Fuxin Granules ameliorate diabetic nephropathy in db/db mice through TGF-β1/Smad and VEGF/VEGFR2 signaling pathways

SB-525334 ameliorates renal injury in diabetic kidney disease mouse model via suppressing inflammation

BACKGROUND

Diabetic kidney disease (DKD; also known as diabetic nephropathy) is a typical complication of diabetes mellitus characterised by renal injury due to disturbances in glucose metabolism, in which renal tubular damage caused by chronic inflammation has been shown to be closely associated with the development of end-stage renal disease (ESRD). However, there are insufficient effective therapeutic agents to halt the progression of DKD.

METHODS

In the present study, we screened differential gene expression profiles associated with DKD by mining the GEO database through differential and enrichment analyses. Furthermore, systemic in vivo and in vitro experiments were designed to explore the mechanism through which the potential therapeutic agent SB-525334 improves DKD.

RESULTS

SB-525334 ameliorated DKD-induced kidney injury by regulating inflammatory cytokines (TGF-β1, IL-6, IL-10) as well as promoting the translation of M1 (iNOS) macrophage to M2 (CD206) macrophage. In addition, SB-525334 ameliorates kidney injury caused by DKD through inhibiting inflammation through regulating the expression of key proteins in the TGF-β1 /JNK and TGF-β1 /Smad signaling pathways. For studies in vitro, inflammation induced by LPS in vitro was inhibited significantly after the administration of SB-525334 through down-regulating pro-inflammatory cytokines, promoting macrophage conversion from M1 to M2, and inhibiting the activation of TGF-β1 /JNK and TGF-β1 /Smad pathways.

CONCLUSIONS

These results highlight that the target compound SB-525334 could serve as a novel potential therapeutic agent and ameliorate DKD in an inflammation-inhibiting manner.

Therapeutic Effect of Desmodium caudatum Extracts on Alleviating Diabetic Nephropathy Mice

Desmodium caudatum extracts (DCE) were investigated for their potential therapeutic effects on diabetic nephropathy (DN). In our study, the high-fat diet (HFD) / streptozotocin (STZ)-induced DN model in C57BL/6 mice was treated with 100 mg/kg, 200 mg/kg DCE. The results showed that DCE decreased biochemical parameters and proteinuria levels. The kidney sections staining indicated that DCE treatment recovered glomerular atrophy and alleviated lipid droplets in the glomerular. Additionally, DCE inhibited lipid and glycogen accumulation down-regulated the expression of sterol regulatory element-binding protein 1 (SREBP1) and fatty acid synthase (FAS) proteins. DCE also reduced collagenous fibrous tissue and the expression of transforming growth factor-β1 (TGF-β1) and alpha-smooth muscle actin (α-SMA) through Masson's trichrome staining and immunohistochemical analysis. We found that DCE alleviated hydroxyproline content, and epithelial-mesenchymal transition (EMT). Besides, the results shown that DCE enhanced the antioxidant enzymes to mitigate fibrosis by reducing oxidative stress. In conclusion, our study provided evidence of the protective effect of DCE which down-regulated hyperglycemia, hyperlipidemia and inhibition of TGF-β1 and EMT pathway but elevated antioxidant, suggesting its therapeutic implication for DN.

Rutaecarpine protects podocytes in diabetic kidney disease by targeting VEGFR2/NLRP3-mediated pyroptosis

OBJECTIVE

Diabetic kidney disease (DKD) is the most common cause of the end-stage renal disease, which has limited treatment options. Rutaecarpine has anti-inflammatory effects, however, it has not been studied in DKD. Pyroptosis is a newly discovered mode of podocyte death related to inflammation. This study aimed to explore whether Rutaecarpine can ameliorate DKD and to clarify its possible mechanism.

METHODS

In this study, we investigated the effects of Rutaecarpine on DKD using diabetic mice model (db/db mice) and high glucose (HG)-stimulated mouse podocyte clone 5 (MPC5) cells. Quantitative reverse transcription polymerase chain reaction and western blot were performed to detect the related gene and protein levels. We applied pharmacological prediction, co-immunoprecipitation assay, cellular thermal shift assay, surface plasmon resonance to find the target and pathway of the substances. Gene knockdown experiments confirmed this view in HG-stimulated MPC5 cells.

