SFN promotes renal fibrosis via binding with MYH9 in chronic kidney disease.

Chronic kidney disease (CKD) is a clinical syndrome characterized by persistent renal function decline. Renal fibrosis is the main pathological process in CKD, but an effective treatment does not exist. Stratifin (SFN) is a highly-conserved, multi-function soluble acidic protein. Therefore, this study explored the effects of SFN on renal fibrosis. First, we found that SFN was highly expressed in patients with CKD, as well as in renal fibrosis animal and cell models. Next, transforming growth factor-beta 1 (TGF-ß1) induced injury and fibrosis in human renal tubule epithelial cells, and SFN knockdown reversed these effects. Furthermore, SFN knockdown mitigated unilateral ureteral obstruction (UUO)-induced renal tubular dilatation and renal interstitial fibrosis in mice. Liquid chromatography-tandem mass spectrometry/mass spectrometry (LC-MS/MS), co-immunoprecipitation (Co-IP), and immunofluorescence co-localization assays demonstrated that SFN bound the non-muscle myosin-encoding gene, myosin heavy chain 9 (MYH9), in the cytoplasm of renal tubular epithelial cells. MYH9 knockdown also reduced Col-1 and α-SMA expression, which are fibrosis markers. Finally, silencing SFN decreased MYH9 expression, alleviating renal fibrosis. These results suggest that SFN promotes renal fibrosis in CKD by interacting with MYH9. This study may provide potential strategies for the treatment of CKD.

Ethanol depresses neurons in the lateral parabrachial nucleus by potentiating pre- and postsynaptic GABAA receptors.

As a psychoactive substance, ethanol is widely used in people's life. However, the neuronal mechanisms underlying its sedative effect remain unclear. In this study, we investigated the effects of ethanol on the lateral parabrachial nucleus (LPB), which is a novel component related to sedation. Coronal brain slices (280 µm thick) containing the LPB were prepared from C57BL/6J mice. The spontaneous firing and membrane potential of LPB neurons, and GABAergic transmission onto these neurons were recorded using whole-cell patch-clamp recordings. Drugs were applied through superfusion. The LPB neurons exhibited a regular spontaneous discharge at a rate of 1.5-3 Hz without burst firing. Brief superfusion of ethanol (30, 60, and 120 mM) concentration-dependently and reversibly suppressed the spontaneous firing of the neurons in LPB. In addition, when synaptic transmission was blocked by tetrodotoxin (TTX) (1 µM), ethanol (120 mM) caused hyperpolarization of the membrane potential. Furthermore, superfusion of ethanol markedly increased the frequency and amplitude of spontaneous and miniature inhibitory postsynaptic currents, which were abolished in the presence of the GABAA receptor (GABAA-R) antagonist picrotoxin (100 µM). In addition, the inhibitory effect of ethanol on the firing rate of LPB neurons was completely abolished by picrotoxin. Ethanol inhibits the excitability of LPB neurons in mouse slices, possibly via potentiating GABAergic transmission onto the neurons at pre- and postsynaptic sites.

Highly pathogenic coronaviruses and the kidney.

Since the end of 2019, the outbreak of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has triggered a pneumonia epidemic, posing a significant public health challenge in 236 countries, territories, and regions worldwide. Clinically, in addition to the symptoms of pulmonary infection, many patients with SARS-CoV-2 infections, especially those with a critical illness, eventually develop multiple organ failure in which damage to the kidney function is common, ultimately leading to severe consequences such as increased mortality and morbidity. To date, three coronaviruses have set off major global public health security incidents: Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV), Middle East Respiratory Syndrome Coronavirus (MERS-CoV), and SARS-CoV-2. Among the diseases caused by the coronaviruses, the coronavirus disease 2019 (COVID-19) has been the most impactful and harmful. Similar to with SARS-CoV-2 infections, previous studies have shown that kidney injury is also common and prominent in patients with the two other highly pathogenic coronaviruses. Therefore, in this review, we aimed to comprehensively summarize the epidemiological and clinical characteristics of these three pandemic-level infections, provide a deep analysis of the potential mechanism of COVID-19 in various types of kidney diseases, and explore the causes of secondary kidney diseases of SARS-CoV-2, so as to provide a reference for further research and the clinical prevention of kidney damage caused by coronaviruses.

