PTEN-induced partial epithelial-mesenchymal transition drives diabetic kidney disease

Post-translational modifications in kidney diseases and associated cardiovascular risk

Patients with chronic kidney disease (CKD) are at an increased cardiovascular risk compared with the general population, which is driven, at least in part, by mechanisms that are uniquely associated with kidney disease. In CKD, increased levels of oxidative stress and uraemic retention solutes, including urea and advanced glycation end products, enhance non-enzymatic post-translational modification events, such as protein oxidation, glycation, carbamylation and guanidinylation. Alterations in enzymatic post-translational modifications such as glycosylation, ubiquitination, acetylation and methylation are also detected in CKD. Post-translational modifications can alter the structure and function of proteins and lipoprotein particles, thereby affecting cellular processes. In CKD, evidence suggests that post-translationally modified proteins can contribute to inflammation, oxidative stress and fibrosis, and induce vascular damage or prothrombotic effects, which might contribute to CKD progression and/or increase cardiovascular risk in patients with CKD. Consequently, post-translational protein modifications prevalent in CKD might be useful as diagnostic biomarkers and indicators of disease activity that could be used to guide and evaluate therapeutic interventions, in addition to providing potential novel therapeutic targets.

Dysregulated Urinary Extracellular Vesicle Small RNAs in Diabetic Nephropathy: Implications for Diagnosis and Therapy

Background

Diabetic nephropathy (DN) represents a major chronic kidney disorder and a leading cause of end-stage renal disease (ESRD). Small RNAs have been showing great promise as diagnostic markers as well as drug targets. Identifying dysregulated micro RNAs (miRNAs) could help in identifying disease biomarkers and investigation of downstream interactions, shedding light on the molecular pathophysiology of DN. In this study, we analyzed small RNAs within human urinary extracellular vesicles (ECVs) from DN patients using small RNA next-generation sequencing.

Method

In this cross-sectional study, urine samples were collected from 88 participants who were divided into 3 groups: type 2 diabetes (T2D) with DN (T2D + DN, n = 20), T2D without DN (T2D - DN, n = 40), and healthy individuals (n = 28). The study focused on isolating urinary ECVs to extract and sequence small RNAs. Differentially expressed small RNAs were identified, and a functional enrichment analysis was conducted.

Results

The study revealed a distinct subset of 13 miRNAs and 10 Piwi-interacting RNAs that were significantly dysregulated in urinary ECVs of the DN group when compared to other groups. Notably, miR-151a-3p and miR-182-5p exhibited a unique expression pattern, being downregulated in the T2D - DN group, and upregulated in the T2D + DN group, thus demonstrating their effectiveness in distinguishing patients between the 2 groups. Eight driver genes were identified PTEN, SMAD2, SMAD4, VEGFA, CCND2, CDK6, LIN28B, and CHD1.

Conclusion

Our findings contribute valuable insights into the pathogenesis of DN, uncovering novel biomarkers and identifying potential therapeutic targets that may aid in managing and potentially decelerating the progression of the disease.

Lactate drives epithelial-mesenchymal transition in diabetic kidney disease via the H3K14la/KLF5 pathway

High levels of urinary lactate are an increased risk of progression in patients with diabetic kidney disease (DKD). However, it is still unveiled how lactate drive DKD. Epithelial-mesenchymal transition (EMT), which is characterized by the loss of epithelial cells polarity and cell-cell adhesion, and the acquisition of mesenchymal-like phenotypes, is widely recognized a critical contributor to DKD. Here, we found a switch from oxidative phosphorylation (OXPHOS) toward glycolysis in AGEs-induced renal tubular epithelial cells, thus leading to elevated levels of renal lactic acid. We demonstrated that reducing the lactate levels markedly delayed EMT progression and improved renal tubular fibrosis in DKD. Mechanically, we observed lactate increased the levels of histone H3 lysine 14 lactylation (H3K14la) in DKD. ChIP-seq & RNA-seq results showed histone lactylation contributed to EMT process by facilitating KLF5 expression. Moreover, KLF5 recognized the promotor of cdh1 and inhibited its transcription, which accelerated EMT of DKD. Additionally, nephro-specific knockdown and pharmacological inhibition of KLF5 diminished EMT development and attenuated DKD fibrosis. Thus, our study provides better understanding of epigenetic regulation of DKD pathogenesis, and new therapeutic strategy for DKD by disruption of the lactate-drived H3K14la/KLF5 pathway.

Regulation of YAP translocation by myeloid Pten deficiency alleviates acute lung injury via inhibition of oxidative stress and inflammation

BACKGROUND

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is intricately involved in modulating the inflammatory response in acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Nevertheless, the myeloid PTEN governing Hippo-YAP pathway mediated oxidative stress and inflammation in lipopolysaccharide (LPS)-induced ALI remains to be elucidate.

METHODS

The floxed Pten (PtenFL/FL) and myeloid-specific Pten knockout (PtenM-KO) mice were intratracheal instill LPS (5 mg/kg) to establish ALI, then Yap siRNA mix with the mannose-conjugated polymers was used to knockdown endogenous macrophage YAP in some PtenM-KO mice before LPS challenged. The bone marrow-derived macrophages (BMMs) from PtenFL/FL and PtenM-KO mice were obtained, and BMMs were transfected with CRISPR/Cas9-mediated glycogen synthase kinase 3 Beta (GSK3β) knockout (KO) or Yes-associated protein (YAP) KO vector subjected to LPS (100 ng/ml) challenged or then cocultured with MLE12 cells.

RESULTS

Here, our findings demonstrate that myeloid-specific PTEN deficiency exerts a protective against LPS-induced oxidative stress and inflammation dysregulated in ALI model. Moreover, ablation of the PTEN-YAP axis in macrophages results in reduced nuclear factor-E2-related factor-2 (NRF2) expression, a decrease in antioxidant gene expression, augmented levels of free radicals, lipid and protein peroxidation, heightened generation of pro-inflammatory cytokines, ultimately leading to increased apoptosis in MLE12 cells. Mechanistically, it is noteworthy that the deletion of myeloid PTEN promotes YAP translocation and regulates NRF2 expression, alleviating LPS-induced ALI via the inhibition of GSK3β and MST1 binding.

CONCLUSIONS

Our study underscores the crucial role of the myeloid PTEN-YAP-NRF2 axis in governing oxidative stress and inflammation dysregulated in ALI, indicating its potential as a therapeutic target for ALI.

Research progress on Alpinia oxyphylla in the treatment of diabetic nephropathy

Diabetic nephropathy (DN) constitutes a major microvascular complication of diabetes and is a primary cause of mortality in diabetic individuals. With the global rise in diabetes, DN has become an urgent health issue. Currently, there is no definitive cure for DN. Alpinia oxyphylla, a Chinese herbal medicine traditionally used, exhibits a wide range of pharmacological effects and is frequently used in the prevention and management of DN. This paper offers an extensive review of the biological mechanisms by which A. oxyphylla delivers therapeutic advantages in DN management. These mechanisms include activating podocyte autophagy, regulating non-coding RNA, modulating gut microbiota, alleviating lipotoxicity, counteracting oxidative stress, and diminishing inflammatory responses, underscoring the therapeutic potential of A. oxyphylla in DN treatment.

Scopoletin alleviates high glucose-induced toxicity in human renal proximal tubular cells via inhibition of oxidative damage, epithelial-mesenchymal transition, and fibrogenesis

BACKGROUND

Recent years of evidence suggest the crucial role of renal tubular cells in developing diabetic kidney disease. Scopoletin (SCOP) is a plant-based coumarin with numerous biological activities. This study aimed to determine the effect of SCOP on renal tubular cells in developing diabetic kidney disease and to elucidate mechanisms.

METHODS AND RESULTS

In this study, SCOP was evaluated in vitro using renal proximal tubular (HK-2) cells under hyperglycemic conditions to understand its mechanism of action. In HK-2 cells, SCOP alleviated the high glucose-generated reactive oxygen species (ROS), restored the levels of reduced glutathione, and decreased lipid peroxidation. High glucose-induced alteration in the mitochondrial membrane potential was markedly restored in the SCOP-treated cells. Moreover, SCOP significantly reduced the high glucose-induced apoptotic cell population in the Annexin V-FITC flow cytometry study. Furthermore, high glucose markedly elevated the mRNA expression of fibrotic and extracellular matrix (ECM) components, namely, transforming growth factor (TGF)-β, alfa-smooth muscle actin (α-SMA), collagen I, and collagen III, in HK-2 cells compared to the untreated cells. SCOP treatment reduced these mRNA expressions compared to the high glucose-treated cells. Collagen I and TGF-β protein levels were also significantly reduced in the SCOP-treated cells. Further findings in HK-2 cells revealed that SCOP interfered with the epithelial-mesenchymal transition (EMT) in the high glucose-treated HK-2 cells by normalizing E-cadherin and downregulating the vimentin and α-SMA proteins.

