The determination signal of N-SiQD/Cu2+ was measured at the optimum emission wavelength of 460 nm after excitation at 360 nm. Under optimal conditions, the turn-on nanoprobe showed a linear relationship between fluorescent response and glyphosate concentrations in the range 0.1 to 1 µg mL-1. The limit of determination was calculated to 7.8 ng mL-1 (3σ/S). Satisfactory recoveries were obtained in the determination of spiked water samples, indicating the potential use for environmental monitoring. Graphical abstract Schematic representation of N-SiQD/Cu2+ system for glyphosate determination. Fluorescence quenching of N-SiQDs induced by copper ions and the succedent fluorescent "turn on" triggered by glyphosate.

Long non-coding RNAs in ocular diseases: new and potential therapeutic targets.

Long non-coding RNAs (lncRNAs) are non-protein coding transcripts containing more than 200 nucleotides. In the past, lncRNAs were considered as 'transcript noise' or 'pseudogenes' and were thus ignored. However, in recent years, lncRNAs have been proven to regulate gene expression at the epigenetic, transcriptional and translational level, and thereby influence cell proliferation, apoptosis, viability, immune response and oxidative stress. Furthermore, increasing evidence points to their involvement in different diseases, including cancer and heart diseases. Recently, lncRNAs were shown to be differentially expressed in ocular tissues and play a significant role in the pathogenesis of ophthalmological disorders such as glaucoma, corneal diseases, cataract, diabetic retinopathy, proliferative vitreoretinopathy and ocular tumors. In this review, we summarize the classification and mechanisms of known lncRNAs, while detailing their biological functions and roles in ocular diseases. Moreover, we provide a concise review of the clinical relevance of lncRNAs as novel, potential therapeutic targets in the treatment of eye diseases.

An in situ hydrogel based on carboxymethyl chitosan and sodium alginate dialdehyde for corneal wound healing after alkali burn.

There is currently no optimal scaffold for the transplantation of limbal stem cells (LSCs) to induce corneal reconstruction after corneal alkali burns. This study attempts to fabricate a novel in situ Alginate-Chitosan hydrogel (ACH) for LSCs transplantation. Sodium alginate dialdehyde (SAD), a biological crosslinker, was prepared by periodate-mediated sodium alginate oxidization. Carboxymethyl chitosan was rapidly crosslinked with SAD via Schiff's base formation between the available aldehyde and amino groups. The ACH is rapidly formed on the wound surface by self-crosslinking without adding any chemical crosslinking component. Gelation time, transmittance, microscopic structure, equilibrium swelling, cytotoxicity, histocompatibility and degradability of the hydrogel were all examined. Rabbit primary LSCs were encapsulated in the hydrogel and transplanted to alkali burn wounds in vivo. Cornea reconstruction was evaluated by visual observation, slit lamp, histological analysis, and immunofluorescence staining. Results showed that the in situ hydrogel was highly transparent, gelated quickly, biocompatible, and had low cytotoxicity. LSCs cultured in vitro expressed the stem marker p63 but lacked the differentiated epithelial markers cytokeratin 3 and 12. Furthermore, the hydrogel encapsulating LSCs could be formed quickly on the alkali burn wound of the cornea and was shown to significantly improve epithelial reconstruction. Taken together, treatment with this novel in situ hydrogel-mediated LSC transplantation system may serve as a rapid and effective method for corneal wound healing. © 2018 The Authors. Journal of Biomedical Materials Research Part A published by Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 742-754, 2019.

Interactions between Macrophages and Cyst-Lining Epithelial Cells Promote Kidney Cyst Growth in Pkd1-Deficient Mice.