The role of discoid domain receptor 1 on renal tubular epithelial pyroptosis in diabetic nephropathy.

Pyroptosis, a form of cell death associated with inflammation, is known to be involved in diabetic nephropathy (DN), and discoid domain receptor 1 (DDR1), an inflammatory regulatory protein, is reported to be associated with diabetes. However, the mechanism underlying DDR1 regulation and pyroptosis in DN remains unknown. We aimed to investigate the effect of DDR1 on renal tubular epithelial cell pyroptosis and the mechanism underlying DN. In this study, we used high glucose (HG)-treated HK-2 cells and rats with a single intraperitoneal injection of streptozotocin as DN models. Subsequently, the expression of pyroptosis-related proteins (cleaved caspase-1, GSDMD-N, Interleukin-1ß [IL-1ß], and interleukin-18 [IL-18]), DDR1, phosphorylated NF-κB (p-NF-κB), and NLR family pyrin domain-containing 3 (NLRP3) inflammasomes were determined through Western blotting. IL-1ß and IL-18 levels were determined using ELISA. The rate of pyroptosis was assessed by propidium iodide (PI) staining. The results revealed upregulated expression of pyroptosis-related proteins and increased concentration of IL-1ß and IL-18, accompanied by DDR1, p-NF-κB, and NLRP3 upregulation in DN rat kidney tissues and HG-treated HK-2 cells. Moreover, DDR1 knockdown in the background of HG treatment resulted in inhibited expression of pyroptosis-related proteins and attenuation of IL-1ß and IL-18 production and PI-positive cell frequency via the NF-κB/NLRP3 pathway in HK-2 cells. However, NLRP3 overexpression reversed the effect of DDR1 knockdown on pyroptosis. In conclusion, we demonstrated that DDR1 may be associated with pyroptosis, and DDR1 knockdown inhibited HG-induced renal tubular epithelial cell pyroptosis. The NF-κB/NLRP3 pathway is probably involved in the underlying mechanism of these findings.

Predicting medication nonadherence risk in the Chinese type 2 diabetes mellitus population - establishment of a new risk nomogram model: a retrospective study.

OBJECTIVE: To investigate the risk factors of medication nonadherence in patients with type 2 diabetes mellitus (T2DM) and to establish a risk nomogram model. METHODS: This retrospective study enrolled patients with T2DM, which were divided into two groups based on their scores on the Morisky Medication Adherence scale. Univariate and multivariate logistic regression analyses were used to screen for independent risk factors for medication nonadherence. A risk model was then established using a nomogram. The accuracy of the prediction model was evaluated using centrality measurement index and receiver operating characteristic curves. Internal verification was evaluated using bootstrapping validation. RESULTS: A total of 338 patients with T2DM who included in the analysis. Logistic regression analysis showed that the educational level, monthly per capita income, drug affordability, the number of drugs used, daily doses of drugs and the time spent taking medicine were all independent risk factors for medication nonadherence. Based on these six risk factors, a nomogram model was established to predict the risk of medication nonadherence, which was shown to be very reliable. Bootstrapping validated the nonadherence nomogram model for patients with T2DM. CONCLUSIONS: This nomogram model could be used to evaluate the risks of drug nonadherence in patients with T2DM.

[Screening potential Chinese materia medica and their monomers for treatment diabetic nephropathy based on caspase-1-mediated pyroptosis].

