Role of MKK3-p38 MAPK signalling in the development of type 2 diabetes and renal injury in obese db/db mice

Huanglian-banxia promotes gastric motility of diabetic rats by modulating brain-gut neurotransmitters through MAPK signaling pathway

BACKGROUND

Gastric motility disorder is an increasingly common problem among people with diabetes. Neurotransmitters have been recognized as critical regulators in the process of gastric motility. Previous study has shown that herb pair huanglian-banxia (HL-BX) can improve gastric motility, but the underlying mechanism is still unclear. The aim of this study was to further investigate the role of HL-BX in modulating brain-gut neurotransmission to promote gastric motility in diabetic rats, and to explore its possible mechanism.

METHODS

The diabetic rats were divided into five groups. Gastric emptying rate, intestinal propulsion rate, body weight, and average food intake were determined. Substance P (SP), 5- hydroxytryptamine (5-HT), and glucagon-like peptide -1 (GLP-1) in the serum were measured by enzyme-linked immunosorbent assay. Dopamine (DA) and norepinephrine (NE) in the brain were analyzed by high-pressure liquid chromatography with a fluorescence detector. Protein expression of the tissues in the stomach and brain was determined by Western blot.

KEY RESULTS

HL-BX reduced average food intake significantly, increased body weight, and improved gastric emptying rate and intestinal propulsion rate. HL-BX administration caused a significant increase in SP, GLP-1, and 5-HT, but a significant decrease in DA and NE. Interestingly, HL-BX regulated simultaneously the different expressions of MAPK and its downstream p70S6K/S6 signaling pathway in the stomach and brain. Moreover, berberine exhibited a similar effect to HL-BX.

CONCLUSIONS

These results indicated that HL-BX promoted gastric motility by regulating brain-gut neurotransmitters through the MAPK signaling pathway. HL-BX and MAPK provide a potential therapeutic option for the treatment of gastroparesis.

The Perfect Cup? Coffee-Derived Polyphenols and Their Roles in Mitigating Factors Affecting Type 2 Diabetes Pathogenesis

Type 2 diabetes (T2D) is a growing health concern with an estimated 462 million people having been diagnosed worldwide. T2D is characterized by chronically elevated blood glucose and insulin resistance, which culminate in a diminished function of the β-cell mass in its later stages. This can be perpetuated by and result in inflammation, excess reactive oxygen species production, obesity, and the dysregulation of multiple cellular pathways. Many naturally occurring small molecules have been investigated in terms of their roles in modulating glucose homeostasis and β-cell function. Many of these compounds can be found in commonly used sources of food and drink. Interestingly, a correlation has been observed between coffee consumption and T2D incidence. However, the specific compounds responsible for this correlation and their mechanisms are still somewhat undetermined. This paper reviews recent research findings on the effects of several polyphenols that are either found in coffee or are metabolites of compounds found in coffee (enterodiol, enterolactone, matairesinol, secoisolariciresinol, kaempferol, quercetin, and chlorogenic acid) on glucose homeostasis and health complications associated with glucose dysregulation, with a special emphasis on their potential anti-diabetic effects. The factors that affect polyphenol content in coffee are also addressed.

Recent advances in medicinal and edible homologous plant polysaccharides: Preparation, structure and prevention and treatment of diabetes

Medicinal and edible homologs (MEHs) can be used in medicine and food. The National Health Commission announced that a total of 103 kinds of medicinal and edible homologous plants (MEHPs) would be available by were available in 2023. Diabetes mellitus (DM) has become the third most common chronic metabolic disease that seriously threatens human health worldwide. Polysaccharides, the main component isolated from MEHPs, have significant antidiabetic effects with few side effects. Based on a literature search, this paper summarizes the preparation methods, structural characterization, and antidiabetic functions and mechanisms of MEHPs polysaccharides (MEHPPs). Specifically, MEHPPs mainly regulate PI3K/Akt, AMPK, cAMP/PKA, Nrf2/Keap1, NF-κB, MAPK and other signaling pathways to promote insulin secretion and release, improve glycolipid metabolism, inhibit the inflammatory response, decrease oxidative stress and regulate intestinal flora. Among them, 16 kinds of MEHPPs were found to have obvious anti-diabetic effects. This article reviews the prevention and treatment of diabetes and its complications by MEHPPs and provides a basis for the development of safe and effective MEHPP-derived health products and new drugs to prevent and treat diabetes.

The Influence of Betulin Derivatives EB5 and ECH147 on the Expression of Selected TGFβ Superfamily Genes, TGFβ1, GDF15 and BMP2, in Renal Proximal Tubule Epithelial Cells

Betulin derivatives are proposed to serve as an alternative to the drugs already established in oncologic treatment. Drug-induced nephrotoxicity leading to acute kidney injury frequently accompanies cancer treatment, and thus there is a need to research the effects of betulin derivatives on renal cells. The objective of our study was to assess the influence of the betulin derivatives 28-propynylobetulin (EB5) and 29-diethoxyphosphoryl-28-propynylobetulin (ECH147) on the expression of TGFβ1, BMP2 and GDF15 in renal proximal tubule epithelial cells (RPTECs) cultured in vitro. The changes in mRNA expression and copy numbers were assessed using real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR) and the standard curve method, respectively. An enzyme-linked immunosorbent assay (ELISA) was used to evaluate the effect of the betulin derivatives on the protein concentration in the culture media's supernatant. The assessment of the betulin derivatives' influence on gene expression demonstrated that the mRNA level and protein concentration did not always correlate with each other. Each of the tested compounds affected the mRNA expression. The RT-qPCR analyses showed that EB5 and ECH147 induced effects similar to those of betulin or cisplatin and resulted in a decrease in the mRNA copy number of all the analyzed genes. The ELISA demonstrated that EB5 and ECH147 elevated the protein concentration of TGFβ1 and GDF15, while the level of BMP2 decreased. The concentration of the derivatives used in the treatment was crucial, but the effects did not always exhibit a simple linear dose-dependent relationship. Betulin and its derivatives, EB5 and ECH147, influenced the gene expression of TGFβ1, BMP2 and GDF15 in the renal proximal tubule epithelial cells. The observed effects raise the question of whether treatment with these compounds could promote the development of renal fibrosis.

The Molecular Mechanism of Renal Tubulointerstitial Inflammation Promoting Diabetic Nephropathy

Diabetic nephropathy (DN) is a common complication affecting many diabetic patients, leading to end-stage renal disease. However, its pathogenesis still needs to be fully understood to enhance the effectiveness of treatment methods. Traditional theories are predominantly centered on glomerular injuries and need more explicit explanations of recent clinical observations suggesting that renal tubules equally contribute to renal function and that tubular lesions are early features of DN, even occurring before glomerular lesions. Although the conventional view is that DN is not an inflammatory disease, recent studies indicate that systemic and local inflammation, including tubulointerstitial inflammation, contributes to the development of DN. In patients with DN, intrinsic tubulointerstitial cells produce many proinflammatory factors, leading to medullary inflammatory cell infiltration and activation of inflammatory cells in the interstitial region. Therefore, understanding the molecular mechanism of renal tubulointerstitial inflammation contributing to DN injury is of great significance and will help further identify key factors regulating renal tubulointerstitial inflammation in the high glucose environment. This will aid in developing new targets for DN diagnosis and treatment and expanding new DN treatment methods.

Exploring lncRNAs associated with human pancreatic islet cell death induced by transfer of adoptive lymphocytes in a humanized mouse model

Background

Long noncoding RNA (lncRNA)-mediated posttranscriptional and epigenetic landscapes of gene regulation are associated with numerous human diseases. However, the regulatory mechanisms governing human β-cell function and survival remain unknown. Owing to technical and ethical constraints, studying the direct role of lncRNAs in β-cell function and survival in humans in vivo is difficult. Therefore, we utilized humanized mice with human islets to investigate lncRNA expression using whole transcriptome shotgun sequencing. Our study aimed to characterize lncRNAs that may be crucial for human islet cell function and survival.

Methods

Human β-cell death was induced in humanized mice engrafted with functional human islets. Using these humanized mice harboring human islets with induced β-cell death, we investigated lncRNA expression through whole transcriptome shotgun sequencing. Additionally, we systematically identified, characterized, and explored the regulatory functions of lncRNAs that are potentially important for human pancreatic islet cell function and survival.

