A2BAR Antagonism Decreases the Glomerular Expression and Secretion of Chemoattractants for Monocytes and the Pro-Fibrotic M2 Macrophages Polarization during Diabetic Nephropathy.

Some chemoattractants and leukocytes such as M1 and M2 macrophages are known to be involved in the development of glomerulosclerosis during diabetic nephropathy (DN). In the course of diabetes, an altered and defective cellular metabolism leads to the increase in adenosine levels, and thus to changes in the polarity (M1/M2) of macrophages. MRS1754, a selective antagonist of the A2B adenosine receptor (A2BAR), attenuated glomerulosclerosis and decreased macrophage-myofibroblast transition in DN rats. Therefore, we aimed to investigate the effect of MRS1754 on the glomerular expression/secretion of chemoattractants, the intraglomerular infiltration of leukocytes, and macrophage polarity in DN rats. Kidneys/glomeruli of non-diabetic, DN, and MRS1754-treated DN rats were processed for transcriptomic analysis, immunohistopathology, ELISA, and in vitro macrophage migration assays. The transcriptomic analysis identified an upregulation of transcripts and pathways related to the immune system in the glomeruli of DN rats, which was attenuated using MRS1754. The antagonism of the A2BAR decreased glomerular expression/secretion of chemoattractants (CCL2, CCL3, CCL6, and CCL21), the infiltration of macrophages, and their polarization to M2 in DN rats. The in vitro macrophages migration induced by conditioned-medium of DN glomeruli was significantly decreased using neutralizing antibodies against CCL2, CCL3, and CCL21. We concluded that the pharmacological blockade of the A2BAR decreases the transcriptional expression of genes/pathways related to the immune response, protein expression/secretion of chemoattractants, as well as the infiltration of macrophages and their polarization toward the M2 phenotype in the glomeruli of DN rats, suggesting a new mechanism implicated in the antifibrotic effect of MRS1754.

Immune Modulation by Myeloid-Derived Suppressor Cells in Diabetic Kidney Disease.

Diabetic kidney disease (DKD) frequently leads to end-stage renal disease and other life-threatening illnesses. The dysregulation of glomerular cell types, including mesangial cells, endothelial cells, and podocytes, appears to play a vital role in the development of DKD. Myeloid-derived suppressor cells (MDSCs) exhibit immunoregulatory and anti-inflammatory properties through the depletion of L-arginine that is required by T cells, through generation of oxidative stress, interference with T-cell recruitment and viability, proliferation of regulatory T cells, and through the promotion of pro-tumorigenic functions. Under hyperglycemic conditions, mouse mesangial cells reportedly produce higher levels of fibronectin and pro-inflammatory cytokines. Moreover, the number of MDSCs is noticeably decreased, weakening inhibitory immune activities, and creating an inflammatory environment. In diabetic mice, immunotherapy with MDSCs that were induced by a combination of granulocyte-macrophage colony-stimulating factor, interleukin (IL)-1ß, and IL-6, reduced kidney to body weight ratio, fibronectin expression, and fibronectin accumulation in renal glomeruli, thus ameliorating DKD. In conclusion, MDSCs exhibit anti-inflammatory activities that help improve renal fibrosis in diabetic mice. The therapeutic targeting of the proliferative or immunomodulatory pathways of MDSCs may represent an alternative immunotherapeutic strategy for DKD.

Hyperoside Suppresses Renal Inflammation by Regulating Macrophage Polarization in Mice With Type 2 Diabetes Mellitus.

Accumulating evidence reveals that both inflammation and lymphocyte dysfunction play a vital role in the development of diabetic nephropathy (DN). Hyperoside (HPS) or quercetin-3-O-galactoside is an active flavonoid glycoside mainly found in the Chinese herbal medicine Tu-Si-Zi. Although HPS has a variety of pharmacological effects, including anti-oxidative and anti-apoptotic activities as well as podocyte-protective effects, its underlying anti-inflammatory mechanisms remain unclear. Herein, we investigated the therapeutic effects of HPS on murine DN and the potential mechanisms responsible for its efficacy. We used C57BLKS/6J Lepdb/db mice and a high glucose (HG)-induced bone marrow-derived macrophage (BMDM) polarization system to investigate the potentially protective effects of HPS on DN. Our results showed that HPS markedly reduced diabetes-induced albuminuria and glomerular mesangial matrix expansion, accompanied with a significant improvement of fasting blood glucose level, hyperlipidaemia and body weight. Mechanistically, pretreatment with HPS effectively regulated macrophage polarization by shifting proinflammatory M1 macrophages (F4/80+CD11b+CD86+) to anti-inflammatory M2 ones (F4/80+CD11b+CD206+) in vivo and in bone marrow-derived macrophages (BMDMs) in vitro, resulting in the inhibition of renal proinflammatory macrophage infiltration and the reduction in expression of monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor (TNF-α) and inducible nitric oxide synthase (iNOS) while increasing expression of anti-inflammatory cytokine Arg-1 and CD163/CD206 surface molecules. Unexpectedly, pretreatment with HPS suppressed CD4+ T cell proliferation in a coculture model of IL-4-induced M2 macrophages and splenic CD4+ T cells while promoting their differentiation into CD4+IL-4+ Th2 and CD4+Foxp3+ Treg cells. Taken together, we demonstrate that HPS ameliorates murine DN via promoting macrophage polarization from an M1 to M2 phenotype and CD4+ T cell differentiation into Th2 and Treg populations. Our findings may be implicated for the treatment of DN in clinic.