OBJECTIVE: To screen potential traditional Chinese medicine and their active monomer ingredients for treatment of diabetic nephropathy (DN) through the mechanism of caspase-1-mediated pyroptosis. METHODS: Using the Chinese Medicine System Pharmacology Analysis Platform (TCMSP), we screened traditional Chinese drugs and their active monomer components targeting caspase-1, and searched for the potential gene targets of the monomer components using GeneCards database. Cytoscape was used to construct the monomer compound-gene target network. Gene ontology (GO) functional enrichment analysis and Kyoto Gene and Gene Encyclopedia (KEGG) pathway enrichment analysis were used to predict the molecular mechanism of the screened traditional Chinese medicine and monomers. In SD rat models of diabetic mellitus (DM), we tested the therapeutic effect of ginsenoside Rh2 (daily dose of 20 mg/kg for 12 weeks) by examining renal pathology with HE staining and detecting the expressions of pyroptosis marker proteins caspase-1, GSDMD, IL-1ß and IL-18 in the renal tissues using Western blotting, the serum levels of IL-1ß and IL-18 and activities of cathepsin B and cathepsin L. RESULTS: Ginsenoside Rh2 could effectively dock with caspase-1 molecule. Fourteen targets were identified in ginsenoside Rh2 target network. GO function enrichment analysis revealed 27 GO terms associated with molecular function (4 terms), cell component (10 terms) and biological process (13 terms). KEGG pathyway enrichment analysis identified 4 signaling pathways involving lysosomes, glycosaminoglycan degradation, galactose metabolism, and sphingolipid metabolism pathways. In the animal experiment, treatment with ginsenoside Rh2 significantly alleviated renal pathologies and down-regulated the expressions of pyroptosis marker proteins (cleaved caspase-1, GSDMD-N, IL-1ß and IL-18) (P < 0.05 or 0.01), lowered serum levels of IL-1ß and IL-18 (P < 0.01), and enhanced the activities of cathepsin B and cathepsin L in the serum of the diabetic rats. CONCLUSIONS: Ginsenoside Rh2 may inhibit caspase-1-mediated pyroptosis through the lysosome pathway to improve kidney damages in rat models of DN.

Upregulation of mesencephalic astrocyte-derived neurotrophic factor in glial cells is associated with ischemia-induced glial activation.

BACKGROUND: Mesencephalic astrocyte-derived neurotrophic factor (MANF), a 20 kDa secreted protein, was originally derived from a rat mesencephalic type-1 astrocyte cell line. MANF belongs to a novel evolutionally conserved family of neurotrophic factors along with conserved dopamine neurotrophic factor. In recent years, ever-increasing evidence has shown that both of them play a remarkable protective role against various injuries to neurons in vivo or in vitro. However, the characteristics of MANF expression in the different types of glial cells, especially in astrocytes, remain unclear. METHODS: The model of focal cerebral ischemia was induced by rat middle cerebral artery occlusion. Double-labeled immunofluorescent staining was used to identify the types of neural cells expressing MANF. Primarily cultured glial cells were used to detect the response of glial cells to endoplasmic reticulum stress stimulation. Propidium iodide staining was used to determine dead cells. Reverse transcription PCR and western blotting were used to detect the levels of mRNA and proteins. RESULTS: We found that MANF was predominantly expressed in neurons in both normal and ischemic cortex. Despite its name, MANF was poorly expressed in glial cells, including astrocytes, in normal brain tissue. However, the expression of MANF was upregulated in the glial cells under focal cerebral ischemia, including the astrocytes. This expression was also induced by several endoplasmic reticulum stress inducers and nutrient deprivation in cultured primary glial cells. The most interesting phenomenon observed in this study was the pattern of MANF expression in the microglia. The expression of MANF was closely associated with the morphology and state of microglia, accompanied by the upregulation of BIP/Grp78. CONCLUSIONS: These results indicate that MANF expression was upregulated in the activated glial cells, which may contribute to the mechanism of ischemia-induced neural injury.

Induction profile of MANF/ARMET by cerebral ischemia and its implication for neuron protection.

Cerebral ischemia-induced accumulation of unfolded proteins in vulnerable neurons triggers endoplasmic reticulum (ER) stress. Arginine-rich, mutated in early stage tumors (ARMET) is an ER stress-inducible protein and upregulated in the early stage of cerebral ischemia. The purposes of this study were to investigate the characteristics and implications of ARMET expression induced by focal cerebral ischemia. Focal cerebral ischemia in rats was induced by right middle cerebral artery occlusion with a suture; ischemic lesions were assessed by magnetic resonance imaging and histology; neuronal apoptosis was determined by TUNEL staining; the expressions of proteins were measured by immunohistochemistry, immunofluorescent labeling, and Western blotting. ARMET was found to be extensively upregulated in ischemic regions in a time-dependent manner. The expression of ARMET was neuronal in all examined structures in response to the ischemic insult. We also found that ARMET expression is earlier and more sensitive to ischemic stimulation than C/EBP homologous protein (CHOP). ER stress agent tunicamycin induced ARMET and CHOP expressions in the primary cultured neurons. Treatment with recombinant human ARMET promoted neuron proliferation and prevented from neuron apoptosis induced by tunicamycin. These results suggest that cerebral ischemia-induced ARMET expression may be protective to the neurons.