Sacubitril/valsartan ameliorates tubulointerstitial fibrosis by restoring mitochondrial homeostasis in diabetic kidney disease.

BACKGROUND: Tubulointerstitial fibrosis plays an important role in the progression of diabetic kidney disease (DKD). Sacubitril/valsartan (Sac/Val) exerts a robust beneficial effect in DKD. However, the potential functional effect of Sac/Val on tubulointerstitial fibrosis in DKD is still largely unclear. METHODS: Streptozotocin-induced diabetic mice were given Sac/Val or Val by intragastric administration once a day for 12 weeks. The renal function, the pathological changes of tubule injury and tubulointerstitial fibrosis, as well as mitochondrial morphology of renal tubules in mice, were evaluated. Genome-wide gene expression analysis was performed to identify the potential mechanisms. Meanwhile, human tubular epithelial cells (HK-2) were cultured in high glucose condition containing LBQ657/valsartan (LBQ/Val). Further, mitochondrial functions and Sirt1/PGC1α pathway of tubular epithelial cells were assessed by Western blot, Real-time-PCR, JC-1, MitoSOX or MitoTracker. Finally, the Sirt1 specific inhibitor, EX527, was used to explore the potential effects of Sirt1 signaling in vivo and in vitro. RESULTS: We found that Sac/Val significantly ameliorated the decline of renal function and tubulointerstitial fibrosis in DKD mice. The enrichment analysis of gene expression indicated metabolism as an important modulator in DKD mice with Sac/Val administration, in which mitochondrial homeostasis plays a pivotal role. Then, the decreased expression of Tfam and Cox IV;, as well as changes of mitochondrial function and morphology, demonstrated the disruption of mitochondrial homeostasis under DKD conditions. Interestingly, Sac/Val administration was found to restore mitochondrial homeostasis in DKD mice and in vitro model of HK-2 cells. Further, we demonstrated that Sirt1/PGC1α, a crucial pathway in mitochondrial homeostasis, was activated by Sac/Val both in vivo and in vitro. Finally, the beneficial effects of Sac/Val on mitochondrial homeostasis and tubulointerstitial fibrosis was partially abolished in the presence of Sirt1 specific inhibitor. CONCLUSIONS: Taken together, we demonstrate that Sac/Val ameliorates tubulointerstitial fibrosis by restoring Sirt1/PGC1α pathway-mediated mitochondrial homeostasis in DKD, providing a theoretical basis for delaying the progression of DKD in clinical practice.

Loss of Sirt1 promotes exosome secretion from podocytes by inhibiting lysosomal acidification in diabetic nephropathy.

Podocyte injury is a characteristic feature of diabetic nephropathy (DN). The secretion of exosomes in podocytes increases significantly in DN; however, the precise mechanisms remain poorly understood. Here, we demonstrated that Sirtuin1 (Sirt1) was significantly downregulated in podocytes in DN, which correlated negatively with increased exosome secretion. Similar results were observed in vitro. We found that lysosomal acidification in podocytes following high glucose administration was markedly inhibited, resulting in the decreased lysosomal degradation of multivesicular bodies. Mechanistically, we indicated that loss of Sirt1 contributed to the inhibited lysosomal acidification by decreasing the expression of the A subunit of the lysosomal vacuolar-type H+ ATPase proton pump (ATP6V1A) in podocytes. Overexpression of Sirt1 significantly improved lysosomal acidification with increased expression of ATP6V1A and inhibited exosome secretion. These findings suggest that dysfunctional Sirt1-mediated lysosomal acidification is the exact mechanism of increased secretion of exosomes in podocytes in DN, providing insights into potential therapeutic strategies for preventing DN progression.

Long noncoding RNA SNHG5 promotes podocyte injury via the microRNA-26a-5p/TRPC6 pathway in diabetic nephropathy.

Podocyte injury is a characteristic pathological hallmark of diabetic nephropathy (DN). However, the exact mechanism of podocyte injury in DN is incompletely understood. This study was conducted using db/db mice and immortalized mouse podocytes. High-throughput sequencing was used to identify the differentially expressed long noncoding RNAs in kidney of db/db mice. The lentiviral shRNA directed against long noncoding RNA small nucleolar RNA host gene 5 (SNHG5) or microRNA-26a-5p (miR-26a-5p) agomir was used to treat db/db mice to regulate the SNHG5/miR-26a-5p pathway. Here, we found that the expression of transient receptor potential canonical type 6 (TRPC6) was significantly increased in injured podocytes under the condition of DN, which was associated with markedly decreased miR-26a-5p. We determined that miR-26a-5p overexpression ameliorated podocyte injury in DN via binding to 3'-UTR of Trpc6, as evidenced by the markedly reduced activity of luciferase reporters by miR-26a-5p mimic. Then, the upregulated SNHG5 in podocytes and kidney in DN was identified, and it was proved to sponge to miR-26a-5p directly using luciferase activity, RNA immunoprecipitation, and RNA pull-down assay. Knockdown of SNHG5 attenuated podocyte injury in vitro, accompanied by an increased expression of miR-26a-5p and decreased expression of TRPC6, demonstrating that SNHG5 promoted podocyte injury by controlling the miR-26a-5p/TRPC6 pathway. Moreover, knockdown of SNHG5 protects against podocyte injury and progression of DN in vivo. In conclusion, SNHG5 promotes podocyte injury via the miR-26a-5p/TRPC6 pathway in DN. Our findings provide novel insights into the pathophysiology of podocyte injury and a potential new therapeutic strategy for DN.

Mild hypothermia pretreatment protects hepatocytes against ischemia reperfusion injury via down-regulating miR-122 and IGF-1R/AKT pathway.