CONCLUSIONS

In conclusion, SCOP modulates the high glucose-generated renal tubular cell oxidative damage and accumulation of ECM components and may be a promising molecule against diabetic nephropathy.

Qufeng tongluo decoction decreased proteinuria in diabetic mice by protecting podocytes via promoting autophagy

Background

Diabetic kidney disease (DKD) is one of diabetic complications, which has become the leading cause of end-stage kidney disease. In addition to angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker(ACEI/ARB) and sodium-glucose cotransporter-2 inhibitor (SGLT2i), traditional Chinese medicine (TCM) is an effective alternative treatment for DKD. In this study, the effect of Qufeng Tongluo (QFTL) decoction in decreasing proteinuria has been observed and its mechanism has been explored based on autophagy regulation in podocyte.

Methods

In vivo study, db/db mice were used as diabetes model and db/m mice as blank control. Db/db mice were treated with QFTL decoction, rapamycin, QFTL + 3-Methyladenine (3-MA), trehalose, chloroquine (CQ) and QFTL + CQ. Mice urinary albumin/creatinine (UACR), nephrin and autophagy related proteins (LC3 and p62) in kidney tissue were detected after intervention of 9 weeks. Transcriptomics was operated with the kidney tissue from model group and QFTL group. In vitro study, mouse podocyte clone-5 (MPC-5) cells were stimulated with hyperglycemic media (30 mmol/L glucose) or cultured with normal media. High-glucose-stimulated MPC-5 cells were treated with QFTL freeze-drying powder, rapamycin, CQ, trehalose, QFTL+3-MA and QFTL + CQ. Cytoskeletal actin, nephrin, ATG-5, ATG-7, Beclin-1, cathepsin L and cathepsin B were assessed. mRFP-GFP-LC3 was established by stubRFP-sensGFP-LC3 lentivirus transfection.

Results

QFTL decoction decreased the UACR and increased the nephrin level in kidney tissue and high-glucose-stimulated podocytes. Autophagy inhibitors, including 3-MA and chloroquine blocked the effects of QFTL decoction. Further study showed that QFTL decoction increased the LC3 expression and relieved p62 accumulation in podocytes of db/db mice. In high-glucose-stimulated MPC-5 cells, QFTL decoction rescued the inhibited LC3 and promoted the expression of ATG-5, ATG-7, and Beclin-1, while had no effect on the activity of cathepsin L and cathepsin B. Results of transcriptomics also showed that 51 autophagy related genes were regulated by QFTL decoction, including the genes of ATG10, SCOC, ATG4C, AMPK catalytic subunit, PI3K catalytic subunit, ATG3 and DRAM2.

Conclusion

QFTL decoction decreased proteinuria and protected podocytes in db/db mice by regulating autophagy.

Human umbilical cord mesenchymal stem cell-derived exosomes ameliorate renal fibrosis in diabetic nephropathy by targeting Hedgehog/SMO signaling

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease globally. Currently, there are no effective drugs for the treatment of DN. Although several studies have reported the therapeutic potential of mesenchymal stem cells, the underlying mechanisms remain largely unknown. Here, we report that both human umbilical cord MSCs (UC-MSCs) and UC-MSC-derived exosomes (UC-MSC-exo) attenuate kidney damage, and inhibit epithelial-mesenchymal transition (EMT) and renal fibrosis in streptozotocin-induced DN rats. Strikingly, the Hedgehog receptor, smoothened (SMO), was significantly upregulated in the kidney tissues of DN patients and rats, and positively correlated with EMT and renal fibrosis. UC-MSC and UC-MSC-exo treatment resulted in decrease of SMO expression. In vitro co-culture experiments revealed that UC-MSC-exo reduced EMT of tubular epithelial cells through inhibiting Hedgehog/SMO pathway. Collectively, UC-MSCs inhibit EMT and renal fibrosis by delivering exosomes and targeting Hedgehog/SMO signaling, suggesting that UC-MSCs and their exosomes are novel anti-fibrotic therapeutics for treating DN.

N6-methyladenosine RNA methylation in diabetic kidney disease

Diabetic kidney disease (DKD) is a major microvascular complication of diabetes, and hyperglycemic memory associated with diabetes carries the risk of disease occurrence, even after the termination of blood glucose injury. The existence of hyperglycemic memory supports the concept of an epigenetic mechanism involving n6-methyladenosine (m6A) modification. Several studies have shown that m6A plays a key role in the pathogenesis of DKD. This review addresses the role and mechanism of m6A RNA modification in the progression of DKD, including the regulatory role of m6A modification in pathological processes, such as inflammation, oxidative stress, fibrosis, and non-coding (nc) RNA. This reveals the importance of m6A in the occurrence and development of DKD, suggesting that m6A may play a role in hyperglycemic memory phenomenon. This review also discusses how some gray areas, such as m6A modified multiple enzymes, interact to affect the development of DKD and provides countermeasures. In conclusion, this review enhances our understanding of DKD from the perspective of m6A modifications and provides new targets for future therapeutic strategies. In addition, the insights discussed here support the existence of hyperglycemic memory effects in DKD, which may have far-reaching implications for the development of novel treatments. We hypothesize that m6A RNA modification, as a key factor regulating the development of DKD, provides a new perspective for the in-depth exploration of DKD and provides a novel option for the clinical management of patients with DKD.

Imperatorin ameliorates kidney injury in diabetic mice by regulating the TGF-β/Smad2/3 signaling axis, epithelial-to-mesenchymal transition, and renal inflammation

Diabetic nephropathy (DN) is a serious concern in patients with diabetes mellitus. Prolonged hyperglycemia induces oxidative damage, chronic inflammation, and build-up of extracellular matrix (ECM) components in the renal cells, leading to kidney structural and functional changes. Imperatorin (IMP) is a naturally occurring furanocoumarin derivative with proven antioxidative and anti-inflammatory properties. We investigated whether IMP could improve DN and employed high glucose (HG)-induced HK-2 cells and high-fat diet-fed streptozotocin (HFD/STZ)-generated DN experimental model in C57BL/6 mice. In vitro, IMP effectively reduced the HG-activated reactive oxygen species generation, disturbance in the mitochondrial membrane potential (MMP) and epithelial-to-mesenchymal transition (EMT)-related markers, and the transforming growth factor (TGF)-β and collagen 1 expression in HK-2 cells. In vivo, we found an elevation of serum creatinine, kidney histology alterations, and collagen build-up in the kidneys of the DN control group. Also, we found an altered expression of EMT-related markers, upregulation of the TGF-β/Smad2/3 axis, and elevated pro-inflammatory molecules, TNF-α, IL-1β, IL-18 and phospho-NF-kB (p65) in the DN control group. IMP treatment did not significantly reduce the blood glucose level compared to the DN control group. However, IMP treatment effectively improved renal damage by ameliorating kidney histological changes and serum renal injury markers. IMP treatment restored renal antioxidants and exhibited anti-inflammatory effects in the kidneys. Moreover, the abnormal manifestation of EMT-related attributes and elevated levels of TGF-β, phospho-Smad2/3, and collagen 1 were also normalized in the IMP treatment group. Our findings highlight that IMP may be a potential candidate for treating DN.

Hippo/YAP signaling pathway: a new therapeutic target for diabetes mellitus and vascular complications

Diabetic angiopathy, which includes diabetic kidney disease (DKD), cardio-cerebrovascular disease, and diabetic retinopathy (DR) among other diseases, is one of the most common complications affecting diabetic patients. Among these, DKD, which is a major cause of morbidity and mortality, affects about 40% of diabetic patients. Similarly, DR involves retinal neovascularization and neurodegeneration as a result of chronic hyperglycemia and is the main cause of visual impairment and blindness. In addition, inflammation also promotes atherosclerosis and diabetes, with atherosclerosis-related cardiovascular diseases being often a main cause of disability or death in diabetic patients. Given that vascular diseases caused by diabetes negatively impact human health, it is therefore important to identify appropriate treatments. In this context, some studies have found that the Hippo/Yes-associated protein (YAP) pathway is a highly evolutionarily conserved protein kinase signal pathway that regulates organ growth and size through its effector signaling pathway Transcriptional co-Activator with PDZ-binding motif (TAZ) and its YAP. YAP is a key factor in the Hippo pathway. The activation of YAP regulates gluconeogenesis, thereby regulating glucose tolerance levels; silencing the YAP gene thereby prevents the formation of glomerular fibrosis. YAP can combine with TEA domain family members to regulate the proliferation and migration of retinal vascular endothelial cells (ECs), so YAP plays a prominent role in the formation and pathology of retinal vessels. In addition, YAP/TAZ activation and translocation to the nucleus promote endothelial inflammation and monocyte-EC attachment, which can increase diabetes-induced cardiovascular atherosclerosis. Hippo/YAP signaling pathway provides a potential therapeutic target for diabetic angiopathy, which can prevent the progression of diabetes to DR and improve renal fibrosis and cardio-vascular atherosclerosis.