BACKGROUND: Autosomal-dominant polycystic kidney disease (ADPKD) is the leading inherited renal disease worldwide. The proproliferative function of macrophages is associated with late-stage cyst enlargement in mice with PKD; however, the way in which macrophages act on cyst-lining epithelial cells (CLECs) has not been well elucidated. METHODS: We generated a rapid-onset PKD mouse model by inactivating Pkd1 on postnatal day 10 (P10) and compared cell proliferation and differential gene expression in kidney tissues of the PKD mice and wild-type (WT) littermates. RESULTS: The cystic phenotype was dominant from P18. A distinct peak in cell proliferation in polycystic kidneys during P22-P30 was closely related to late-stage cyst growth. Comparisons of gene expression profiles in kidney tissues at P22 and P30 in PKD and WT mice revealed that arginine metabolism was significantly activated; 204 differentially expressed genes (DEGs), including Arg1, an arginine metabolism-associated gene, were identified in late-stage polycystic kidneys. The Arg1-encoded protein, arginase-1 (ARG1), was predominantly expressed in macrophages in a time-dependent manner. Multiple-stage macrophage depletion verified that macrophages expressing high ARG1 levels accounted for late-stage cyst enlargement, and inhibiting ARG1 activity significantly retarded cyst growth and effectively lowered the proliferative indices in polycystic kidneys. In vitro experiments revealed that macrophages stimulated CLEC proliferation, and that L-lactic acid, primarily generated by CLECs, significantly upregulated ARG1 expression and increased polyamine synthesis in macrophages. CONCLUSIONS: Interactions between macrophages and CLECs promote cyst growth. ARG1 is a key molecule involved in this process and is a potential therapeutic target to help delay ADPKD progression.

Lactoferrin attenuates high-fat diet-induced hepatic steatosis and lipid metabolic dysfunctions by suppressing hepatic lipogenesis and down-regulating inflammation in C57BL/6J mice.

Lactoferrin was reported to exert modulatory effects on lipid metabolism, but the regulatory mechanisms remain unclear. The present study investigated the beneficial effects of lactoferrin and their underlying mechanisms in high-fat diet-induced obese C57BL/6J mice. Oral administration of lactoferrin at 100 mg per body weight for 15 weeks significantly reduced weight gain, visceral adiposity, and serum glucose, leptin, and lipid levels in high-fat diet-induced obese mice. Hepatic steatosis in the obese mice was significantly improved. Expression of adipogenic and inflammation-related genes and proteins (SREBP-1c, FAS, MCP-1, leptin) was suppressed in the liver and epididymal adipose tissue of the obese mice. The present findings demonstrate that lactoferrin positively regulated lipid metabolism and improved hepatic steatosis in obese mice. The mechanisms of action for these effects may be attributed to suppression of lipogenic gene expression and amelioration of inflammation in the liver and epididymal adipose tissue.

Saikosaponin-d inhibits proliferation by up-regulating autophagy via the CaMKKß-AMPK-mTOR pathway in ADPKD cells.

Autosomal dominant polycystic kidney disease (ADPKD) is a common heritable human disease. Recently, the role of repressed autophagy in ADPKD has drawn increasing attention. Here, we investigate the mechanism underlying the effect of Saikosaponin-d (SSd), a sarcoplasmic/endoplasmic reticulum Ca2+ ATPase pump (SERCA) inhibitor. We show that SSd suppresses proliferation in ADPKD cells by up-regulating autophagy. We found that treatment with SSd results in the accumulation of intracellular calcium, which in turn activates the CaMKKß-AMPK signalling cascade, inhibits mTOR signalling and induces autophagy. Conversely, we also found that treatment with an autophagy inhibitor (3-methyladenine), AMPK inhibitor (Compound C), CaMKKß inhibitor (STO-609) and intracellular calcium chelator (BAPTA/AM) could reduce autophagy puncta formation mediated by SSd. Our results demonstrated that SSd induces autophagy through the CaMKKß-AMPK-mTOR signalling pathway in ADPKD cells, indicating that SSd might be a potential therapy for ADPKD and that SERCA might be a new target for ADPKD treatment.