Results

Human islet cell death was induced in humanized mice engrafted with functional human islets. RNA sequencing analysis of isolated human islets, islet grafts from humanized mice with and without induced cell death, revealed aberrant expression of a distinct set of lncRNAs that are associated with the deregulated mRNAs important for cellular processes and molecular pathways related to β-cell function and survival. A total of 10 lncRNA isoforms (SCYL1-1:22, POLG2-1:1, CTRB1-1:1, SRPK1-1:1, GTF3C5-1:1, PPY-1:1, CTRB1-1:5, CPA5-1:1, BCAR1-2:1, and CTRB1-1:4) were identified as highly enriched and specific to human islets. These lncRNAs were deregulated in human islets from donors with different BMIs and with type 2 diabetes (T2D), as well as in cultured human islets with glucose stimulation and induced cell death induced by cytokines. Aberrant expression of these lncRNAs was detected in the exosomes from the medium used to culture islets with cytokines.

Conclusion

Islet-enriched and specific human lncRNAs are deregulated in human islet grafts and cultured human islets with induced cell death. These lncRNAs may be crucial for human β-cell function and survival and could have an impact on identifying biomarkers for β-cell loss and discovering novel therapeutic targets to enhance β-cell function and survival.

Galantamine improves glycemic control and diabetic nephropathy in Leprdb/db mice

Galantamine, a centrally acting acetylcholinesterase inhibitor, has been shown to attenuate inflammation and insulin resistance in patients with metabolic syndrome. We investigated the effects of galantamine on glycemic control and development of diabetic nephropathy (DN) in Leprdb/db mice. Galantamine significantly reduced food intake, body weight, blood glucose and HbA1c levels. Insulin resistance (HOMA-IR, QUICKI), HOMA-β and elevations in plasma inflammatory cytokine levels (TNF-α, IL-6 and HMGB-1) were all attenuated by galantamine. Galantamine also ameliorated diabetes-induced kidney injury as evidenced by improvements in renal function (BUN, creatinine, albuminuria), histologic injury and apoptosis. Improved glycemic control and nephropathy were associated with increased circulating GLP-1, decreased renal P-38 MAPK and caspase-1 activation and reduced SGLT-2 expression. These findings provide insights into the mechanisms by which galantamine improves glycemic control and attenuates DN in the Leprdb/db mouse model.

Plasma proteins and onset of type 2 diabetes and diabetic complications: Proteome-wide Mendelian randomization and colocalization analyses

We conduct proteome-wide Mendelian randomization and colocalization analyses to decipher the associations of blood proteins with the risk of type 2 diabetes and diabetic complications. Genetic data on plasma proteome are obtained from 54,306 UK Biobank participants and 35,559 Icelanders. Summary-level data on type 2 diabetes are obtained from the DIAGRAM (DIAbetes Genetics Replication And Meta-analysis consortium) consortium (74,124 cases) and FinnGen study (33,043 cases). Data on 10 diabetic complications are obtained from FinnGen and corresponding studies. Among 1,886 proteins, genetically predicted levels of 47 plasma proteins are associated with type 2 diabetes. Eleven of these proteins have strong support of colocalization. Seventeen proteins are associated with at least one diabetic complication, although a few have colocalization support. HLA-DRA, AGER, HSPA1A, and HSPA1B are associated with most microvascular complications. This study reveals causal proteins for the onset of type 2 diabetes and diabetic complications, which enhances the understanding of molecular etiology and development of therapeutics.

Microcystin-LR-Exposure-Induced Kidney Damage by Inhibiting MKK6-Mediated Mitophagy in Mice

Previous studies have reported that microcystin-LR (MC-LR) levels are highly correlated with abnormal renal function indicators, suggesting that MC-LR is an independent risk factor for kidney damage. However, the evidence for the exact regulation mechanism of MC-LR on kidney damage is still limited, and further in-depth exploration is needed. In addition, the mitochondria-related mechanism of MC-LR leading to kidney damage has not been elucidated. To this end, the present study aimed to further explore the mechanism of mitophagy related to kidney damage induced by MC-LR through in vitro and in vivo experiments. Male C57BL/6 mice were fed with a standard rodent pellet and exposed daily to MC-LR (20 μg/kg·bw) via intraperitoneal injections for 7 days. Moreover, HEK 293 cells were treated with MC-LR (20 μM) for 24 h. The histopathological results exhibited kidney damage after MC-LR exposure, characterized by structurally damaged nephrotomies, with inflammatory cell infiltration. Similarly, a significant increase in renal interstitial fibrosis was observed in the kidneys of MC-LR-treated mice compared with those of the control group (CT) mice. MC-LR exposure caused impaired kidney function, with markedly increased blood urea nitrogen (BUN), creatinine (Cr), and uric acid (UA) levels in mice. Ultrastructural analysis exhibited obviously swollen, broken, and disappearing mitochondrial crests, and partial mitochondrial vacuoles in the MC-LR-treated HEK 293 cells. The Western blotting results demonstrated that exposure to MC-LR significantly increased the protein expressions of MKK6, p-p38, and p62, while the expression of mitophagy-related proteins was significantly inhibited in the kidneys of mice and HEK293 cells, including parkin, TOM20, and LC3-II, indicating the inhibition of mitophagy. Therefore, our data suggest that the inhibition of MKK6-mediated mitophagy might be the toxicological mechanism of kidney toxicity in mice with acute exposure to MC-LR.

Gramine protects against pressure overload-induced pathological cardiac hypertrophy through Runx1-TGFBR1 signaling

BACKGROUND

Gramine, also named 3-(N,N-dimethylaminomethyl) indole, is a indole alkaloid. It is mainly extracted from various natural raw plants. Despite being the simplest 3-aminomethylindole, Gramine has broad pharmaceutical and therapeutic effects, such as vasodilatation, antioxidation, mitochondrial bioenergetics-related effects, and angiogenesis via modulation of TGFβ signaling. However, there is little information available about Gramine's role in heart disease, especially pathological cardiac hypertrophy.

PURPOSE

To investigate Gramine's effect on pathological cardiac hypertrophy and clarify the mechanisms behind its action.

METHODS

In the in vitro experiment, Gramine (25 μM or 50 μM) was used to investigate its role in Angiotensin II-induced primary neonatal rat cardiomyocytes (NRCMs) hypertrophy. In the in vivo experiment, Gramine (50 mg/kg or 100 mg/kg) was administrated to investigate its role in transverse aortic constriction (TAC) surgery mice. Additionally, we explored the mechanisms underlying these roles through Western blot, Real-time PCR, genome-wide transcriptomic analysis, chromatin immunoprecipitation and molecular docking studies.

RESULTS

The in vitro data demonstrated that Gramine treatment obviously improved primary cardiomyocyte hypertrophy induced by Angiotensin II, but had few effects on the activation of fibroblasts. The in vivo experiments indicated that Gramine significantly mitigated TAC-induced myocardial hypertrophy, interstitial fibrosis and cardiac dysfunction. Mechanistically, RNA sequencing and further bioinformatics analysis demonstrated that transforming growth factor β (TGFβ)-related signaling pathway was enriched significantly and preferentially in Gramine-treated mice as opposed to vehicle-treated mice during pathological cardiac hypertrophy. Moreover, this cardio-protection of Gramine was found to mainly involved in TGFβ receptor 1 (TGFBR1)- TGFβ activated kinase 1 (TAK1)-p38 MAPK signal cascade. Further exploration showed that Gramine restrained the up-regulation of TGFBR1 by binding to Runt-related transcription factor 1 (Runx1), thereby alleviating pathological cardiac hypertrophy.

CONCLUSION

Our findings provided a substantial body of evidence that Gramine possessed a potential druggability in pathological cardiac hypertrophy via suppressing the TGFBR1-TAK1-p38 MAPK signaling axis through interaction with transcription factor Runx1.

Metaflammation in glucolipid metabolic disorders: Pathogenesis and treatment

The public health issue of glucolipid metabolic disorders (GLMD) has grown significantly, posing a grave threat to human wellness. Its prevalence is rising yearly and tends to affect younger people. Metaflammation is an important mechanism regulating body metabolism. Through a complicated multi-organ crosstalk network involving numerous signaling pathways such as NLRP3/caspase-1/IL-1, NF-B, p38 MAPK, IL-6/STAT3, and PI3K/AKT, it influences systemic metabolic regulation. Numerous inflammatory mediators are essential for preserving metabolic balance, but more research is needed to determine how they contribute to the co-morbidities of numerous metabolic diseases. Whether controlling the inflammatory response can influence the progression of GLMD determines the therapeutic strategy for such diseases. This review thoroughly examines the role of metaflammation in GLMD and combs the research progress of related therapeutic approaches, including inflammatory factor-targeting drugs, traditional Chinese medicine (TCM), and exercise therapy. Multiple metabolic diseases, including diabetes, non-alcoholic fatty liver disease (NAFLD), cardiovascular disease, and others, respond therapeutically to anti-inflammatory therapy on the whole. Moreover, we emphasize the value and open question of anti-inflammatory-based means for treating GLMD.