Triptolide protects against podocyte injury in diabetic nephropathy by activating the Nrf2/HO-1 pathway and inhibiting the NLRP3 inflammasome pathway

Objectives: Diabetic nephropathy (DN) is the most common microvascular complication of diabetes mellitus. This study investigated the mechanism of triptolide (TP) in podocyte injury in DN.Methods: DN mouse models were established by feeding with a high-fat diet and injecting with streptozocin and MPC5 podocyte injury models were induced by high-glucose (HG), followed by TP treatment. Fasting blood glucose and renal function indicators, such as 24 h urine albumin (UAlb), serum creatinine (SCr), blood urea nitrogen (BUN), and kidney/body weight ratio of mice were examined. H&E and TUNEL staining were performed for evaluating pathological changes and apoptosis in renal tissue. The podocyte markers, reactive oxygen species (ROS), oxidative stress (OS), serum inflammatory cytokines, nuclear factor-erythroid 2-related factor 2 (Nrf2) pathway-related proteins, and pyroptosis were detected by Western blotting and corresponding kits. MPC5 cell viability and pyroptosis were evaluated by MTT and Hoechst 33342/PI double-fluorescence staining. Nrf2 inhibitor ML385 was used to verify the regulation of TP on Nrf2.Results: TP improved renal function and histopathological injury of DN mice, alleviated podocytes injury, reduced OS and ROS by activating the Nrf2/heme oxygenase-1 (HO-1) pathway, and weakened pyroptosis by inhibiting the nod-like receptor (NLR) family pyrin domain containing 3 (NLRP3) inflammasome pathway. In vitro experiments further verified the inhibition of TP on OS and pyroptosis by mediating the Nrf2/HO-1 and NLRP3 inflammasome pathways. Inhibition of Nrf2 reversed the protective effect of TP on MPC5 cells.Conclusions: Overall, TP alleviated podocyte injury in DN by inhibiting OS and pyroptosis via Nrf2/ROS/NLRP3 axis.

Network Pharmacology Analysis and Machine-Learning Models Confirmed the Ability of YiShen HuoXue Decoction to Alleviate Renal Fibrosis by Inhibiting Pyroptosis

Purpose

YiShen HuoXue decoction (YSHXD) is a formulation that has been used clinically for the treatment of renal fibrosis (RF) for many years. We aimed to clarify therapeutic effects of YSHXD against RF and potential pharmacological mechanisms.

Materials and Methods

We used network pharmacology analysis and machine-learning to screen the core components and core targets of YSHXD against RF, followed by molecular docking and molecular dynamics simulations to confirm the reliability of the results. Finally, we validated the network pharmacology analysis experimentally in HK-2 cells and a rat model of RF established by unilateral ureteral ligation (UUO).

Results

Quercetin, kaempferol, luteolin, beta-sitosterol, wogonin, stigmasterol, isorhamnetin, baicalein, and dihydrotanshinlactone progesterone were identified as the main active components of YSHXD in the treatment of unilateral ureteral ligation-induced RF, with IL-6, IL1β, TNF, AR, and PTGS2 as core target proteins. Molecular docking and molecular dynamics simulations further confirmed the relationship between compounds and target proteins. The potential molecular mechanism of YSHXD predicted by network pharmacology analysis was confirmed in HK-2 cells and UUO rats. YSHXD downregulated NLRP3, ASC, NF-κBp65, Caspase-1, GSDMD, PTGS2, IL-1β, IL-6, IL-18, TNF-α, α-SMA and upregulated HGF, effectively alleviating the RF process.

Conclusion

YSHXD exerts important anti-inflammatory and anti-cellular inflammatory necrosis effects by inhibiting the NLRP3/caspase-1/GSDMD-mediated pyroptosis pathway, indicating that YSHXD represents a new strategy and complementary approach to RF therapy.

Contribution of animal models to diabetes research: Its history, significance, and translation to humans

Diabetes mellitus is still expanding globally and is epidemic in developing countries. The combat of this plague has caused enormous economic and social burdens related to a lowered quality of life in people with diabetes. Despite recent significant improvements of life expectancy in patients with diabetes, there is still a need for efforts to elucidate the complexities and mechanisms of the disease processes to overcome this difficult disorder. To this end, the use of appropriate animal models in diabetes studies is invaluable for translation to humans and for the development of effective treatment. In this review, a variety of animal models of diabetes with spontaneous onset in particular will be introduced and discussed for their implication in diabetes research.

Recent advances in the pharmacological applications and liver toxicity of triptolide

Triptolide is a predominant active component of Triptergium wilfordii Hook. F, which has been used for the treatment of cancers and autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus and diabetic nephropathy. Therefore, triptolide and its derivates are considered to have promising prospects for development into drugs. However, the clinical application of triptolide is limited due to various organ toxicities, especially liver toxicity. The potential mechanism of triptolide-induced hepatotoxicity has attracted increasing attention. Over the past five years, studies have revealed that triptolide-induced liver toxicity is involved in metabolic imbalance, oxidative stress, inflammations, autophagy, apoptosis, and the regulation of cytochrome P450 (CYP450) enzymes, gut microbiota and immune cells. In this review, we summarize the pharmacological applications and hepatotoxicity mechanism of triptolide, which will provide solid theoretical evidence for further research of triptolide.

JAK/STAT signaling in diabetic kidney disease

Diabetic kidney disease (DKD) is the most important microvascular complication of diabetes and the leading cause of end-stage renal disease (ESRD) worldwide. The Janus kinase/signal transducer and activator of the transcription (JAK/STAT) signaling pathway, which is out of balance in the context of DKD, acts through a range of metabolism-related cytokines and hormones. JAK/STAT is the primary signaling node in the progression of DKD. The latest research on JAK/STAT signaling helps determine the role of this pathway in the factors associated with DKD progression. These factors include the renin-angiotensin system (RAS), fibrosis, immunity, inflammation, aging, autophagy, and EMT. This review epitomizes the progress in understanding the complicated explanation of the etiologies of DKD and the role of the JAK/STAT pathway in the progression of DKD and discusses whether it can be a potential target for treating DKD. It further summarizes the JAK/STAT inhibitors, natural products, and other drugs that are promising for treating DKD and discusses how these inhibitors can alleviate DKD to explore possible potential drugs that will contribute to formulating effective treatment strategies for DKD in the near future.

NF-κB pathway affects silica nanoparticle-induced fibrosis via inhibited inflammatory response and epithelial-mesenchymal transition in 3D co-culture

Long-term inhalation of silica nanoparticles (SiNPs) can induce pulmonary fibrosis (PF), nevertheless, the potential mechanisms remain elusive. Herein, we constructed a three-dimensional (3D) co-culture model by using Matrigel to investigate the interaction among different cells and potential regulatory mechanisms after SiNPs exposure. Methodologically, we dynamically observed the changes in cell morphology and migration after exposure to SiNPs by co-culturing mouse monocytic macrophages (RAW264.7), human non-small cell lung cancer cells (A549), and medical research council cell strain-5 (MRC-5) in Matrigel for 24 h. Subsequently, we detected the expression of nuclear factor kappa B (NF-κB), inflammatory factor and epithelial-mesenchymal transition (EMT) markers. The results showed that SiNPs produced toxic effects on cells. In the 3D co-culture state, the cell's movement velocity and displacement increased, and the cell migration ability was enhanced. Meanwhile, the expression of inflammatory factor tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) were upregulated, the epithelial marker E-cadherin (E-cad) was downregulated, the mesenchymal marker N-cadherin (N-cad) and myofibroblast marker alpha-smooth muscle actin (α-SMA) expression were upregulated, while NF-κB expression was also upregulated after SiNPs exposure. We further found that cells were more prone to transdifferentiate into myofibroblasts in the 3D co-culture state. Conversely, utilizing the NF-κB-specific inhibitor BAY 11-7082 effectively downregulated the expression of TNF-α, IL-6, interleukin-1β (IL-1β), N-cad, α-SMA, collagen-I (COL I), and fibronectin (FN), the expression of E-cad was upregulated. These findings suggest that NF-κB is involved in regulating SiNPs-induced inflammatory, EMT, and fibrosis in the 3D co-culture state.