RESULTS

Rutaecarpine significantly reduced proteinuria, histopathological damage, and pyroptosis of podocytes in a dose-dependent manner in db/db mice. Rutaecarpine also protected high glucose induced MPC5 injury in vitro experiments. Mechanistically, Rutaecarpine can inhibit pyroptosis in HG-stimulated MPC5 by reducing the expression of VEGFR2. VEGFR2 is a target of Rutaecarpine in MPC5 cells and directly binds to the pyroptosis initiation signal, NLRP3. VEGFR2-knockdown disrupted the beneficial effects of Rutaecarpine in HG-stimulated MPC5 cells.

CONCLUSION

Rutaecarpine inhibits renal inflammation and pyroptosis through VEGFR2/NLRP3 pathway, thereby alleviating glomerular podocyte injury. These findings highlight the potential of Rutaecarpine as a novel drug for DKD treatment.

Traditional Chinese medicine for the treatment of immune-related nephropathy: A review

Immune-related nephropathy (IRN) refers to immune-response-mediated glomerulonephritis and is the main cause of end-stage renal failure. The pathogenesis of IRN is not fully understood; therefore, treatment is challenging. Traditional Chinese medicines (TCMs) have potent clinical effects in the treatment of the IRN conditions immunoglobulin A nephropathy, lupus nephropathy, and diabetic nephropathy. The underlying mechanisms mainly include its inhibition of inflammation; improvements to renal interstitial fibrosis, oxidative stress, autophagy, apoptosis; and regulation of immunity. In this review, we summarize the clinical symptoms of the three IRN subtypes and the use of TCM prescriptions, herbs, and bioactive compounds in treating IRN, as well as the potential mechanisms, intending to provide a reference for the future study of TCM as IRN treatments.

Ginsenoside Rh2 enhances immune surveillance of natural killer (NK) cells via inhibition of ERp5 in breast cancer

BACKGROUND

One critical component of the immune system that prevents breast cancer cells from forming distant metastasis is natural killer (NK) cells participating in immune responses to tumors. Ginsenoside Rh2 (GRh2) as one of the major active ingredients of ginseng has been employed in treatment of cancers, but the function of GRh2 in modulating the development of breast cancer remains elusive.

PURPOSE

This study was to dissect the effect of GRh2 against breast cancer and its potential mechanisms associated with NK cells, both in vitro and in vivo.

METHODS

MDA-MB-231 and 4T1 cells were used to establish in situ and hematogenous mouse models. MDA-MB-231 and MCF-7 were respectively co-cultured with NK92MI cells or primary NK cells in vitro. Anti-tumor efficacy of GRh2 was verified by immunohistochemistry (IHC), Cell Counting Kit-8 (CCK8), high resolution micro-computed tomography (micro-CT) scanning of lungs and hematoxylin and eosin (H&E) staining. Lactate dehydrogenase (LDH) cytotoxicity assay, flow cytometry, in vivo depletion of NK cells, enzyme-linked immunosorbent assay (ELISA), western blot, quantitative reverse transcription polymerase chain reaction (qRT-PCR), immunofluorescence and cell transfection were performed for investigating the anti-tumor mechanisms of GRh2. Molecular docking, microscale thermophoresis (MST) and cellular thermal shift assay (CETSA) were employed to determine the binding between endoplasmic reticulum protein 5 (ERp5) and GRh2.

RESULTS

We demonstrated that GRh2 exerted prominent impacts on retarding the growth and metastasis of breast cancer through boosting the cytotoxic function of NK cells, as validated by the elevated release of perforin, granzyme B and interferon-γ (IFN-γ). Mechanistical studies revealed that GRh2 was capable of diminishing the expression of ERp5 and GRh2 directly bound to ERp5 in MDA-MB-231 cells as well as on a recombinant protein level. GRh2 prevented the formation of soluble MICA (sMICA) and upregulated the expression level of MICA in vivo and in vitro. Importantly, the reduced lung metastasis of breast cancer by GRh2 was almost abolished upon the depletion of NK cells. Moreover, GRh2 was able to insert into the binding pocket of ERp5 directly.