BACKGROUND: Mild hypothermia has been well known as an effective way to reduce ischemia reperfusion injury (IRI), while the mechanisms are still unclear. More and more evidences have indicated that miRNAs should been involved in the regulation of IRI and expecially some miRNAs have shown temp-responsiveness for temperature variation. Therefore, the role of miR-122 in mild hypothermia pretreatment after IRI was investigated. METHODS: We established a LO2 cell anoxia-reoxygenation injury model to simulate liver IRI. Five groups of differently pretreated L02 cells were studied. ALT, AST and LDH as well as cell viability were measured. Flow cytometric analysis was used to evaluate the apoptosis. The expression of miR-122 was quantified by qRT-PCR. Insulin-like growth factor 1 receptor (IGF-1R), protein kinase B (p-AKT), AKT, forkhead box O3a (p-FOXO3a) and Caspase3 were examined using western blot analysis. RESULTS: We found that mild hypothermia pretreatment could reduce the hepatocellular injury and induce a significant down-regulation in miR-122 expression after IRI. However, those effects of protection were attenuated by overexpressed miR-122 blockade. We further demonstrated that down-regulation of miR-122 promoted IGF-1R translation and AKT activity, suppressed FOXO3a activity and Caspase3 expression after mild hypothermia pretreatment, which was abrogated by miR-122 mimic. CONCLUSION: Our data clearly demonstrate that mild hypothermia pretreatment can down-regulate miR-122 to protect hepatocytes against IRI through activation IGF-1R/AKT signaling pathway and inhibit cells apoptosis.

Urinary Trypsin Inhibitor Ameliorates Seawater Immersion-Induced Intestinal Mucosa Injury via Antioxidation, Modulation of NF-κB Activity, and Its Related Cytokines in Rats with Open Abdominal Injury.

Objective. To investigate the role of oxidative stress, NF-κB activity, and its related cytokines in the pathogenesis of seawater immersion after open abdominal injury (SI-OAI) and whether UTI treatment can attenuate SI-OAI induced IMI. Methods. Wistar rats were randomly divided into three groups: C group, S group, and U group. The rats in C group only suffered from anesthesia and surgical operation, whereas the rats in S group and U group received caudal vein injection of normal saline without/with 50,000 U/kg body weight of UTI. The activities of TNF-α, IL-6, SOD, MDA, ROS, NF-κB, and IκB-ß were monitored by ELISA, biochemical methods, EMSA, and Western blot, respectively. Results. The plasma inflammatory mediators and the contents of MDA, ROS, and NF-κB in intestine as well as the pathological scores in ileal mucosa were significantly increased in rats after SI-OAI, accompanied by a reduction in SOD activities and IκB-ß levels. UTI treatment significantly attenuated intestinal histopathological changes with evidence of a decrease in all of the parameters, except for upregulation of the levels of SOD and IκB-ß protein. Conclusion. UTI can attenuate SI-OAI induced IMI via inhibition of NF-κB activity, subsequently inhibiting the expression of inflammatory cytokines and by combating oxidative stress.

Dendritic fibromyxolipoma in the right inguinal and perineum regions: a case report and review of the literature.

A 32-year-old woman presented with a slow-growing, painless, subcutaneous lesion in the right inguinal and perineum regions. The mass was 24.0 cm × 10.5 cm × 5.0 cm in size, well circumscribed, mobile, and rubbery. Microscopically, the resected mass was mainly composed by a proliferation of small spindle or stellate cells, variably admixed with mature adipose tissue, embedded within an abundant myxoid and collagenized stroma. Immunohistochemically, the spindle and stellate cells were strongly positive for vimentin, CD34, and bcl-2 antibodies but not for smooth muscle actin and desmin. The tumor was diagnosed as dendritic fibromyxolipoma based on the typical findings of histology and immunohistochemistry. Clinical follow-up of 9 months after surgery revealed no evidence of recurrence. We report the first case of dendritic fibromyxolipoma in the right inguinal and perineum regions and discuss the different diagnosis. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1313680868103019.

[Gene expression profiles on three kinds of genotype hepatitis C virus core protein in Huh-7 cell line with microarray analysis].

OBJECTIVE: To analyze three kinds of genotype hepatitis C virus (HCV) core protein expressed in human hepatoma (Huh-7) cell line and to recognize HCV core proteins biological function and its pathogenic mechanism. METHODS: The Huh-7 cell expressed three kinds of core proteins were established respectively. Affymetrix human gene chip was used for identifying the gene expression dependently on Affymetrix's protocol. All genes changed by 3 or 1.5 folds between the transfected cells and a control cells were further analyzed, and annotated by using NetAffx analysis through Affymetrix website and were categorized based on their biological processes. RESULTS: The HCV-1b core protein caused 16 genes up/down-regulated expression, of which the immune response genes of PF4V1 and SPP1 were up-regulated 3.4 or 4.4 folds respectively. The HCV-2a core protein had caused the immune response gene CXCL5 and apoptosis gene BTF a down-regulated expression of 3.4 and 3.1 folds respectively, but caused the apoptosis genes of HRK and LZTS1 an up-regulated expression of 3.2 and 3.4 folds respectively. As compared with HCV 1b or 2a core protein, HCV-4b core protein caused 111 genes expression changing and it had more obvious effects on gene expression. If we applied 1.5 fold change for a comparison gene expression, a few of the same gene expression profiles might be caused by these two core proteins. CONCLUSION: The three kinds of HCV core protein should have its own expression character and be mainly shown in immune responses, signal transduction, apoptosis, etc. It should be helpful for our recognizing the HCV core protein biological function and its pathogenic mechanism.