Stem cell-derived exosomal MicroRNAs: Potential therapies in diabetic kidney disease

The diabetic kidney disease (DKD) is chronic kidney disease caused by diabetes and one of the most common comorbidities. It is often more difficult to treat end-stage renal disease once it develops because of its complex metabolic disorders, so early prevention and treatment are important. However, currently available DKD therapies are not ideal, and novel therapeutic strategies are urgently needed. The potential of stem cell therapies partly depends on their ability to secrete exosomes. More and more studies have shown that stem cell-derived exosomes take part in the DKD pathophysiological process, which may offer an effective therapy for DKD treatment. Herein, we mainly review potential therapies of stem cell-derived exosomes mainly stem cell-derived exosomal microRNAs in DKD, including their protective effects on mesangial cells, podocytes and renal tubular epithelial cells. Using this secretome as possible therapeutic drugs without potential carcinogenicity should be the focus of further research.

The emerging insight into E3 ligases as the potential therapeutic target for diabetic kidney disease

Diabetic kidney disease (DKD) is a major diabetic complication and global health concern, occurring in nearly 30 % to 40 % of people with diabetes. Importantly, several therapeutic strategies are being used against DKD; however, available treatments are not uniformly effective and the continuous rise in the prevalence of DKD demands more potential therapeutic approaches or targets. Epigenetic modifiers are regarded for their potential therapeutic effects against DKD. E3 ligases are such epigenetic modifier that regulates the target gene expression by attaching ubiquitin to the histone protein. In recent years, the E3 ligases came up as a potential therapeutic target as it selectively attaches ubiquitin to the substrate proteins in the ubiquitination cascade and modulates cellular homeostasis. The E3 ligases are also actively involved in DKD by regulating the expression of several proteins involved in the proinflammatory and profibrotic pathways. Burgeoning reports suggest that several E3 ligases such as TRIM18 (tripartite motif 18), Smurf1 (Smad ubiquitination regulatory factor 1), and NEDD4-2 (neural precursor cell-expressed developmentally downregulated gene 4-2) are involved in kidney epithelial-mesenchymal transition, inflammation, and fibrosis by regulating respective signaling pathways. However, the various signaling pathways that are regulated by different E3 ligases in the progression of DKD are poorly understood. In this review, we have discussed E3 ligases as potential therapeutic target for DKD. Moreover, different signaling pathways regulated by E3 ligases in the progression of DKD have also been discussed.

Friend or foe? The dual role of triptolide in the liver, kidney, and heart

Triptolide, a controversial natural compound due to its significant pharmacological activities and multiorgan toxicity, has gained much attention since it was isolated from the traditional Chinese herb Tripterygium wilfordii Hook F. However, in addition to its severe toxicity, triptolide also presents powerful therapeutic potency in the same organs, such as the liver, kidney, and heart, which corresponds to the Chinese medicine theory of You Gu Wu Yun (anti-fire with fire) and deeply interested us. To determine the possible mechanisms involved in the dual role of triptolide, we reviewed related articles about the application of triptolide in both physiological and pathological conditions. Inflammation and oxidative stress are the two main ways triptolide exerts different roles, and the cross-talk between NF-κB and Nrf2 may be one of the mechanisms responsible for the dual role of triptolide and may represent the scientific connotation of You Gu Wu Yun. For the first time, we present a review of the dual role of triptolide in the same organ and propose the possible scientific connotation of the Chinese medicine theory of You Gu Wu Yun, hoping to promote the safe and efficient use of triptolide and other controversial medicines.

Title: Bioinformatic Identification of Genes Involved in Diabetic Nephropathy Fibrosis and their Clinical Relevance

Tubulointerstitial fibrosis is an important pathological feature of diabetic nephropathy that is associated with impaired renal function. However, the mechanism by which fibrosis occurs in diabetic nephropathy is unclear. Differentially expressed genes were identified from transcriptome profiles of renal tissue from diabetic patients and unilateral ureteral obstruction mice and intersected to obtain genes that may be involved in diabetic fibrosis. Biological function analysis and protein-protein interaction network analysis were performed. ROC curve and Pearson correlation analysis between hub genes were performed and glomerular filtration rate estimated. Finally, the RNA levels of hub genes were measured using real-time PCR. A total of 283 genes were identified as potentially involved in diabetic nephropathy fibrosis. TYROBP, CTSS, LCP2, LUM and TLR7 were identified as aberrantly expressed hub genes. Immune cell infiltration analysis demonstrated higher numbers of cytotoxic lymphocytes, B lineage cells, monocyte lineage cells, myeloid dendritic cells, neutrophils, and fibroblasts in the diabetic nephropathy group. The areas under ROC curves for TYROBP, CTSS, LCP2, LUM and TLR7 were 0.9167, 0.9583, 0.9917, 0.93333, and 0.9583, respectively (P < 0.001), and their correlation coefficients with estimated glomerular filtration rate were - 0.8332, - 0.752, - 0.7875, - 0.7567, and - 0.7136, respectively (P < 0.001). The RNA levels of TYROBP, CTSS, LUM and TLR7 were upregulated in high-glucose-treated human renal tubular epithelial cells (P < 0.005). Our study identified TYROBP, CTSS, LCP2, LUM and TLR7 as potentially involved in diabetic nephropathy fibrosis. Furthermore, TYROBP, CTSS, LUM and TLR7 may be associated with epithelial-mesenchymal transition of tubular epithelial cells.

Urinary-derived extracellular vesicles reveal a distinct microRNA signature associated with the development and progression of Fabry nephropathy

Introduction

Early initiation is essential for successful treatment of Fabry disease, but sensitive and noninvasive biomarkers of Fabry nephropathy are lacking. Urinary extracellular vesicles (uEVs) represent a promising source of biomarkers of kidney involvement. Among them, microRNAs (miRNAs) are important post-transcriptional regulators of gene expression that contribute to the development and progression of various kidney diseases. We aimed to identify uEV-derived miRNAs involved in the development and/or progression of Fabry nephropathy.

Methods

Patients with genetically confirmed Fabry disease and matched control subjects were included. EVs were isolated from the second morning urine by size exclusion chromatography, from which miRNAs were extracted. miRNA urine exosome PCR panels were used to characterize the miRNA signature in a discovery cohort. Individual qPCRs were performed on a validation cohort that included chronological samples. We identified the target genes of dysregulated miRNAs and searched for potential hub genes. Enrichment analyses were performed to identify their potential function.

Results

The expression of miR-21-5p and miR-222-3p was significantly higher in patients with stable renal function and those with progressive nephropathy compared with the corresponding controls. In addition, the expression of miR-30a-5p, miR-10b-5p, and miR-204-5p was significantly lower in patients with progressive nephropathy, however, in the chronological samples, this was only confirmed for miR-204-5p. Some of the identified hub genes controlled by the dysregulated miRNAs have been associated with kidney impairment in other kidney diseases.

Conclusion

The miRNA cargo in uEVs changes with the development and progression of Fabry nephropathy and, therefore, represents a potential biomarker that may provide a new option to prevent or attenuate the progression of nephropathy. Furthermore, dysregulated miRNAs were shown to be potentially associated with pathophysiological pathways in the kidney.

What's New in the Molecular Mechanisms of Diabetic Kidney Disease: Recent Advances

Diabetic kidney disease (DKD) is the leading cause of chronic kidney disease, including end-stage kidney disease, and increases the risk of cardiovascular mortality. Although the treatment options for DKD, including angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, sodium-glucose cotransporter 2 inhibitors, and mineralocorticoid receptor antagonists, have advanced, their efficacy is still limited. Thus, a deeper understanding of the molecular mechanisms of DKD onset and progression is necessary for the development of new and innovative treatments for DKD. The complex pathogenesis of DKD includes various different pathways, and the mechanisms of DKD can be broadly classified into inflammatory, fibrotic, metabolic, and hemodynamic factors. Here, we summarize the recent findings in basic research, focusing on each factor and recent advances in the treatment of DKD. Collective evidence from basic and clinical research studies is helpful for understanding the definitive mechanisms of DKD and their regulatory systems. Further comprehensive exploration is warranted to advance our knowledge of the pathogenesis of DKD and establish novel treatments and preventive strategies.

DNA methyltransferase 1 knockdown reverses PTEN and VDR by mediating demethylation of promoter and protects against renal injuries in hepatitis B virus-associated glomerulonephritis

Background

Aberrant DNA methylation patterns, including hypermethylation of key genes that inhibit fibrosis and inflammation, have been described in human kidney diseases. However, the role of DNA methyltransferase 1 (DNMT1) in hepatitis B virus-associated glomerulonephritis (HBV-GN) remains unclear.

Methods

We explored the underlying mechanism by establishing HBV X protein (HBx) overexpressing renal tubular epithelial (HK-2) cells and human podocytes with DNMT1 knockdown. Using RNA-sequencing to determine the downstream targets of DNMT1 and evaluate its levels of promoter methylation. HBV transgenic mice were used to examine the effects of DNMT1 inhibitor on renal in vivo.