Dual inhibitors of ASK1 and PDK1 kinases: Design, synthesis, molecular docking and mechanism studies of N-benzyl pyridine-2-one containing derivatives as anti-fibrotic agents

Utilizing fragment-based hybrid designing strategies, 24 N-benzyl pyridine-2-one containing derivatives were synthesized by successfully incorporating 6-(4H-1,2,4-triazol-3-yl) pyridin-2-amine of scaffold of ASK1 inhibitor (GS-444217). These newly synthesized compounds were screened in cell-free ASK1 and PDK1 kinase and cellular vitality assays. Among all compounds tested, both 21c and 21d displayed single digit potency of 9.13, 1.73 nM in inhibiting ASK1, and exhibited excellent enzyme inhibitory activity against PDK1 (the inhibition rates at 10 μM were 13.63% and 23.80%, respectively). Specifically, both compounds inhibited the TGF-β1 induced fibrotic response and blocked the up-regulated protein expression levels of ASK1-p38/JNK signaling pathways and possessed the potency in reducing PDK1/Akt phosphorylation. The results herein showed the potential lead characteristics of 21c or 21d as dual inhibitors ASK1/PDK1 kinases.

GTS-21, a selective alpha7 nicotinic acetylcholine receptor agonist, ameliorates diabetic nephropathy in Leprdb/db mice

Diabetic nephropathy (DN) is a serious complicating factor in human type 2 diabetes mellitus (T2DM), and it commonly results in end-stage renal disease (ESRD) that requires kidney dialysis. Here, we report that the α7 nicotinic acetylcholine receptor (α7nAChR) agonist GTS-21 exerts a novel anti-inflammatory action to ameliorate DN, as studied using an inbred strain of Leprdb/db mice in which hyperglycemia and obesity co-exist owing to defective leptin receptor (Lepr) signaling. For this analysis, GTS-21 was administered to 10-12 week-old male and female mice as a 4 mg/kg intraperitoneal injection, twice-a-day, for 8 weeks. Kidney function and injury owing to DN were monitored by determination of plasma levels of BUN, creatinine, KIM-1 and NGAL. Histologic analysis of glomerular hypertrophy and mesangial matrix expansion were also used to assess DN in these mice. Concurrently, renal inflammation was assessed by measuring IL-6 and HMGB1, while also quantifying renal cell apoptosis, and apoptotic signaling pathways. We found that Leprdb/db mice exhibited increased markers of BUN, creatinine, NGAL, KIM-1, IL-6, cytochrome C, and HMGB-1. These abnormalities were also accompanied by histologic kidney injury (mesangial matrix expansion and apoptosis). Remarkably, all such pathologies were significantly reduced by GTS-21. Collectively, our results provide new evidence that the α7nAChR agonist GTS-21 has the ability to attenuate diabetes-induced kidney injury. Additional studies are warranted to further investigate the involvement of the vagal cholinergic anti-inflammatory reflex pathway (CAP) in ameliorating diabetic nephropathy.

A Cyclopentanone Compound Attenuates the Over-Accumulation of Extracellular Matrix and Fibrosis in Diabetic Nephropathy via Downregulating the TGF-β/p38MAPK Axis

Excessive accumulation of the extracellular matrix (ECM) is a crucial pathological process in chronic kidney diseases, such as diabetic nephropathy, etc. The underlying mechanisms of how to decrease ECM deposition to improve diabetic nephropathy remain elusive. The present study investigated whether cyclopentanone compound H8 alleviated ECM over-deposition and fibrosis to prevent and treat diabetic nephropathy. HK-2 cell viability after treatment with H8 was measured by an MTT assay. ECM alterations and renal fibrosis were identified in vitro and in vivo. A pharmacological antagonist was used to detect associations between H8 and the p38 mitogen-activated protein kinase (p38MAPK) signaling pathway. H8 binding was identified through computer simulation methods. Studies conducted on high glucose and transforming growth factor β1 (TGF-β1)-stimulated HK-2 cells revealed that the p38MAPK inhibitor SB 202190 and H8 had similar pharmacological effects. In addition, excessive ECM accumulation and fibrosis in diabetic nephropathy were remarkably improved after H8 administration in vivo and in vitro. Finally, the two molecular docking models further proved that H8 is a specific p38MAPK inhibitor that forms a hydrogen bond with the LYS-53 residue of p38MAPK. The cyclopentanone compound H8 alleviated the over-deposition of ECM and the development of fibrosis in diabetic nephropathy by suppressing the TGF-β/p38MAPK axis.

Dual specificity phosphatase 22 suppresses mesangial cell hyperproliferation, fibrosis, inflammation and the MAPK signaling pathway in diabetic nephropathy

Dual specificity phosphatase 22 (DUSP22) regulates fibrosis and inflammation, which may be implicated in the development of diabetic nephropathy (DN). Hence, the current study aimed to assess the effect of DUSP22 on cell proliferation, apoptosis, fibrosis and inflammation in mouse mesangial cell line (SV40-MES13) under both high glucose (HG) and low glucose (LG) conditions. SV40-MES13 cells were treated with HG and LG, then HG-group cells were transfected with DUSP22 overexpression and control plasmids, meanwhile LG-group cells were transfected with DUSP22 and control siRNAs. Then, cell proliferation using Cell Counting Kit-8, cell apoptosis by TUNEL assay, protein expression using western blotting, inflammatory cytokines using ELISA and RNA using reverse transcription-quantitative PCR were determined. DUSP22 mRNA and protein were decreased in SV40-MES13 cells under the HG condition compared with those under the LG condition. Under the HG condition, DUSP22 overexpression suppressed SV40-MES13 cell proliferation at 48 and 72 h as well as Bcl2, but it facilitated TUNEL-reflected apoptotic rate and cleaved-caspase-3; besides, DUSP22 overexpression restrained proteins of fibronectin 1, collagen I, transforming growth factor beta 1, and their corresponding mRNAs. As to the inflammation, DUSP22 overexpression downregulated TNF-α, IL-1β, IL-6 and IL-12 under the HG condition. By contrast, DUSP22 siRNA promoted SV40-MES13 cell proliferation, fibrosis and inflammation, but attenuated apoptosis in SV40-MES13 cells under the LG condition. Additionally, DUSP22 overexpression inactivated phosphorylated (p)-ERK, p-JNK, and p-P38 in HG-treated SV40-MES13 cells; differently, DUSP22 small interfering RNA facilitated them under the LG condition. In conclusion, DUSP22 suppresses HG-induced mesangial cell hyperproliferation, fibrosis, inflammation and the MAPK pathway, implying its potency in DN treatment.

Exploring the Active Ingredients and Mechanism of Action of Huanglian Huazhuo Capsule for the Treatment of Obese Type-2 Diabetes Mellitus Based on Using Network Pharmacology and Molecular Docking

Background

Obese type 2 diabetes mellitus (obese T2DM) is one of the prime diseases that endangers human health. Clinical studies have confirmed the ability of the Huanglian Huazhuo capsule to treat obese T2DM; however, its mechanism of action is still unclear. In this study, effects and mechanisms of the Huanglian Huazhuo capsule in obese T2DM were systematically investigated using network pharmacology and molecular docking techniques.

Methods

The active ingredients and targets of the Huanglian Huazhuo capsule were extracted from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP). Obese T2DM diabetes-related targets were retrieved from a geographic dataset combined with a gene card database. A protein-protein interaction (PPI) network was constructed to screen core targets. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted using Database for Annotation Visualization and Integrated Discovery (DAVID). Interactions between potential targets and active compounds were assessed using molecular docking. Molecular docking was performed on the best core protein complexes obtained using molecular docking.

Results

A total of 89 and 108 active ingredients and targets, respectively, were identified. Seven core targets were obtained using a topological analysis of the PPI network. The GO and KEGG pathway enrichment analyses showed that the effects of the Huanglian Huazhuo capsules were mediated by inflammation, lipid response, oxidative stress-related genes, and HIF-1 and IL-17 signaling pathways. Good binding ability was observed between the active compounds and screened targets using molecular docking.

Conclusions

The active ingredients, potential targets, and pathways of the Huanglian Huazhuo capsule for the treatment of obese T2DM were successfully predicted, providing a new strategy for further investigation of its molecular mechanisms. In addition, the potential active ingredients provide a reliable source for drug screening in obese T2DM.