CONCLUSION

We firstly demonstrated that GRh2 played a pivotal role in augmenting NK cell activity by virtue of modulating the NKG2D-MICA signaling axis via directly binding to ERp5, and may be further optimized to a therapeutic agent for the treatment of breast cancer.

Identification and validation of aging-related gene signatures and their immune landscape in diabetic nephropathy

Background

Aging and immune infiltration have essential role in the physiopathological mechanisms of diabetic nephropathy (DN), but their relationship has not been systematically elucidated. We identified aging-related characteristic genes in DN and explored their immune landscape.

Methods

Four datasets from the Gene Expression Omnibus (GEO) database were screened for exploration and validation. Functional and pathway analysis was performed using Gene Set Enrichment Analysis (GSEA). Characteristic genes were obtained using a combination of Random Forest (RF) and Support Vector Machine Recursive Feature Elimination (SVM-RFE) algorithm. We evaluated and validated the diagnostic performance of the characteristic genes using receiver operating characteristic (ROC) curve, and the expression pattern of the characteristic genes was evaluated and validated. Single-Sample Gene Set Enrichment Analysis (ssGSEA) was adopted to assess immune cell infiltration in samples. Based on the TarBase database and the JASPAR repository, potential microRNAs and transcription factors were predicted to further elucidate the molecular regulatory mechanisms of the characteristic genes.

Results

A total of 14 differentially expressed genes related to aging were obtained, of which 10 were up-regulated and 4 were down-regulated. Models were constructed by the RF and SVM-RFE algorithms, contracted to three signature genes: EGF-containing fibulin-like extracellular matrix (EFEMP1), Growth hormone receptor (GHR), and Vascular endothelial growth factor A (VEGFA). The three genes showed good efficacy in three tested cohorts and consistent expression patterns in the glomerular test cohorts. Most immune cells were more infiltrated in the DN samples compared to the controls, and there was a negative correlation between the characteristic genes and most immune cell infiltration. 24 microRNAs were involved in the transcriptional regulation of multiple genes simultaneously, and Endothelial transcription factor GATA-2 (GATA2) had a potential regulatory effect on both GHR and VEGFA.

Conclusion

We identified a novel aging-related signature allowing assessment of diagnosis for DN patients, and further can be used to predict immune infiltration sensitivity.

Baicalin Exerts a Protective Effect in Diabetic Nephropathy by Repressing Inflammation and Oxidative Stress Through the SphK1/S1P/NF-κB Signaling Pathway

Background

Inflammation and oxidative stress contribute to the development of diabetic nephropathy (DN). Baicalin (BA) shows renal protection against DN through its anti-inflammatory and anti-oxidant properties. However, the molecular mechanism by which BA exerts the therapeutic effects on DN remains to be investigated.

Methods

The db/db mice and high glucose (HG)-induced HK-2 cells were used as the in vivo and in vitro model of DN, respectively. The effects of BA were assessed by detecting the related blood and urine biochemical parameters, kidney histopathology, inflammatory cytokine production, oxidative stress indicators, and apoptosis. Cell viability and apoptosis were detected by CCK-8 assay and TUNEL assay, respectively. Related protein levels were measured by an immunoblotting method.

Results

In db/db model mice, BA reduced serum glucose concentration, decreased blood lipid levels, ameliorated kidney functions, and decreased histopathological changes in kidney tissues. BA also alleviated oxidative stress and inflammation in db/db mice. In addition, BA blocked the activation of sphingosine kinases type 1/sphingosine 1-phosphate (SphK1/S1P)/NF-κB pathway in db/db mice. In HK-2 cells, BA hindered HG-induced apoptosis, oxidative stress and inflammation, while overexpression of SphK1 or S1P could reverse these effects. BA alleviated HG-induced apoptosis, oxidative stress and inflammation in HK-2 cells through the S1P/NF-κB pathway. Furthermore, BA blocked the NF-κB signaling by diminishing p65 nuclear translocation via the SphK1/S1P pathway.