Results

DNMT1 was significantly upregulated in the renal tissue of HBV-GN patients, accompanied by injuries of HK-2 cells and podocytes. HBx markedly upregulated DNMT1 and induced epithelial-mesenchymal transition (EMT) and inflammation in HK-2 cells and human podocytes. This increased DNMT1 expression was attenuated after DNMT1 knockdown, accompanied by restored HK-2 cells and podocyte injuries resulting from the activation of PI3K/Akt/mTOR and nuclear factor-kappa B (NF-κB) pathways. Hypermethylation of the phosphatase and tensin homolog (PTEN) promoter and vitamin D receptor (VDR) was induced in HBx-overexpressing HK-2 cells and podocytes, respectively, whereas DNMT1 knockdown effectively corrected these alterations. Furthermore, PTEN and VDR ablation resulted in marked EMT and inflammation induction in HBx-overexpressing HK-2 cells and human podocytes even with DNMT1 knockdown. Downregulation of the PI3K/Akt/mTOR-related pathway attenuated HBx-induced EMT and inflammation in HK-2 cells. Luciferase reporter assay revealed VDR as a direct target of the Snail family transcriptional repressor 1 (SNAI1) in HBx-overexpressing podocytes. DNA methylation inhibitor 5-azacytidine alleviated urinary protein and renal inflammation in HBV transgenic mice via PTEN-PI3K/Akt signaling and VDR signaling axis.

Conclusions

Our study clarifies the potential epigenetic mechanisms underlying HBx-induced renal injuries in HBV-GN and the renoprotective effects of inhibiting DNMT1, which can provide important insights into the development of treatments for HBV-GN.

Loss of Pten in Renal Tubular Cells Leads to Water Retention by Upregulating AQP2

Introduction

Phosphatase and tensin (PTEN) is a multifunctional gene associated with the normal development and physiological function of various tissues including the kidney. However, its role in renal tubular reabsorption function has not been well elucidated.

Methods

We generated a renal tubule-specific Pten knockout mouse model by crossing Pten^fl/fl mice with Ksp-Cre transgenic mice, evaluated the effect of Pten loss on renal tubular function, and investigated the underlying mechanisms.

Results

Pten loss resulted in abnormal renal structure and function and water retention in multiple organs. Our results also demonstrated that aquaporin-2 (AQP2), an important water channel protein, was upregulated and concentrated on the apical plasma membrane of collecting duct cells, which could be responsible for the impaired water balance in Pten loss mice. The regulation of Pten loss on AQP2 was mediated by protein kinase B (AKT) activation.

Conclusions

Our results reveal a connection between PTEN gene inactivation and water retention, suggesting the importance of PTEN in normal kidney development and function.

IL-18 deficiency ameliorates the progression from AKI to CKD

Inflammation is an important factor in the progression from acute kidney injury (AKI) to chronic kidney disease (CKD). The role of interleukin (IL)-18 in this progression has not been examined. We aimed to clarify whether and how IL-18 limits this progression. In a folic acid induced renal injury mouse model, we studied the time course of kidney injury and renal IL-18 expression. In wild-type mice following injection, renal IL-18 expression increased. In parallel, we characterized other processes, including at day 2, renal tubular necroptosis assessed by receptor-interacting serine/threonine-protein kinase1 (RIPK1) and RIPK3; at day 14, transdifferentiation (assessed by transforming growth factor β1, vimentin and E-cadherin); and at day 30, fibrosis (assessed by collagen 1). In IL-18 knockout mice given folate, compared to wild-type mice, tubular damage and necroptosis, transdifferentiation, and renal fibrosis were attenuated. Importantly, IL-18 deletion decreased numbers of renal M1 macrophages and M1 macrophage cytokine levels at day 14, and reduced M2 macrophages numbers and macrophage cytokine expression at day 30. In HK-2 cells, IL-18 knockdown attenuated necroptosis, transdifferentiating and fibrosis.In patients with tubulointerstitial nephritis, IL-18 protein expression was increased on renal biopsies using immunohistochemistry. We conclude that genetic IL-18 deficiency ameliorates renal tubular damage, necroptosis, cell transdifferentiation, and fibrosis. The renoprotective role of IL-18 deletion in the progression from AKI to fibrosis may be mediated by reducing a switch in predominance from M1 to profibrotic M2 macrophages during the process of kidney repair.

Cellular phenotypic transitions in diabetic nephropathy: An update

Diabetic nephropathy (DN) is a major cause of morbidity and mortality in diabetes and is the most common cause of end stage renal disease (ESRD). Renal fibrosis is the final pathological change in DN. It is widely believed that cellular phenotypic switching is the cause of renal fibrosis in diabetic nephropathy. Several types of kidney cells undergo activation and differentiation and become reprogrammed to express markers of mesenchymal cells or podocyte-like cells. However, the development of targeted therapy for DN has not yet been identified. Here, we discussed the pathophysiologic changes of DN and delineated the possible origins that contribute to myofibroblasts and podocytes through phenotypic transitions. We also highlight the molecular signaling pathways involved in the phenotypic transition, which would provide valuable information for the activation of phenotypic switching and designing effective therapies for DN.

Mechanism of Tripterygium wilfordii Hook.F.- Trichosanthes kirilowii Maxim decoction in treatment of diabetic kidney disease based on network pharmacology and molecular docking

Background: Diabetic kidney disease (DKD) is the most common cause of end-stage renal disease. The effective treatment of DKD would rely on the incorporation of a multi-disciplinary. Studies have shown that Tripterygium wilfordii Hook.F. and Trichosanthes kirilowii Maxim have remarkable curative effects in treating DKD, but their combination mechanism has not been fully elucidated.

Methods: We explored the mechanism of Tripterygium wilfordii Hook.F.-Trichosanthes kirilowii Maxim decoction (Leigongteng-Tianhuafen Decoction,LTD) in the treatment of DKD by network pharmacology and molecular docking. The main active components and action targets of LTD were collected from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) database. The speculative targets of DKD were obtained from GeneCards, DisGeNET, and Online Mendelian Inheritance in Man (OMIM) databases. Then, an herb-component-target network was constructed based on the above analyses. The biological function of targets was subsequently investigated, and a protein-protein interaction (PPI) network was constructed to identify hub targets of DKD. The gene ontology (GO) function enrichment analysis and kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analysis were performed by RStudio. Finally, molecular docking was performed by AutoDock Vina and PyMOL software to explore the interaction between compounds and targets. Furthermore, the DKD model of human renal tubular cells (HK-2) induced by high glucose (HG) was selected, and the predicted results were verified by western blot analysis and immunofluorescence.

Results: A total of 31 active components of LTD were screened out, and 196 targets were identified based on the TCMSP database. A total of 3,481 DKD related targets were obtained based on GeneCards, DisGeNET, and OMIM databases. GO function enrichment analysis included 2,143, 50, and 167 GO terms for biological processes (BPs), cellular composition (CCs), and molecular functions (MFs), respectively. The top 10 enrichment items of BP annotations included response to lipopolysaccharide, response to molecule of bacterial origin, response to extracellular stimulus, etc. CC was mainly enriched in membrane raft, membrane microdomain, plasma membrane raft, etc. The MF of LTD analysis on DKD was predominately involved in nuclear receptor activity, ligand-activated transcription factor activity, RNA polymerase II-specific DNA-binding transcription factor binding, etc. The involvement signaling pathway of LTD in the treatment of DKD included AGE-RAGE signaling pathway in diabetic complications, IL-17 signaling pathway, insulin resistance, TNF signaling pathway, etc. Molecular docking results showed that kaempferol, triptolide, nobiletin, and schottenol had a strong binding ability to PTGS2 and RELA. Furthermore, the in vitro experiments confirmed that LTD effectively decreased the expression of PTGS2, NF-κB, JNK, and AKT in the HG-induced DKD model.

Conclusion: The findings of this study revealed that the therapeutic efficacy of LTD on DKD might be achieved by decreasing the expression of PTGS2, NF-κB, JNK, and AKT, which might improve insulin resistance, inflammation, and oxidative stress. These findings can provide ideas and supply potential therapeutic targets for DKD.

hucMSC-sEVs-Derived 14-3-3ζ Serves as a Bridge between YAP and Autophagy in Diabetic Kidney Disease

As nanoscale membranous vesicles, human umbilical cord mesenchymal stem cell-derived small extracellular vesicles (hucMSC-sEVs) have attracted extensive attention in the field of tissue regeneration. Under the premise that the mechanisms of hucMSC-sEVs on the treatment of diabetic kidney disease (DKD) have not been revealed clearly, we constructed DKD rat model with success. After tail vein injection, hucMSC-sEVs effectively reduced blood glucose, maintained body weight and improved renal function in DKD rats. Notably, we found that hucMSC-sEVs suppressed YAP expression in renal cortical regions. Further in vitro experiments, we confirmed that the expression of YAP in the nucleus of renal podocytes was increased, and the level of autophagy was inhibited in the high-glucose environment, which could be reversed by intervention with hucMSC-sEVs. We screened out the key protein 14-3-3ζ, which could not only promote YAP cytoplasmic retention instead of entering the nucleus, but also enhance the level of autophagy in the cytoplasm. Ultimately, excessive YAP protein was removed by autophagy, a classic way of protein degradation. In conclusion, our study provides new strategies for the prevention of DKD and proposes the possibility of hucMSC-sEVs becoming a new treatment for DKD in the future.