Signaling pathways in obesity: mechanisms and therapeutic interventions

Obesity is a complex, chronic disease and global public health challenge. Characterized by excessive fat accumulation in the body, obesity sharply increases the risk of several diseases, such as type 2 diabetes, cardiovascular disease, and nonalcoholic fatty liver disease, and is linked to lower life expectancy. Although lifestyle intervention (diet and exercise) has remarkable effects on weight management, achieving long-term success at weight loss is extremely challenging, and the prevalence of obesity continues to rise worldwide. Over the past decades, the pathophysiology of obesity has been extensively investigated, and an increasing number of signal transduction pathways have been implicated in obesity, making it possible to fight obesity in a more effective and precise way. In this review, we summarize recent advances in the pathogenesis of obesity from both experimental and clinical studies, focusing on signaling pathways and their roles in the regulation of food intake, glucose homeostasis, adipogenesis, thermogenesis, and chronic inflammation. We also discuss the current anti-obesity drugs, as well as weight loss compounds in clinical trials, that target these signals. The evolving knowledge of signaling transduction may shed light on the future direction of obesity research, as we move into a new era of precision medicine.

Increased LRG1 Levels in Overweight and Obese Adolescents and Its Association with Obesity Markers, Including Leptin, Chemerin, and High Sensitivity C-Reactive Protein

Leucine-rich α-2 glycoprotein1 (LRG1) is a member of the leucine-rich repeat (LRR) family that is implicated in multiple diseases, including cancer, aging, and heart failure, as well as diabetes and obesity. LRG1 plays a key role in diet-induced hepatosteatosis and insulin resistance by mediating the crosstalk between adipocytes and hepatocytes. LRG1 also promotes hepatosteatosis by upregulating de novo lipogenesis in the liver and suppressing fatty acid β-oxidation. In this study, we investigated the association of LRG1 with obesity markers, including leptin and other adipokines in adolescents (11−14 years; n = 425). BMI-for-age classification based on WHO growth charts was used to define obesity. Plasma LRG1 was measured by ELISA, while other markers were measured by multiplexing assay. Median (IQR) of LRG1 levels was higher in obese (30 (25, 38) µg/mL) and overweight (30 (24, 39) µg/mL) adolescents, compared to normal-weight participants (27 (22, 35) µg/mL). The highest tertile of LRG1 had an OR [95% CI] of 2.55 [1.44, 4.53] for obesity. LRG1 was positively correlated to plasma levels of high sensitivity c-reactive protein (HsCRP) (ρ = 0.2), leptin (ρ = 0.2), and chemerin (ρ = 0.24) with p < 0.001. Additionally, it was positively associated with plasma level of IL6 (ρ = 0.17) and IL10 (ρ = 0.14) but not TNF-α. In conclusion, LRG1 levels are increased in obese adolescents and are associated with increased levels of adipogenic markers. These results suggest the usefulness of LRG1 as an early biomarker for obesity and its related pathologies in adolescents.

The Role of Vitamin D in Diabetic Nephropathy: A Translational Approach

According to several animal and human studies, vitamin D appears to play a significant role in the development of diabetic nephropathy. However, the possible renoprotective effect of vitamin D and its influence on the reversal of already existing renal damage remains doubtful. At this moment, there are a few hypotheses concerning the underlying molecular and genetic mechanisms including the link between vitamin D and inflammation, oxidative stress, and extracellular matrix accumulation. The present review aims to investigate the potential role of vitamin D in the development of diabetic kidney disease from a translational approach.

Effects of tumor necrosis factor-α inhibition on kidney fibrosis and inflammation in a mouse model of aristolochic acid nephropathy

Tumor necrosis factor (TNF)-α is a potent mediator of inflammation and is involved in the pathophysiology of chronic kidney disease (CKD). However, the effects of TNF-α inhibition on the progression of kidney fibrosis have not been fully elucidated. We examined the effects of TNF-α inhibition by etanercept (ETN) on kidney inflammation and fibrosis in mice with aristolochic acid (AA) nephropathy as a model of kidney fibrosis. C57BL/6 J mice were administered AA for 4 weeks, followed by a 4-week remodeling period. The mice exhibited kidney fibrosis, functional decline, and albuminuria concomitant with increases in renal mRNA expression of inflammation- and fibrosis-related genes. The 8-week ETN treatment partially but significantly attenuated kidney fibrosis and ameliorated albuminuria without affecting kidney function. These findings were accompanied by significant suppression of interleukin (IL)-1β, IL-6, and collagen types I and III mRNA expression. Moreover, ETN tended to reduce the AA-induced increase in interstitial TUNEL-positive cells with a significant reduction in Bax mRNA expression. Renal phosphorylated p38 MAPK was significantly upregulated by AA but was normalized by ETN. These findings indicate a substantial role for the TNF-α pathway in the pathogenesis of kidney fibrosis and suggest that TNF-α inhibition could become an adjunct therapeutic strategy for CKD with fibrosis.

Osteocrin ameliorates adriamycin nephropathy via p38 mitogen-activated protein kinase inhibition

Natriuretic peptides exert multiple effects by binding to natriuretic peptide receptors (NPRs). Osteocrin (OSTN) binds with high affinity to NPR-C, a clearance receptor for natriuretic peptides, and inhibits degradation of natriuretic peptides and consequently enhances guanylyl cyclase-A (GC-A/NPR1) signaling. However, the roles of OSTN in the kidney have not been well clarified. Adriamycin (ADR) nephropathy in wild-type mice showed albuminuria, glomerular basement membrane changes, increased podocyte injuries, infiltration of macrophages, and p38 mitogen-activated protein kinase (MAPK) activation. All these phenotypes were improved in OSTN- transgenic (Tg) mice and NPR3 knockout (KO) mice, with no further improvement in OSTN-Tg/NPR3 KO double mutant mice, indicating that OSTN works through NPR3. On the contrary, OSTN KO mice increased urinary albumin levels, and pharmacological blockade of p38 MAPK in OSTN KO mice ameliorated ADR nephropathy. In vitro, combination treatment with ANP and OSTN, or FR167653, p38 MAPK inhibitor, reduced Ccl2 and Des mRNA expression in murine podocytes (MPC5). OSTN increased intracellular cyclic guanosine monophosphate (cGMP) in MPC5 through GC-A. We have elucidated that circulating OSTN improves ADR nephropathy by enhancing GC-A signaling and consequently suppressing p38 MAPK activation. These results suggest that OSTN could be a promising therapeutic agent for podocyte injury.

Circular RNAs; powerful microRNA sponges to overcome diabetic nephropathy

Diabetic nephropathy (DN), also known as diabetic kidney disease (DKD), is a drastic renal complication of type 1 and type 2 diabetes mellitus (DM). Poorly controlled DM over the years, may disrupt kidneys' blood vessels, leading to the hypertension (HTN) and DN onset. During DN, kidneys' waste filtering ability becomes disturbed. Being on a healthy lifestyle and controlling both DM and HTN are now the best proceedings to prevent or at least delay DN occurrence. Unfortunately, about one-fourth of diabetic individuals eventually experience the corresponding renal failure, and thus it is critical to discover effective diagnostic biomarkers and therapeutic strategies to combat DN. In the past few years, circular RNAs (circRNAs), as covalently closed endogenous non-coding RNAs (ncRNAs), are believed to affect DN pathogenesis in a positive manner. CircRNAs are able to impact different cellular processes and signaling pathways by targeting biological molecules or various molecular mechanisms. Still, as a key regulatory axis, circRNAs can select miRNAs as their molecular targets, in which they are considered as miRNA sponges. In this way, circRNA-induced suppression of particular miRNAs may prevent from DN progression or promotes the DN elimination. Since the expression of circRNAs has also been reported to be increased in DN-associated cells and tissues, they can be employed as either diagnostic biomarkers or therapeutic targets.

Pharmacokinetics, Safety, and Tolerability of Selonsertib, an Apoptosis Signal-Regulating Kinase 1 (ASK1) Inhibitor, Following First-in-Human Single and Multiple Ascending Doses in Healthy Subjects

BACKGROUND

Selonsertib is a first-in-class inhibitor of apoptosis signal-regulating kinase 1 (ASK1) with therapeutic potential for fibrotic diseases. This phase I study evaluated the safety, tolerability, pharmacokinetics (PK), and food effect of selonsertib in healthy subjects.

METHODS

This was a double-blinded, randomized, placebo-controlled dose-escalation study. Healthy subjects received 1, 3, 10, 30, or 100 mg of selonsertib or placebo as single or multiple doses once daily for 14 days in the fasted state, or 30 mg or placebo single dose in the fed state. Blood and urine (single-dose cohorts only) samples for selonsertib PK were collected and safety was assessed throughout the study. Ex vivo pharmacodynamic (PD) assessment was performed in blood from a separate cohort of healthy donors using an auranofin-stimulated C-X-C motif chemokine ligand 1 (CXCL1) assay.