Conclusion

Our study strongly suggests that BA protects against DN via ameliorating inflammation, oxidative stress and apoptosis through the SphK1/S1P/NF-κB pathway. This study provides a novel insight into the therapeutic effects of BA in DN.

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.

NLRP3-mediated pyroptosis in diabetic nephropathy

Diabetic nephropathy (DN) is the main cause of end-stage renal disease (ESRD), which is characterized by a series of abnormal changes such as glomerulosclerosis, podocyte loss, renal tubular atrophy and excessive deposition of extracellular matrix. Simultaneously, the occurrence of inflammatory reaction can promote the aggravation of DN-induced kidney injury. The most important processes in the canonical inflammasome pathway are inflammasome activation and membrane pore formation mediated by gasdermin family. Converging studies shows that pyroptosis can occur in renal intrinsic cells and participate in the development of DN, and its activation mechanism involves a variety of signaling pathways. Meanwhile, the activation of the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome can not only lead to the occurrence of inflammatory response, but also induce pyroptosis. In addition, a number of drugs targeting pyroptosis-associated proteins have been shown to have potential for treating DN. Consequently, the pathogenesis of pyroptosis and several possible activation pathways of NLRP3 inflammasome were reviewed, and the potential drugs used to treat pyroptosis in DN were summarized in this review. Although relevant studies are still not thorough and comprehensive, these findings still have certain reference value for the understanding, treatment and prognosis of DN.

Therapeutic effect and mechanism of combination therapy with ursolic acid and insulin on diabetic nephropathy in a type I diabetic rat model

This work aims to investigate the therapeutic effect of ursolic acid (UA) plus insulin (In) on diabetic nephropathy (DN) in streptozotocin (STZ)-induced T1DM rats. The experimental groups and operational details are as follows: A total of thirty-two SD rats were divided into four groups: the DN model group (DN, n = 8), DN + In treatment group (DN + In, n = 8), DN + In + UA administration group (DN + In + UA, n = 8), and negative control group (control, n = 8). After 8 weeks, changes in renal function indices and pathological damage were assessed. Additionally, oxidative stress-, apoptosis-, and fibrosis-related proteins in kidney tissue were measured. Compared with the control group, the vehicle group showed higher levels of creatine, blood urea nitrogen, urinary protein, apoptosis, and lipid peroxidation; lower superoxide dismutase levels; more severe levels of pathological kidney damage and renal fibrosis; and a deepened degree of EMT and EndMT. Better outcomes were achieved with the combined treatment than with insulin-only treatment. The improvement of TGF-β1, phosphorylated p38 MAPK, FGFR1, SIRT3 and DPP-4 expression levels in renal tissues after combination therapy was greater than that after insulin-only treatment. This study shows that the combination of insulin and UA significantly improved the pathological changes in the renal tissue of T1DM rats, and the underlying mechanism may be related to improving apoptosis and oxidative stress by regulating p38 MAPK, SIRT3, DPP-4 and FGFR1 levels, thereby blocking TGF-β signaling pathway activation and inhibiting EMT and EndMT processes.

Therapeutic potential of traditional Chinese medicine for vascular endothelial growth factor

Vascular endothelial growth factor (VEGF) is the main regulator of physiological angiogenesis during embryonic development, bone growth, and reproductive function, and it also participates in a series of pathological changes. Traditional Chinese medicine (TCM), with a history of more than 2000 years, has been widely used in clinical practice, while the exploration of its mechanisms has only begun. This review summarizes the research of recent years on the influence of TCM on VEGF. It is found that many Chinese medicines and recipes have a regulatory effect on VEGF, indicating that Chinese medicine has broad prospects as a complementary and alternative therapy, providing new treatment ideas for clinical applications and the theoretical basis for research on the mechanisms of TCM.