Natural products: potential drugs for the treatment of renal fibrosis

With the increasing prevalence and mortality, chronic kidney disease (CKD) has become a world public health problem. As the primary pathological manifestation in CKD, renal fibrosis is often used as a critical target for the treatment of CKD and inhibits the progression of CKD to end-stage renal disease (ESRD). As a potential drug, natural products have been confirmed to have the potential as a routine or supplementary therapy for chronic kidney disease, which may target renal fibrosis and act through various pharmacological activities such as anti-inflammatory and anti-oxidation of natural products. This article briefly introduces the pathological mechanism of renal fibrosis and systematically summarizes the latest research on the treatment of renal fibrosis with natural products of Chinese herbal medicines.

Triptolide promotes autophagy to inhibit mesangial cell proliferation in IgA nephropathy via the CARD9/p38 MAPK pathway

Background

Mesangial cell proliferation is the most basic pathological feature of immunoglobulin A nephropathy (IgAN); however, the specific underlying mechanism and an appropriate therapeutic strategy are yet to be unearthed. This study aimed to investigate the therapeutic effect of triptolide (TP) on IgAN and the mechanism by which TP regulates autophagy and proliferation of mesangial cells through the CARD9/p38 MAPK pathway.

Methods

We established a TP‐treated IgAN mouse model and produced IgA1‐induced human mesangial cells (HMC) and divided them into control, TP, IgAN, and IgAN+TP groups. The levels of mesangial cell proliferation (PCNA, cyclin D1, cell viability, and cell cycle) and autophagy (P62, LC3 II, and autophagy flux rate) were measured, with the autophagy inhibitor 3‐Methyladenine used to explore the relationship between autophagy and proliferation. We observed CARD9 expression in renal biopsies from patients and analyzed its clinical significance. CARD9 siRNA and overexpression plasmids were constructed to investigate the changes in mesangial cell proliferation and autophagy as well as the expression of CARD9 and p‐p38 MAPK/p38 MAPK following TP treatment.

Results

Administering TP was safe and effectively alleviated mesangial cell proliferation in IgAN mice. Moreover, TP inhibited IgA1‐induced HMC proliferation by promoting autophagy. The high expression of CARD9 in IgAN patients was positively correlated with the severity of HMC proliferation. CARD9/p38 MAPK was involved in the regulation of HMC autophagy and proliferation, and TP promoted autophagy to inhibit HMC proliferation by downregulating the CARD9/p38 MAPK pathway in IgAN.

Conclusion

TP promotes autophagy to inhibit mesangial cell proliferation in IgAN via the CARD9/p38 MAPK pathway.

Astragaloside IV Alleviates Renal Tubular Epithelial-Mesenchymal Transition via CX3CL1-RAF/MEK/ERK Signaling Pathway in Diabetic Kidney Disease

Background

Epithelial–mesenchymal transition (EMT) plays an important role in interstitial matrix deposition and renal fibrosis in diabetic kidney disease (DKD). It has been verified that Astragaloside IV (AS-IV) is beneficial for ameliorating DKD. However, the underlying mechanisms of AS-IV on regulating EMT in DKD are yet to be established. Accumulated evidence has suggested that C-X3-C motif ligand 1 (CX3CL1) plays a significant role in the progression of EMT.

Purpose

We aimed to investigate whether AS-IV could alleviate EMT by regulating CX3CL1 in DKD and reveal its underlying mechanisms.

Methods

For the in vivo study, mice were divided into the following five groups (n=10): db/m+vehicle, db/db+vehicle, db/db+AS-IV-L (10mg/kg/d), db/db+AS-IV-M (20mg/kg/d), db/db+AS-IV-H (40mg/kg/d). After 12 weeks of treatment, the renal injuries were assessed based on the related parameters of urine, blood and histopathological examination. Immunohistochemistry and Western blotting were used to detect relative proteins levels. Then in HK-2 cells, the molecular mechanism of AS-IV attenuating the EMT in mice with DKD through the CX3CL1-RAF/MEK/ERK pathway was studied.

Results

In the present study, we found that AS-IV reduced urinary protein levels and improved renal pathological damage in DKD mice. Moreover, AS-IV ameliorated the renal tubular EMT induced by hyperglycemia or high glucose (HG), and decreased the expression of CX3CL1 and inhibited the activation of the RAF/MEK/ERK pathway in vivo and in vitro. In HK-2 cells, downregulation of CX3CL1 suppressed the stimulation of the RAF/MEK/ERK pathway and EMT induced by HG. However, CX3CL1 overexpression eliminated the benefits of AS-IV on the RAF/MEK/ERK pathway and EMT.

Conclusion

In summary, we indicated that AS-IV alleviates renal tubular EMT through the CX3CL1-RAF/MEK/ERK signaling pathway, indicating that CX3CL1 could be a potential therapeutic target of AS-IV in DKD.

Mechanism for the therapeutic effect of Tripterygium wilfordii Hook. f. preparations on IgA nephropathy

Tripterygium wilfordii Hook. f. is a traditional Chinese herbal medicine. The bioactive compounds from Tripterygium wilfordii Hook. f. have unique immunosuppressive and anti-inflammatory effects, and can exert their pharmacological effects through multi-target and multi-channel. Tripterygium wilfordii Hook. f. preparations have been used in IgA nephropathy (IgAN) for many years and are well accepted for good curative effects. However, the underlying mechanisms are still unclear. It is valuable to summarize the current progress in clinical application of Tripterygium wilfordii Hook. f. preparations in IgAN and other kidney diseases. We discussed the component characteristics, efficacies in reducing urinary protein levels and protecting renal function, as well as the side effects. As for the mechanisms, we should focus on all links of IgAN pathogenesis, including reducing the production of pathogenic IgA, decreasing renal inflammation and fibrosis, and protecting podocytes. As a representative drugs with clear efficacy and potential toxicity, Tripterygium wilfordii Hook. f. preparations need more in-depth basic and clinical research to improve their efficacy and safety.

Epithelial-mesenchymal transition in organ fibrosis development: current understanding and treatment strategies

Organ fibrosis is a process in which cellular homeostasis is disrupted and extracellular matrix is excessively deposited. Fibrosis can lead to vital organ failure and there are no effective treatments yet. Although epithelial–mesenchymal transition (EMT) may be one of the key cellular mechanisms, the underlying mechanisms of fibrosis remain largely unknown. EMT is a cell phenotypic process in which epithelial cells lose their cell-to-cell adhesion and polarization, after which they acquire mesenchymal features such as infiltration and migration ability. Upon injurious stimulation in different organs, EMT can be triggered by multiple signaling pathways and is also regulated by epigenetic mechanisms. This narrative review summarizes the current understanding of the underlying mechanisms of EMT in fibrogenesis and discusses potential strategies for attenuating EMT to prevent and/or inhibit fibrosis. Despite better understanding the role of EMT in fibrosis development, targeting EMT and beyond in developing therapeutics to tackle fibrosis is challenging but likely feasible.

Serum Level of Polyubiquitinated PTEN and Loss of Kidney Function in American Indians With Type 2 Diabetes

RATIONALE & OBJECTIVE

Fibrosis is a major driver of chronic kidney disease, and epithelial-mesenchymal transition (EMT) may contribute to its development. A polyubiquitinated form of phosphatase and tensin homolog (PTEN^K27polyUb) promotes EMT in vitro. Thus, it is a potentially useful biomarker of progressive kidney fibrosis and may predict loss of kidney function.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

Southwest United States, American Indians (154 women, 80 men) with or at high risk for diabetic kidney disease (DKD).

PREDICTORS

Serum level of PTEN^K27polyUb.

OUTCOME

≥40% loss of glomerular filtration rate (GFR) or onset of kidney failure. Kidney structural measures in a subset of study participants who underwent research kidney biopsies (n = 77).

ANALYTICAL APPROACH

Cox proportional hazards models adjusted for age, sex, diabetes duration, hemoglobin A_1c (HbA_1c), blood pressure, use of renin angiotensin system (RAS) blockers, measured GFR, and albuminuria. Spearman correlations for associations with structural measures.