RESULTS

Overall, 107 subjects (83 active, 24 placebo) were enrolled and randomized to 11 cohorts. Selonsertib was generally well tolerated; adverse events were generally mild to moderate. Selonsertib was rapidly absorbed with dose-proportional PK of both parent and inactive metabolite GS-607509. There was no food effect on selonsertib PK. Renal excretion was a minor pathway of selonsertib elimination. Selonsertib half maximal effective concentration (EC₅₀) in human whole blood was determined to be 56 ng/mL.

CONCLUSIONS

Selonsertib exhibited a favorable PK profile amenable to once-daily dosing without regard to food. PD data suggest pharmacologically relevant exposures were achieved in the dose range evaluated. Study results support further clinical development of selonsertib.

Novel Anti-inflammatory and Anti-fibrotic Agents for Diabetic Kidney Disease-From Bench to Bedside

Chronic low-grade inflammation, now coined by the new paradigm as "metaflammation" or "metainflammation", has been linked to chronic kidney disease and its progression. In diabetes, altered metabolism denotes factors associated with the metabolic syndrome and hyperglycemia, among others. The interplay among hyperglycemia, oxidative stress, and inflammation in the pathogenesis of diabetic kidney disease (DKD) has been broadly explored. Identification of mediators of inflammatory processes involving macrophage infiltration, production of inflammasomes, release of cytokines, and activation of pertinent signaling pathways including mitogen-activated protein kinase, Jun N-terminal kinase, Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway (JAK/STAT), and apoptosis signal-regulating kinase 1 signaling mechanisms have enabled the development of therapeutic agents for DKD. This review describes the evidence supporting the contribution of the inflammatory response and fibrotic changes and focuses on selected, novel, promising drugs as well as repurposed drugs that have made it to phase 2, 3, or 4 of clinical trials in adults with type 2 diabetes mellitus and their potential to become an important part of our armamentarium to improve the management of DKD. Importantly, drugs that solely target inflammatory processes may be insufficient to fully optimize care of patients with DKD because of the complex nature of the disease.

A novel podocyte protein, R3h domain containing-like, inhibits TGF-β-induced p38 MAPK and regulates the structure of podocytes and glomerular basement membrane

Not only in kidney glomerular physiological function but also glomerular pathology especially in diabetic condition, glomerular podocytes play pivotal roles. Therefore, it is important to increase our knowledge about the genes and proteins expressed in podocytes. Recently, we have identified a novel podocyte-expressed gene, R3h domain containing-like (R3hdml) and analyzed its function in vivo as well as in vitro. Transforming growth factor-β (TGF-β) signaling regulated the expression of R3hdml. And R3hdml inhibited p38 mitogen-activated protein kinase phosphorylation, which was induced by TGF-β, leading to the amelioration of podocyte apoptosis. Furthermore, a lack of R3hdml in mice significantly worsened glomerular function in streptozotocin (STZ)-induced diabetes, while overexpression of R3hdml ameliorated albuminuria in STZ-induced diabetes. Our results surmise that the functional analyses of R3hdml may lead to the development of novel therapeutic strategies for diabetic nephropathy in the future. KEY MESSAGES: • A novel podocyte expressed protein R3h domain containing-like was identified. • R3HDML inhibits podocyte apoptosis by inhibiting TGF-β-mediated p38 MAPK signaling. • Overexpression of R3HDML ameliorates albuminuria in STZ-induced diabetes mice. • R3HDML may prove to be a novel therapeutic strategy for diabetic nephropathy.

Activation of GPR120 in podocytes ameliorates kidney fibrosis and inflammation in diabetic nephropathy

Diabetic nephropathy (DN) is one of the most common causes of end-stage renal disease worldwide. ω3-Fatty acids (ω3FAs) were found to attenuate kidney inflammation, glomerulosclerosis, and albuminuria in experimental and clinical studies of DN. As G protein-coupled receptor 120 (GPR120) was firstly identified as the receptor of ω3FAs, we here investigated the function of GPR120 in DN. We first examined the renal biopsies of DN patients, and found that GPR120 expression was negatively correlated with the progression of DN. Immunofluorescence staining analysis revealed that GPR120 protein was mainly located in the podocytes of the glomerulus. A potent and selective GPR120 agonist TUG-891 (35 mg · kg^-1 · d^-1, ig) was administered to db/db mice for 4 weeks. We showed that TUG-891 administration significantly improved urinary albumin excretion, protected against podocyte injury, and reduced collagen deposition in the glomerulus. In db/db mice, TUG-891 administration significantly inhibited the mRNA and protein expression of fibronectin, collagen IV, α-SMA, TGF-β1, and IL-6, and downregulated the phosphorylation of Smad3 and STAT3 to alleviate glomerulosclerosis. Similar results were observed in high-glucose-treated MPC5 podocytes in the presence of TUG-891 (10 μM). Furthermore, we showed that TUG-891 effectively upregulated GPR120 expression, and suppressed TAK1-binding protein-1 expression as well as the phosphorylation of TAK1, IKKβ, NF-κB p65, JNK, and p38 MAPK in db/db mice and high-glucose-treated MPC5 podocytes. Knockdown of GPR120 in MPC5 podocytes caused the opposite effects of TUG-891. In summary, our results highlight that activation of GPR120 in podocytes ameliorates renal inflammation and fibrosis to protect against DN.

Calcitriol attenuates renal tubular epithelial cells apoptosis via inhibiting p38MAPK signaling in diabetic nephropathy

AIMS

To observe the effect of calcitriol on tubular epithelial cells apoptosis in diabetic nephropathy (DN) and to explore the possible mechanism of its renal protection.

METHODS

In vivo, DN rats established by streptozocin (STZ) were treated with or without calcitriol by gavage. Rats were killed at 18 weeks after treatment. In vitro, HK-2 cells were cultured in high glucose with or without 1,25-dihydroxyvitamin D3. In some experiments, P38MAPK activator anisomycin was applied to incubate HK-2 cells. Cell apoptosis was detected by TUNEL or Annexin V-FITC/PI staining with flow cytometry. Immunohistochemical staining was used to observe the expression of VDR in kidney. Protein expression of cleaved caspase-3, Bax, Bcl-2, VDR, pp38MAPK and p38MAPK was assessed by western blotting.

RESULT

Calcitriol treatment ameliorated the severity of proteinuria and reduced renal tubular epithelial cells apoptosis in DN rats. In addition, calcitriol treatment significantly increased renal VDR expression and reduced the expression of p-p38MAPK in rats. In vitro, 1,25-dihydroxyvitamin D3 decreased the apoptotic rate of HK-2 cells induced by high glucose. In accord with the results from animal study, 1,25-dihydroxyvitamin D3 increased VDR expression, but decreased p-p38MAPK expression in HK-2 cells. Moreover, P38MAPK activator anisomycin blocked the anti-apoptotic effect of 1,25-dihydroxyvitamin D3 on HK-2 cells.

CONCLUSIONS

Calcitriol attenuates renal tubular cells apoptosis via VDR activation which inhibits p38MAPK signaling in DN rats.

Therapeutic application of nutraceuticals in diabetic nephropathy: Current evidence and future implications

Diabetes mellitus (DM) is a common metabolic disease which may cause several complications, such as diabetic nephropathy (DN). The routine medical treatments used for DM are not effective enough and have many undesirable side effects. Moreover, the global increased prevalence of DM makes researchers try to explore potential complementary or alternative treatments. Nutraceuticals, as natural products with pharmaceutical agents, have a wide range of therapeutic properties in various pathologic conditions such as DN. However, the exact underlying mechanisms have not been fully understood. The purpose of this review is to summarize recent findings on the effect of nutraceuticals on DN.

Pharmacological validation of targets regulating CD14 during macrophage differentiation

The signalling receptor for LPS, CD14, is a key marker of, and facilitator for, pro-inflammatory macrophage function. Pro-inflammatory macrophage differentiation remains a process facilitating a broad array of disease pathologies, and has recently emerged as a potential target against cytokine storm in COVID19. Here, we perform a whole-genome CRISPR screen to identify essential nodes regulating CD14 expression in myeloid cells, using the differentiation of THP-1 cells as a starting point. This strategy uncovers many known pathways required for CD14 expression and regulating macrophage differentiation while additionally providing a list of novel targets either promoting or limiting this process. To speed translation of these results, we have then taken the approach of independently validating hits from the screen using well-curated small molecules. In this manner, we identify pharmacologically tractable hits that can either increase CD14 expression on non-differentiated monocytes or prevent CD14 upregulation during macrophage differentiation. An inhibitor for one of these targets, MAP2K3, translates through to studies on primary human monocytes, where it prevents upregulation of CD14 following M-CSF induced differentiation, and pro-inflammatory cytokine production in response to LPS. Therefore, this screening cascade has rapidly identified pharmacologically tractable nodes regulating a critical disease-relevant process.