β-Amyrin ameliorates diabetic nephropathy in mice and regulates the miR-181b-5p/HMGB2 axis in high glucose-stimulated HK-2 cells

Diabetic nephropathy (DN) is a diabetic complication that can cause renal failure. β-amyrin has been identified to possess anti-diabetic property. This study was designed to evaluate the potential role of β-amyrin in DN and its underlying mechanism. Streptozotocin-induced diabetic mice were used as the in vivo model, and high glucose (HG)-stimulated human proximal tubular HK-2 cells were utilized as the in vitro model. Renal histological changes in mice were assessed by hematoxylin-eosin and periodic acid-Schiff staining. HK-2 cell viability and apoptosis were detected by Cell Counting Kit-8 assay and flow cytometry analysis, respectively. β-amyrin was found to ameliorate kidney injury in DN mice and suppressed inflammatory response as well as apoptosis of HG-stimulated HK-2 cells. miR-181-5p expression in murine renal tissues and HK-2 cells was detected by in situ hybridization (ISH) and fluorescence in situ hybridization (FISH). MiR-181b-5p, a previously identified target for diabetic kidney disease, was downregulated in renal tissues and HG stimulated HK-2 cells, and β-amyrin induced the upregulation of miR-181b-5p. Binding relationship between miR-181b-5p and high mobility group box 2 (HMGB2) was confirmed by luciferase reporter assay. MiR-181b-5p bound to 3' untranslated region of HMGB2 to suppress its expression. As shown by immunohistochemical staining and immunofluorescence staining, HMGB2 was upregulated in the in vivo and in vitro models of DN, and β-amyrin induced the downregulation of HMGB2. Moreover, HMGB2 overexpression neutralized the suppressive effects of miR-181b-5p elevation on the inflammatory response and apoptosis of HG-treated HK-2 cells. Overall, β-amyrin ameliorates DN in mice and suppresses inflammatory response and apoptosis of HG-stimulated HK-2 cells via the miR-181b-5p/HMGB2 axis.

Sacubitril/Valsartan Improves Progression of Early Diabetic Nephropathy in Rats Through Inhibition of NLRP3 Inflammasome Pathway

PURPOSE

Diabetic nephropathy (DN), a global disease, is the leading cause of end-stage renal disease. There is a lack of specific treatment for this disease, and early intervention in disease progression is essential. In this paper, we used a rat model of early diabetic nephropathy to explore the therapeutic mechanism of sacubitril/valsartan in rats with early diabetic nephropathy.

MATERIALS AND METHODS

Rats were grouped into 1 normal group; 2. Model group (DN group): STZ (45 mg/kg/d) induced early diabetic nephropathy rats; 3. Sac group: DN rats + Sac group (orally, 60 mg/kg/d) for 6 weeks. After 6 weeks, the levels of serum albumin (ALB), glucose (GLU), creatinine (Cr), urea nitrogen (BUN) and 24-h urinary protein excretion were measured. In renal tissue homogenates, NLRP3 inflammasome, proinflammatory factors IL1-β and TNF-α, oxidative stress MDA and pro-fibrotic cytokine TGF-β1 were performed. Histological analysis of kidneys by hematoxylin and eosin (HE), PAS and Masson trichrome staining.

RESULTS

1. Sacubitril/valsartan (Sac) significantly improved renal hypertrophy, proteinuria and serum albumin levels in rats with early diabetic nephropathy (P < 0.001), and decreased GLU, Scr (P<0.001), and BUN levels (P < 0.01).2. Light microscopy of renal tissues showed glomerular hypertrophy and interstitial inflammatory cell infiltration, and mean glomerular area (MGA) and mean glomerular volume (MGV) were crucially increased in early diabetic nephropathy (P < 0.001), and the Sac group showed reduced renal pathology and improved MGA and MGV (P < 0.001).3. Kidney tissue homogenate levels of NLRP3, Caspase-1, IL1-β, TNF-α, MDA and TGF-β1 were critically, increased in DN rats (P < 0.001), and SOD was significantly decreased. All these indicators above were improved after treatment (P < 0.0001).

CONCLUSION

Nlrp3-inflammasome promote progression of diabetic nephropathy through inflammation, fibrosis and oxidative stress; sacubitril/valsartan ameliorated early diabetes-induced renal damage by inhibiting NLRP3 pathway activation.

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.