RESULTS

At baseline, the participants' mean age was 42.8 ± 10.5 (SD) years, diabetes duration 11.5 ± 7.1 years, mean arterial pressure 90.5 ± 9.5 mm Hg, HbA_1c 9.3 ± 2.4%, GFR 152 ± 45 mL/min, and median urinary albumin-creatinine ratio 38 (interquartile range, 14-215) mg/g. RAS blockers were being used by 64 participants (27.4%). A higher PTEN^K27polyUb value was associated with a greater risk of ≥40% loss of GFR during a median follow-up period of 6.3 years (HR for quartile 4 [Q4] vs Q1, 3.95 [95% CI, 2.23-6.98], P < 0.001). Serum PTEN^K27polyUb was associated with an increased risk of kidney failure over a median follow-up period of 15.8 years (HR for Q4 vs Q1, 5.66 [95% CI, 1.99-16.13], P = 0.001). Baseline serum PTEN^K27polyUb in the biopsy subset correlated with structural measures including glomerular basement membrane width (ρ = 0.370, P < 0.001) and mesangial fractional volume (ρ = 0.392, P < 0.001).

LIMITATIONS

Small study in single population.

CONCLUSIONS

Higher serum PTEN^K27polyUb is associated with increased risk for GFR decline and kidney failure in American Indians with type 2 diabetes.

The role of PTEN in puromycin aminonucleoside-induced podocyte injury

Podocytes are specialized cells of the glomerulus that play important structural and functional roles in maintaining the filtration barrier. Loss and injury of podocytes are leading factors of glomerular disease and kidney failure. Recent studies found that phosphatase and tensin homolog (PTEN) may play a critical role in maintaining the normal structure and function in podocytes. However, we still understand very little about how PTEN is regulated under podocyte injury conditions. In this study, We therefore investigated whether PTEN could play a role in podocyte injury induced by puromycin aminonucleoside (PAN), and whether dexamethasone (DEX) alleviates podocyte injury by PTEN/PI3K/Akt signaling. Our results showed that PI3K/Akt pathway was activated in podocytes exposed to PAN conditions, accompanied by down-regulation of the PTEN and microtubule-associated light chain 3 (LC3) expression.podocyte-specific knockout of PTEN significantly promoted podocyte injury, The potential renoprotection of overexpressed PTEN in podocytes was partly attributed with an improvement in autophagy and the inhibition of apoptosis.These novel findings also suggest that targeting PTEN might be a novel and promising therapeutic strategy against podocyte injury.

All-in-One: Multifunctional Hydrogel Accelerates Oxidative Diabetic Wound Healing through Timed-Release of Exosome and Fibroblast Growth Factor

The treatment of diabetic wounds remains a major challenge in clinical practice, with chronic wounds characterized by multiple drug-resistant bacterial infections, angiopathy, and oxidative damage to the microenvironment. Herein, a novel in situ injectable HA@MnO₂ /FGF-2/Exos hydrogel is introduced for improving diabetic wound healing. Through a simple local injection, this hydrogel is able to form a protective barrier covering the wound, providing rapid hemostasis and long-term antibacterial protection. The MnO₂ /ε-PL nanosheet is able to catalyze the excess H₂ O₂ produced in the wound, converting it to O₂ , thus not only eliminating the harmful effects of H₂ O₂ but also providing O₂ for wound healing. Moreover, the release of M2-derived Exosomes (M2 Exos) and FGF-2 growth factor stimulates angiogenesis and epithelization, respectively. These in vivo and in vitro results demonstrate accelerated healing of diabetic wounds with the use of the HA@MnO₂ /FGF-2/Exos hydrogel, presenting a viable strategy for chronic diabetic wound repair.

PTEN alleviates maladaptive repair of renal tubular epithelial cells by restoring CHMP2A-mediated phagosome closure

Phosphatase and Tensin Homolog on chromosome Ten (PTEN) has emerged as a key protein that governs the response to kidney injury. Notably, renal adaptive repair is important for preventing acute kidney injury (AKI) to chronic kidney disease (CKD) transition. To test the role of PTEN in renal repair after acute injury, we constructed a mouse model that overexpresses PTEN in renal proximal tubular cells (RPTC) by crossing PTEN^fl-stop-fl mice with Ggt1-Cre mice. Mass spectrometry-based proteomics was performed after subjecting these mice to ischemia/reperfusion (I/R). We found that PTEN was downregulated in renal tubular cells in mice and cultured HK-2 cells subjected to renal maladaptive repair induced by I/R. Renal expression of PTEN negatively correlated with NGAL and fibrotic markers. RPTC-specific PTEN overexpression relieved I/R-induced maladaptive repair, as indicated by alleviative tubular cell damage, apoptosis, and subsequent renal fibrosis. Mass spectrometry analysis revealed that differentially expressed proteins in RPTC-specific PTEN overexpression mice subjected to I/R were significantly enriched in phagosome, PI3K/Akt, and HIF-1 signaling pathway and found significant upregulation of CHMP2A, an autophagy-related protein. PTEN deficiency downregulated CHMP2A and inhibited phagosome closure and autolysosome formation, which aggravated cell injury and apoptosis after I/R. PTEN overexpression had the opposite effect. Notably, the beneficial effect of PTEN overexpression on autophagy flux and cell damage was abolished when CHMP2A was silenced. Collectively, our study suggests that PTEN relieved renal maladaptive repair in terms of cell damage, apoptosis, and renal fibrosis by upregulating CHMP2A-mediated phagosome closure, suggesting that PTEN/CHMP2A may serve as a novel therapeutic target for the AKI to CKD transition.

The Efficacy of Triptolide in Preventing Diabetic Kidney Diseases: A Systematic Review and Meta-Analysis

Ethnopharmacological Relevance: Triptolide (TP), the primary biologically active ingredient of Tripterygium wilfordii Hook F (TWHF), possesses the potential to solve the shortcomings of TWHF in treating diabetic kidney disease (DKD) in the clinic.

Aim of the Study: We conducted a meta-analysis to evaluate the efficacy of TP in treating DKD and offer solid evidence for further clinical applications of TP.

Materials and Methods: Eight databases (CNKI, VIP, CBM, WanFang, PubMed, Web of Science, EMBASE, and Cochrane library) were electronically searched for eligible studies until October 17, 2020. We selected animal experimental studies using TP versus renin–angiotensin system inhibitors or nonfunctional liquids to treat DKD by following the inclusion and exclusion criteria. Two researchers independently extracted data from the included studies and assessed the risk of bias with the Systematic Review Centre for Laboratory Animal Experimentation Risk of Bias tool. Fixed-effects meta-analyses, subgroup analyses, and meta-regression were conducted using RevMan 5.3 software. Inplasy registration number: INPLASY2020100042.

Results: Twenty-six studies were included. Meta-analysis showed that TP significantly reduced albuminuria (14 studies; standardized mean difference SMD: −1.44 [−1.65, −1.23], I² = 87%), urine albumin/urine creatinine ratio (UACR) (8 studies; SMD: –5.03 [–5.74, −4.33], I² = 84%), total proteinuria (4 studies; SMD: –3.12 [–3.75, −2.49], I² = 0%), serum creatinine (18 studies; SMD: –0.30 [–0.49, −0.12], I² = 76%), and blood urea nitrogen (12 studies; SMD: –0.40 [–0.60, −0.20], I² value = 55%) in DKD animals, compared to the vehicle control. However, on comparing TP to the renin–angiotensin system (RAS) inhibitors in DKD treatment, there was no marked difference in ameliorating albuminuria (3 studies; SMD: –0.35 [–0.72, 0.02], I² = 41%), serum creatinine (3 studies; SMD: –0.07 [–0.62, 0.48], I² = 10%), and blood urea nitrogen (2 studies; SMD: –0.35 [–0.97, 0.28], I² = 0%). Of note, TP exhibited higher capacities in reducing UACR (2 studies; SMD: –0.66 [–1.31, −0.01], I² = 0%) and total proteinuria (2 studies; SMD: –1.18 [–1.86, −2049], I² = 0%). Meta-regression implicated that the efficacy of TP in reducing DKD albuminuria was associated with applied dosages. In addition, publication bias has not been detected on attenuating albuminuria between TP and RAS inhibitors after the diagnosis of DKD.

Systematic Review Registration:https://clinicaltrials.gov/, identifier INPLASY2020100042

The Active Compounds and Therapeutic Target of Tripterygium wilfordii Hook. f. in Attenuating Proteinuria in Diabetic Nephropathy: A Review

Tripterygium wilfordii Hook. f. (TWHF) is a traditional Chinese herbal medicine and widely used to treat diabetic kidney disease in China. Emerging evidences have revealed its ability to attenuate diabetic nephropathy (DN). Tripterygium wilfordii polyglycosides (TWPs), triptolide (TP), and celastrol are predominantly active compounds isolated from TWHF. The effects and molecular mechanisms of TWHF and its active compounds have been investigated in recent years. Currently, it is becoming clearer that the effects of TWHF and its active compounds involve in anti-inflammation, anti-oxidative stress, anti-fibrosis, regulating autophagy, apoptosis, and protecting podocytes effect. This review presents an overview of the current findings related to the effects and mechanisms of TWHF and its active compounds in therapies of DN, thus providing a systematic understanding of the mechanisms and therapeutic targets by which TWHF and its active compounds affect cells and tissues in vitro and in vivo.