High sucrose diet induces morphological, structural and functional impairments in the renal tubules of Drosophila melanogaster: A model for studying type-2 diabetes mediated renal tubular dysfunction

Continuous feeding of high dietary sugar is strongly associated with type 2 diabetes (T2D) and its secondary complications. Diabetic nephropathy (DN) is a major secondary complication that leads to glomerular and renal tubular dysfunction. The present study is aimed to investigate the effects of chronic exposure of high sugar diet (HSD) on renal tubules. Malpighian tubules (MTs), a renal organ of Drosophila, were used as a model in the study. Feeding of HSD develops T2D condition in Drosophila. The MTs showed structural abnormalities in 20 days of HSD fed flies. Impaired insulin signaling, oxidative stress, enhanced levels of AGE-RAGE and induction of apoptosis were observed in the MTs of these flies. Further, altered expression of transporters, enhanced uric acid level and reduced fluid secretion rate confirmed the impaired function of MTs in these flies. RNA-seq and RT-PCR analyses in the MTs of HSD fed-and control-flies revealed the altered expression of candidate genes that regulate several important pathways including extracellular matrix (ECM), advanced glycation end products-receptor for advanced glycation end products (AGE-RAGE), transforming growth factor β (TGF-β), galactose, starch and sucrose metabolism that are well known mediators of renal tubular dysfunction in DN patients. Disruption of insulin signaling in the MTs also causes renal tubular dysfunction similar to HSD fed flies. Overall, the study suggests that phenotypes observed in the MTs of HSD fed flies recapitulate several hallmarks of renal tubular dysfunction in DN patients. Therefore, we conclude that MTs of HSD fed flies may be used for deciphering the underlying mechanisms of T2D mediated renal tubular dysfunction.

Ubiquitin-specific protease 19 blunts pathological cardiac hypertrophy via inhibition of the TAK1-dependent pathway

Ubiquitin‐specific protease 19 (USP19) belongs to USP family and is involved in promoting skeletal muscle atrophy. Although USP19 is expressed in the heart, the role of USP19 in the heart disease remains unknown. The present study provides in vivo and in vitro data to reveal the role of USP19 in preventing pathological cardiac hypertrophy. We generated USP19‐knockout mice and isolated neonatal rat cardiomyocytes (NRCMs) that overexpressed or were deficient in USP19 to investigate the effect of USP19 on transverse aortic constriction (TAC) or phenylephrine (PE)‐mediated cardiac hypertrophy. Echocardiography, pathological and molecular analysis were used to determine the extent of cardiac hypertrophy, fibrosis, dysfunction and inflammation. USP19 expression was markedly increased in rodent hypertrophic heart or cardiomyocytes underwent TAC or PE culturing, the increase was mediated by the reduction of Seven In Absentia Homolog‐2. The extent of TAC‐induced cardiac hypertrophy, fibrosis, dysfunction and inflammation in USP19‐knockout mice was exacerbated. Consistently, gain‐of‐function and loss‐of‐function approaches that involved USP19 in cardiomyocytes suggested that the down‐regulation of USP19 promoted the hypertrophic phenotype, while the up‐regulation of USP19 improved the worsened phenotype. Mechanistically, the USP19‐elicited cardiac hypertrophy improvement was attributed to the abrogation of the transforming growth factor beta‐activated kinase 1 (TAK1)‐p38/JNK1/2 transduction. Furthermore, the inhibition of TAK1 abolished the aggravated hypertrophy induced by the loss of USP19. In conclusion, the present study revealed that USP19 and the downstream of TAK1‐p38/JNK1/2 signalling pathway might be a potential target to attenuate pathological cardiac hypertrophy.

Association of Metformin Use with Asthma Exacerbation in Patients with Concurrent Asthma and Diabetes: A Systematic Review and Meta-Analysis of Observational Studies

Background

Asthma and diabetes are both diseases that affect a wide range of people worldwide. As a common treatment for diabetes, metformin has also been reported to be effective in improving asthma outcomes. We conducted a combined analysis to examine the efficacy of metformin in reducing asthma exacerbation in patients with concurrent asthma and diabetes.

Methods

We searched the PubMed, Embase, and CENTRAL databases for articles published prior to April 2020 to find observational studies of individuals with concurrent asthma and diabetes that compared the risk of asthma exacerbation between metformin users and nonusers. Two researchers separately screened the studies, extracted data, and evaluated the risk of bias. The primary outcome was the adjusted risk of asthma exacerbation. The secondary outcomes were the adjusted risk of asthma-related hospitalization and emergency room visits. Review Manager was used for data analysis and plotting. I² and χ² tests were used to estimate heterogeneity. A random effects or fixed effects model was used depending on the heterogeneity. Odds ratios were calculated for dichotomous variables.

Results

We included two studies with a total of 25252 patients. The pooled effect size showed that metformin was inversely associated with a risk of asthma exacerbation (OR = 0.65, 95% CI 0.28–1.48; χ² = 5.42, P=0.02; I² = 82%), asthma-related emergency department visits (OR = 0.81, 95% CI 0.74–0.89; χ² = 0.36, P=0.55; I² = 0%), and hospitalizations (OR = 0.43, 95% CI 0.14–1.29; χ² = 4.01, P=0.05; I² = 75%).

Conclusion

This meta-analysis suggested that metformin decreased the risk of asthma-related emergency room visits for patients with concurrent asthma and diabetes. Metformin reduced the risk of asthma-related hospitalization and exacerbation but was not statistically significant. More randomized trials involving larger samples should be considered, and the mechanisms of these effects need to be fully elucidated.

High Dietary Fat and Selenium Concentrations Exert Tissue- and Glutathione Peroxidase 1-Dependent Impacts on Lipid Metabolism of Young-Adult Mice

BACKGROUND

Excessive dietary selenium (Se; 3 mg/kg) or fat (>25%) intakes and overproduction of glutathione peroxidase 1 (GPX1) adversely affect body lipid metabolism.

OBJECTIVE

The objective was to reveal impacts and mechanisms of a moderately high Se and a high fat intake on lipid metabolism in Gpx1 knockout (KO) and wild-type (WT) mice.

METHODS

The KO and WT mice (males, 12-wk-old, body weight = 24.8 ± 0.703 g) were allotted to 4 groups each (n = 5) and fed a sucrose-torula yeast basal diet (5% corn oil) supplemented with 0.3 or 1.0 mg (+Se) Se/kg (as sodium selenite) and 0% or 25% [high-fat (HF)] lard for 6 wk. Multiple physiological and molecular biomarkers (68) related to lipid metabolism and selenogenome expression in plasma, liver, and/or adipose tissue were analyzed by 2-way (+Se by HF) ANOVA.

RESULTS

Compared with the control diet, the +Se diet decreased (P < 0.05) body-weight gain and plasma and liver concentrations of lipids (22-66%) but elevated (≤1.5-fold, P < 0.05) adipose tissue concentrations of lipids in the WT mice. The +Se diet up- and downregulated (P < 0.05) mRNA and/or protein concentrations of factors related to lipogenesis, selenogenome, and transcription, stress, and cell cycle in the liver (26% to 176-fold) and adipose tissues (14% to 1-fold), respectively, compared with the control diet in the WT mice. Many of these +Se diet effects were different (P < 0.05) from those of the HF diet and were eliminated or altered (P < 0.05) by the KO.

CONCLUSIONS

The +Se and HF diets exerted tissue-specific and GPX1 expression-dependent impacts on lipid metabolism and related gene expression in the young-adult mice. Our findings will help reveal metabolic potential and underlying mechanisms of supplementing moderately high Se to subjects with HF intakes.

Assessing the Impact of Losmapimod on Proteinuria in Idiopathic Focal Segmental Glomerulosclerosis

Introduction

Idiopathic focal segmental glomerulosclerosis (FSGS) is a leading cause of nephrotic syndrome and end-stage renal disease. In preclinical models and biopsies of human FSGS kidneys, p38 mitogen-activated protein kinase (MAPK) has demonstrated enhanced activity; and p38 MAPK inhibition has improved disease markers. This proof-of-concept trial aimed to assess efficacy, safety, tolerability, and pharmacokinetics of losmapimod, an oral p38 MAPK inhibitor, in humans with FSGS.