Epithelial-to-Mesenchymal Transition in Fibrosis: Concepts and Targeting Strategies

The epithelial-to-mesenchymal transition (EMT), an embryonic program relaunched during wound healing and in pathological conditions such as fibrosis and cancer, continues to gain the attention of the research community, as testified by the exponential trend of publications since its discovery in the seventies. From the first description as a mesenchymal transformation, the concept of EMT has been substantially refined as an in-depth comprehension of its functional role has recently emerged thanks to the implementation of novel mouse models as well as the use of sophisticated mathematical modeling and bioinformatic analysis. Nevertheless, attempts to targeting EMT in fibrotic diseases are at their infancy and continue to pose several challenges. The aim of this mini review is to recapitulate the most recent concepts in the EMT field and to summarize the different strategies which have been exploited to target EMT in fibrotic disorders.

Exploring the Potential Mechanism of Tang-Shen-Ning Decoction against Diabetic Nephropathy Based on the Combination of Network Pharmacology and Experimental Validation

Background

Diabetic nephropathy (DN) has become one of the leading causes of the end-stage renal disease (ESRD). Tang-Shen-Ning (TSN) decoction, an effective Traditional Chinese formula for DN, can improve the renal function and inhibit renal fibrosis in DN. However, its potential mechanism is still unexplored.

Methods

A network pharmacology approach was employed in this study, including screening for differential expressed genes of DN (DN-DEGs), protein-protein interaction (PPI) network analysis, and GO and KEGG enrichment analysis. Besides, a rat model was established to verify the potential effect of TSN in DN.

Results

Twenty-three TSN-related DN-DEGs targets were identified. These genes were associated with decreased glomerular filtration rate (GFR) DN. The enrichment analysis suggested that the inhibition of renal fibrosis and inflammation through growth factors and chemokines is the potential mechanism through which TSN improves DN. TSN reduced renal fibrosis and improved pathological damage in the kidney in vivo through the regulation of GJA1, CTGF, MMP7, and CCL5, which are genes associated with ECM deposition.

Conclusion

This study revealed that TSN improves DN through a multicomponent, multitarget, and multipathway synergy. We provide a scientific basis for potential targets for TSN use to treat DN, yet further experimental validation is needed to investigate these targets and mechanisms.

Tandem Ubiquitin Binding Entities (TUBEs) as Tools to Explore Ubiquitin-Proteasome System and PROTAC Drug Discovery

The ubiquitin proteasome system (UPS) is a complex pathway that involves multiple enzymes and culminates in the formation of a polyubiquitin chain on a target protein. As its importance is becoming more evident in drug discovery, there is a renewed interest in understanding the role that polyubiquitin chains play. This has been a challenge, mostly due to the lack of experimental tools for detecting the polyubiquitinated forms of a protein of interest (POI). Tandem Ubiquitin Binding Entities (TUBEs) are engineered protein domains that bind specifically to polyubiquitin chains. These polyubiquitin affinity matrices are highly sensitive as they bind to polyubiquitin chains in the nanomolar range. They exist in two forms: pan-selective TUBEs and chain-selective TUBEs. The ability of TUBEs to be conjugated to different entities is truly what makes them unique. TUBEs are used in a wide variety of experiments such as in protein pulldowns to enrich for polyubiquitinated proteins. They are an alternative to ubiquitin antibodies in Western blots. Further, TUBEs are used as capture reagents for immobilizing polyubiquitinated proteins on a microtiter plate. The use of TUBEs as components of in vitro and cell-based assays presents the unique feature of confirming and assessing the polyubiquitination of a POI in response to inhibitors, activators, or PROTAC^® molecules. Therefore, TUBEs not only play a big role in studying the UPS but also have a huge potential for speeding up the drug discovery process.

Partial EMT in Squamous Cell Carcinoma: A Snapshot

In the process of cancer EMT, some subgroups of cancer cells simultaneously exhibit both mesenchymal and epithelial characteristics, a phenomenon termed partial EMT (pEMT). pEMT is a plastic state in which cells coexpress epithelial and mesenchymal markers. In squamous cell carcinoma (SCC), pEMT is regulated, and the phenotype is maintained via the HIPPO pathway, NOTCH pathway and TGF-β pathways and by microRNAs, lncRNAs and the cancer microenvironment (CME); thus, SCC exhibits aggressive tumorigenic properties and high stemness, which leads collective migration and therapy resistance. Few studies have reported therapeutic interventions to address cells that have undergone pEMT, and this approach may be an effective way to inhibit the plasticity, drug resistance and metastatic potential of SCC.

An easy-to-operate web-based calculator for predicting the progression of chronic kidney disease

BACKGROUND

This study aimed to establish and validate an easy-to-operate novel scoring system based on simple and readily available clinical indices for predicting the progression of chronic kidney disease (CKD).

METHODS

We retrospectively evaluated 1045 eligible CKD patients from a publicly available database. Factors included in the model were determined by univariate and multiple Cox proportional hazard analyses based on the training set.

RESULTS

Independent prognostic factors including etiology, hemoglobin level, creatinine level, proteinuria, and urinary protein/creatinine ratio were determined and contained in the model. The model showed good calibration and discrimination. The area under the curve (AUC) values generated to predict 1-, 2-, and 3-year progression-free survival in the training set were 0.947, 0.931, and 0.939, respectively. In the validation set, the model still revealed excellent calibration and discrimination, and the AUC values generated to predict 1-, 2-, and 3-year progression-free survival were 0.948, 0.933, and 0.915, respectively. In addition, decision curve analysis demonstrated that the model was clinically beneficial. Moreover, to visualize the prediction results, we established a web-based calculator ( https://ncutool.shinyapps.io/CKDprogression/ ).

CONCLUSION

An easy-to-operate model based on five relevant factors was developed and validated as a conventional tool to assist doctors with clinical decision-making and personalized treatment.

Study of the Active Components and Molecular Mechanism of Tripterygium wilfordii in the Treatment of Diabetic Nephropathy

We aimed to explore the active ingredients and molecular mechanism of Tripterygium wilfordii (TW) in the treatment of diabetic nephropathy (DN) through network pharmacology and molecular biology. First, the active ingredients and potential targets of TW were obtained through the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) and related literature materials, and Cytoscape 3.7.2 software was used to construct the active ingredient-target network diagram of TW. Second, the target set of DN was obtained through the disease database, and the potential targets of TW in the treatment of DN were screened through a Venn diagram. A protein interaction network diagram (PPI) was constructed with the help of the String platform and Cytoscape 3.7.2. Third, the ClueGO plug-in tool was used to enrich the GO biological process and the KEGG metabolic pathway. Finally, molecular docking experiments and cell pathway analyses were performed. As a result, a total of 52 active ingredients of TW were screened, and 141 predicted targets and 49 target genes related to DN were identified. The biological process of GO is mediated mainly through the regulation of oxygen metabolism, endothelial cell proliferation, acute inflammation, apoptotic signal transduction pathway, fibroblast proliferation, positive regulation of cyclase activity, adipocyte differentiation and other biological processes. KEGG enrichment analysis showed that the main pathways involved were AGE-RAGE, vascular endothelial growth factor, HIF-1, IL-17, relaxin signalling pathway, TNF, Fc epsilon RI, insulin resistance and other signaling pathways. It can be concluded that TW may treat DN by reducing inflammation, reducing antioxidative stress, regulating immunity, improving vascular disease, reducing insulin resistance, delaying renal fibrosis, repairing podocytes, and reducing cell apoptosis, among others, with multicomponent, multitarget and multisystem characteristics.

Oncogenic Potential of the Dual-Function Protein MEX3A

MEX3A belongs to the MEX3 (Muscle EXcess) protein family consisting of four members (MEX3A-D) in humans. Characteristic for MEX3 proteins is their domain structure with 2 HNRNPK homology (KH) domains mediating RNA binding and a C-terminal really interesting new gene (RING) domain that harbors E3 ligase function. In agreement with their domain composition, MEX3 proteins were reported to modulate both RNA fate and protein ubiquitination. MEX3 paralogs exhibit an oncofetal expression pattern, they are severely downregulated postnatally, and re-expression is observed in various malignancies. Enforced expression of MEX3 proteins in various cancers correlates with poor prognosis, emphasizing their oncogenic potential. The latter is supported by MEX3A's impact on proliferation, self-renewal as well as migration of tumor cells in vitro and tumor growth in xenograft studies.