Methods

A single-arm, multicenter, open-label, Phase II trial (NCT02000440) was conducted in adults with FSGS; proteinuria ≥2.0 g/d; estimated glomerular filtration rate (eGFR) ≥45 ml/min per 1.73 m²; blood pressure <140/90 mm Hg. Collapsing and genetic forms of FSGS were excluded. The primary endpoint was number of patients with ≥50% proteinuria reduction and eGFR ≥70% of baseline after receiving losmapimod twice-daily for 16 to 24 weeks.

Results

Seventeen patients received ≥1 losmapimod dose. No patients achieved the primary endpoint; therefore, the study was terminated following a prespecified interim analysis. At week 24, proteinuria reductions between 20% and <50% were observed in 4 patients and proteinuria increases >20% in 3 patients. One patient achieved a proteinuria response (≥50% reduction) at week 2 but subsequently relapsed. Losmapimod pharmacokinetics were consistent with prior studies. No serious adverse events (AEs) were reported.

Conclusion

p38 MAPK inhibition with losmapimod did not result in ≥50% reduction of proteinuria in patients with FSGS. However, study population heterogeneity may have contributed to our negative findings and therefore this does not eliminate the potential to demonstrate benefit in a population more sensitive to p38 MAPK inhibition if identifiable in the future by precision-medicine methods.

Circ_0000285 promotes podocyte injury through sponging miR-654-3p and activating MAPK6 in diabetic nephropathy

Recently, increasing evidence has reported that circRNAs are non-coding RNAs and they bind with the corresponding miRNAs to modulate the target genes. However, the detailed role of circRNAs in the pathogenesis of DN still remains poorly known. Currently, we aimed to study how circ_0000285 functions in DN development. We found that circ_0000285 was significantly increased in DN mice models and mouse podocytes incubated with HG. Then, circ_0000285 was overexpressed in mouse podocytes and we observed that overexpression of circ_0000285 promoted podocytes injury. Moreover, miR-654-3p was precited as a target of circ_0000285. It was shown that circ_0000285 was strongly pulled down by circ_0000285 specific probe and circ_0000285 specific probe was used to successfully enrich miR-654-3p. In addition, we reported that miR-654-3p was obviously down-regulated in DN. Inhibitors of miR-654-3p greatly reversed the effects of circ_0000285 siRNA on podocytes injury. Moreover, the inflammation release was restrained by loss of circ_0000285, while induced by miR-654-3p inhibitors. IL-6, L-1β and TNF-α level was remarkably depressed by the knockdown of circ_0000285 and miR-654-3p inhibitors induced that. Furthermore, MAPK6 was confirmed as a direct downstream target of miR-654-3p. As shown, MAPK6 was markedly suppressed by circ_0000285 siRNA, which was rescued by the decrease of miR-654-3p. These findings revealed that circ_0000285 promoted podocyte injury via sponging miR-654-3p and activating MAPK6 in DN.

Discovery of a 2-pyridinyl urea-containing compound YD57 as a potent inhibitor of apoptosis signal-regulating kinase 1 (ASK1)

Inhibition of MAP3K kinase ASK1 has been an attractive strategy for the treatment of nonalcoholic steatohepatitis and multiple sclerosis, among others. Herein, we reported the discovery of 2-pyridinyl urea-containing compound 14l (YD57) as a potent, small-molecule inhibitor of ASK1. 14l was selective against MAP3K kinases ASK2 and TAK1 (>140-fold), while it also inhibited several cell cycle regulating kinases with IC₅₀ values in a range of 90-400 nM (<20-fold selectivity). As a consequence, 14l had stronger apoptosis induction, more potent G1 cell cycle arrest activities, and lower IC₅₀ value of cell growth inhibition than that of GS4997 in HepG2 cancer cell line. On the other hand, 14l did not inhibit ASK1 and p38 phosphorylation in intact cells. We reason that the multi-target effects of 14l likely neutralized the activities caused by inhibition of cellular ASK1. Future studies of these ASK1 inhibitors should pay close attention to their kinome selectivity profile.

Effects of Selonsertib in Patients with Diabetic Kidney Disease

BACKGROUND

Apoptosis signal-regulating kinase 1 (ASK1) activation in glomerular and tubular cells resulting from oxidative stress may drive kidney disease progression. Findings in animal models identified selonsertib, a selective ASK1 inhibitor, as a potential therapeutic agent.

METHODS

In a phase 2 trial evaluating selonsertib's safety and efficacy in adults with type 2 diabetes and treatment-refractory moderate-to-advanced diabetic kidney disease, we randomly assigned 333 adults in a 1:1:1:1 allocation to selonsertib (oral daily doses of 2, 6, or 18 mg) or placebo. Primary outcome was change from baseline eGFR at 48 weeks.

RESULTS

Selonsertib appeared safe, with no dose-dependent adverse effects over 48 weeks. Although mean eGFR for selonsertib and placebo groups did not differ significantly at 48 weeks, acute effects related to inhibition of creatinine secretion by selonsertib confounded eGFR differences at 48 weeks. Because of this unanticipated effect, we used piecewise linear regression, finding two dose-dependent effects: an acute and more pronounced eGFR decline from 0 to 4 weeks (creatinine secretion effect) and an attenuated eGFR decline between 4 and 48 weeks (therapeutic effect) with higher doses of selonsertib. A post hoc analysis (excluding data for 20 patients from two sites with Good Clinical Practice compliance-related issues) found that between 4 and 48 weeks, rate of eGFR decline was reduced 71% for the 18-mg group relative to placebo (difference 3.11±1.53 ml/min per 1.73 m² annualized over 1 year; 95% confidence interval, 0.10-6.13; nominal P=0.043). Effects on urine albumin-to-creatinine ratio did not differ between selonsertib and placebo.

CONCLUSIONS

Although the trial did not meet its primary endpoint, exploratory post hoc analyses suggest that selonsertib may slow diabetic kidney disease progression.

The circulating exosomal microRNAs related to albuminuria in patients with diabetic nephropathy

BACKGROUND

Diabetic nephropathy (DN) is associated with high risk of cardiovascular disease and mortality. Exosomal microRNAs (miRNAs) regulate gene expression in a variety of tissues and play important roles in the pathology of various diseases. We hypothesized that the exosomal miRNA profile would differ between DN patients and patients without nephropathy.

METHODS

We prospectively enrolled 74 participants, including healthy volunteers (HVs), diabetic patients without nephropathy, and those with DN. The serum exosomal miRNA profiles of participants were examined using RNA sequencing.

RESULTS

The expression levels of 107 miRNAs differed between HVs and patients without DN, whereas the expression levels of 95 miRNAs differed between HVs and patients with DN. Among these miRNAs, we found 7 miRNAs (miR-1246, miR-642a-3p, let-7c-5p, miR-1255b-5p, let-7i-3p, miR-5010-5p, miR-150-3p) that were uniquely up-regulated in DN patients compared to HVs, and miR-4449 that was highly expressed in DN patients compared to patients without DN. A pathway analysis revealed that these eight miRNAs are likely involved in MAPK signaling, integrin function in angiogenesis, and regulation of the AP-1 transcription factor. Moreover, they were all significantly correlated with the degree of albuminuria.

CONCLUSIONS

Patients with DN have a different serum exosomal miRNA profile compared to HVs. These miRNAs may be promising candidates for the diagnosis and treatment of DN and cardiovascular disease.

DUSP26 regulates podocyte oxidative stress and fibrosis in a mouse model with diabetic nephropathy through the mediation of ROS

Diabetic nephropathy (DN) is a leading cause of renal failure worldwide. Unfortunately, the pathogenetic mechanism of DN is far from to be understood. Dual-specificity phosphatase 26 (DUSP26) is a member of the Dusp protein family, and is suggested to be involved in divers biological and pathological processes, such as cell growth, differentiation, inflammation and apoptosis. However, its role in the development of DN is still vague. In this study, we found that DUSP26 expression was increased in kidney of DN patients. Then, the wild type (DUSP26^+/+) and gene knockout (DUSP26^-/-) mice were used to further explore the effects of DUSP26 on DN development induced by streptozotocin (STZ). DUSP26 deficiency accelerated renal injury and dysfunction, as evidenced by the elevated glomerulosclerosis, reduced expression of Nephrin and promoted glomerular basement membrane thickness. In addition, STZ treatment resulted in reactive oxygen species (ROS) accumulation, H₂O₂ overproduction and superoxide dismutase (SOD) reduction in renal cortex or glomeruli of mice. The ROS production caused the activation of mitogen-activated protein kinase (MAPKs) signaling in kidney glomeruli of STZ-induced mice. These in vivo pathological processes were further confirmed in the differentiated podocytes stimulated by glucose (GLU). Intriguingly, we found that STZ-induced DN as mentioned above was further accelerated by DUSP26^-/- in mice following STZ injection. Moreover, STZ-induced fibrosis in kidney glomeruli of DN mice was markedly prolonged in DUSP26-knockout mice through potentiating transforming growth factor-β1 (TGF-β1) expression. More importantly, reducing ROS generation could significantly abolish DUSP26 knockdown-exacerbated TGF-β1 expression and MAPKs activation, thereby protecting podocytes from GLU-induced podocyte injury. Thus, DUSP26-regulated DN development was largely dependent on ROS generation. Taken together, we concluded that DUSP26 might be a promising therapeutic target for developing effective treatments against DN progression.

Cellular senescence: Molecular mechanisms and pathogenicity

Cellular senescence is the arrest of normal cell division. Oncogenic genes and oxidative stress, which cause genomic DNA damage and generation of reactive oxygen species, lead to cellular senescence. The senescence-associated secretory phenotype is a distinct feature of senescence. Senescence is normally involved in the embryonic development. Senescent cells can communicate with immune cells to invoke an immune response. Senescence emerges during the aging process in several tissues and organs. In fact, increasing evidence shows that cellular senescence is implicated in aging-related diseases, such as nonalcoholic fatty liver disease, obesity and diabetes, pulmonary hypertension, and tumorigenesis. Cellular senescence can also be induced by microbial infection. During cellular senescence, several signaling pathways, including those of p53, nuclear factor-κB (NF-κB), mammalian target of rapamycin, and transforming growth factor-beta, play important roles. Accumulation of senescent cells can trigger chronic inflammation, which may contribute to the pathological changes in the elderly. Given the variety of deleterious effects caused by cellular senescence in humans, strategies have been proposed to control senescence. In this review, we will focus on recent studies to provide a brief introduction to cellular senescence, including associated signaling pathways and pathology.

ASK1 contributes to fibrosis and dysfunction in models of kidney disease

Oxidative stress is an underlying component of acute and chronic kidney disease. Apoptosis signal-regulating kinase 1 (ASK1) is a widely expressed redox-sensitive serine threonine kinase that activates p38 and c-Jun N-terminal kinase (JNK) mitogen-activated protein kinase kinases, and induces apoptotic, inflammatory, and fibrotic signaling in settings of oxidative stress. We describe the discovery and characterization of a potent and selective small-molecule inhibitor of ASK1, GS-444217, and demonstrate the therapeutic potential of ASK1 inhibition to reduce kidney injury and fibrosis. Activation of the ASK1 pathway in glomerular and tubular compartments was confirmed in renal biopsies from patients with diabetic kidney disease (DKD) and was decreased by GS-444217 in several rodent models of kidney injury and fibrosis that collectively represented the hallmarks of DKD pathology. Treatment with GS-444217 reduced progressive inflammation and fibrosis in the kidney and halted glomerular filtration rate decline. Combination of GS-444217 with enalapril, an angiotensin-converting enzyme inhibitor, led to a greater reduction in proteinuria and regression of glomerulosclerosis. These results identify ASK1 as an important target for renal disease and support the clinical development of an ASK1 inhibitor for the treatment of DKD.

A Novel Regulator of Type II Diabetes: MicroRNA-143

MiR-143 is an miRNA with the function of specifically inhibiting the insulin-AKT pathway via the downregulation of oxysterol-binding protein-related protein 8 (ORP8), thus resulting in the inhibition of AKT phosphorylation, insulin tolerance, and final development of type II diabetes mellitus (T2DM). Aerobic exercise can prevent T2DM by downregulating miR-143. However, the underlying mechanisms for exercise-induced change of miR-143 remain unclear. In the present study, we will summarize the involvement of miR-143 in regulating the development of T2DM and the underlying mechanisms for potential diagnosis, prevention, and treatments, including exercise intervention for T2DM by targeting miR-143.

Esculin ameliorates cognitive impairment in experimental diabetic nephropathy and induces anti-oxidative stress and anti-inflammatory effects via the MAPK pathway

Esculin is a derivative of coumarin, which is also an active ingredient of ash bark, and has antibacterial, anti-inflammatory, anti‑allergy and skin protective effects. The underlying mechanism and protective effects of esculin on cognitive impairment in experimental diabetic nephropathy (DN) was investigated in the present study. Male C57BL/6J 6‑week‑old mice were injected intravenously with a single dose of streptozotocin (STZ; 30 mg/kg). At 2 weeks after the STZ injection, mice received intravenous injection with 5, 10 or 20 mg/kg esculin for 2 weeks. In the present study, the results of the Morris water maze test demonstrated that esculin significantly improved behavior and recognition memory in STZ‑induced diabetic rats. Furthermore, treatment of STZ‑induced diabetic rats with esculin significantly inhibited tumor necrosis factor‑α, interleukin‑6, malondialdehyde, monocyte chemoattractant protein‑1 and intracellular adhesion molecule‑1 activity levels, and increased the activity of superoxide dismutase, in the kidney, which was determined by ELISA. In addition, esculin treatment significantly suppressed the renal protein expression of activator protein 1, phosphorylated (p)‑p38 mitogen activated protein kinase (MAPK) and p‑c‑Jun N‑terminal kinase, and increased p‑extracellular signal regulated kinase 1/2 protein expression, in STZ‑induced diabetic rats, as determined by western blotting. These results indicate that esculin may ameliorate cognitive impairment in experimental DN, and exert anti‑oxidative stress and anti‑inflammatory effects, via the MAPK signaling pathway. Thus, it may serve as a potential target for cognitive impairment of DN in the future.

Immunologic and endocrine functions of adipose tissue: implications for kidney disease

Excess adiposity can induce adverse sequelae in multiple cell types and organ systems. The transition from the lean to the obese state is characterized by fundamental cellular changes at the level of the adipocyte. These changes affect the local microenvironment within the respective adipose tissue but can also affect nonadipose systems. Adipocytes within fat pads respond to chronic nutrient excess through hyperplasia or hypertrophy, which can differentially affect interorgan crosstalk between various adipose depots and other organs. This crosstalk is dependent on the unique ability of the adipocyte to coordinate metabolic adjustments throughout the body and to integrate responses to maintain metabolic homeostasis. These actions occur through the release of free fatty acids and metabolites during times of energy need - a process that is altered in the obese state. In addition, adipocytes release a wide array of signalling molecules, such as sphingolipids, as well as inflammatory and hormonal factors (adipokines) that are critical for interorgan crosstalk. The interactions of adipose tissue with the kidney - referred to as the adipo-renal axis - are important for normal kidney function as well as the response of the kidney to injury. Here, we discuss the mechanistic basis of this interorgan crosstalk, which clearly has great therapeutic potential given the increasing rates of chronic kidney disease secondary to obesity and type 2 diabetes mellitus.

β-arrestin-2 is involved in irisin induced glucose metabolism in type 2 diabetes via p38 MAPK signaling

Type 2 diabetes mellitus (T2DM) is a common metabolic disease worldwide. It has been reported that irisin play regulatory role in glucose metabolism in T2DM. However, the underlying mechanism involved in that is not completely known. Herein, we determined the novel role of β-arrestin-2 in irisin-induced glucose utilization in diabetes. Effects of irisin and β-arrestin-2 on glucose utilization were investigated in a rat model of diabetes and in diabetic C2C12 cells in vitro. Results showed that irisin had positive role in glucose metabolism via regulating glucose tolerance as well as uptake in cardiac and skeletal muscle tissues, as evidenced by IPGTT, 2-deoxyglucose uptake and plasma membrane GLUT-4 assay. β-arrestin-2 also improved glucose utilization in diabetes by increasing the glucose uptake and insulin sensitivity, as shown in mice overexpressing β-arrestin-2. In diabetic C2C12 myocytes, irisin-induced GLUT4 and glucose uptake were restrained by β-arrestin-2 inhibition, but was enhanced by β-arrestin-2 overexpression. Additionally, irisin and β-arrestin-2 increased the activation of p38 MAPK in diabetic C2C12 cells, and the repression of p38 MAPK activation decreased the glucose uptake and plasma membrane GLUT-4 was enhanced by irisin and β-arrestin-2 overexpression in diabetic C2C12 cells. In conclusion, we demonstrated that β-arrestin-2 has a crucial role in irisin induced glucose metabolism in T2DM by regulating the p38 MAPK signaling. This might present a novel therapeutic target of treatment for human diabetes.