Effects of a CCR2 antagonist on macrophages and Toll-like receptor 9 expression in a mouse model of diabetic nephropathy.

The pathogenesis of diabetic nephropathy (DN) is related to macrophage (Mφ) recruitment to the kidneys, tumor necrosis factor-α (TNF-α) production, and oxidative stress. Toll-like receptor 9 (TLR9) activation is reportedly involved in systemic inflammation, and it exacerbates this condition in metabolic syndrome. Therefore, we hypothesized that TLR9 plays a role in the pathogenesis of DN. Two subsets of kidney Mφs in DN model (db/db) mice were analyzed using flow cytometry to evaluate their distribution and TLR9 expression and function. Mice were administered the CCR2 antagonist INCB3344 for 8 wk; changes in Mφ distribution and function and its therapeutic effects on DN pathology were examined. Bone marrow-derived CD11bhigh (BM-Mφ) and tissue-resident CD11blow Mφs (Res-Mφ) were identified in the mouse kidneys. As DN progressed, the BM-Mφ number, TLR9 expression, and TNF-α production increased significantly. In Res-Mφs, reactive oxygen species (ROS) production and phagocytic activity were enhanced. INCB3344 decreased albuminuria, serum creatinine level, BM-Mφ abundance, TLR9 expression, and TNF-α production by BM-Mφs and ROS production by Res-Mφs. Both increased activation of BM-Mφ via TLR9 and TNF-α production and increased ROS production by Res-Mφs were involved in DN progression. Thus, inactivating Mφs and their TLR9 expression by INCB3344 is a potential therapeutic strategy for DN.NEW & NOTEWORTHY We classified kidney macrophages (Mφs) into bone marrow-derived Mφs (BM-Mφs) expressing high CD11b and tissue-specific resident Mφ (Res-Mφs) expressing low CD11b. In diabetic nephropathy (DN) model mice, Toll-like receptor 9 (TLR9) expression and TNF-α production via TLR9 activation in BM-Mφs and ROS production in Res-Mφs were enhanced. Furthermore, CCR2 antagonist suppressed the kidney infiltration of BM-Mφs and their function and the ROS production by Res-Mφs, with concomitant TLR9 suppression. Our study presents a new therapeutic strategy for DN.

LINC00323 mediates the role of M1 macrophage polarization in diabetic nephropathy through PI3K/AKT signaling pathway.

OBJECTIVE: To explore the effect of LINC00323 on the polarization of M1 macrophages in diabetic nephropathy. To study the effect and biological mechanism of LINC00323 on the occurrence and development of diabetic nephropathy. METHODS: We used clinical samples to analyze the correlation between macrophage polarization and the occurrence and development of diabetic nephropathy. In addition, we used bioinformatics to analyze the key molecules of macrophage polarization. We then verified the key pathways that promote the M1 polarization of macrophages at the level of cell biology. And we verify the effectiveness of treatment against this target in animal experiments. RESULTS: We analyzed in clinical samples that the expression of inflammatory factors (TNF-α and IL-6) increased in patients with diabetic nephropathy. In addition, we found that the expression of M1 marker protein CD86 increased through PCR and western blot analysis. We found a key target (LINC00323) through bioinformatics. The expression of LINC00323 in patients' blood samples is also at a high level. We further explored the mechanism of LINC00323 involved in the polarization of M1 macrophages at the level of cellular molecular biology, and found that it is closely related to the PI3K/AKT signaling pathway. In animal models, we found that inhibiting the expression of LINC00323 can reduce the damage of diabetic nephropathy. CONCLUSION: We found that LINC00323 mediates the polarization of M1 macrophages through the PI3K/AKT signaling pathway. LINC00323 plays an important role in the occurrence and development of diabetic nephropathy.

Diabetic Nephropathy and COVID-19: The Potential Role of Immune Actors.

Nowadays, type II diabetes mellitus, more specifically ensuing diabetic nephropathy, and severe COVID-19 disease are known to be closely associated. The exact mechanisms behind this association are less known. An implication for the angiotensin-converting enzyme 2 remains controversial. Some researchers have started looking into other potential actors, such as neuropilin-1, mitochondrial glutathione, vitamin D, and DPP4. In particular, neuropilin-1 seems to play an important role in the underlying mechanism linking COVID-19 and diabetic nephropathy. We suggest, based on the findings in this review, that its up-regulation in the diabetic kidney facilitates viral entry in this tissue, and that the engagement of both processes leads to a depletion of neuropilin-1, which was demonstrated to be strongly associated with the pathogenesis of DN. More studies are needed to confirm this hypothesis, and research should be directed towards elucidating the potential roles of all these suggested actors and eventually discovering new therapeutic strategies that could reduce the burden of COVID-19 in patients with diabetic nephropathy.

ß3-integrin Leu33Pro gain of function variant does not modulate inflammatory activity in human derived macrophages in diabetes.

Objective: We aimed to investigate the association between the Leu33Pro (rs5918) polymorphism in ß3-integrin with diabetic complications and inflammatory function of macrophages depending on the genotype in subjects with diabetes mellitus. Material and methods: We determined the Leu33Pro polymorphism in 186 diabetic subjects and collected laboratory data. Monocytes from 24 patients were collected for macrophage differentiation to determine the inflammatory activity by treating with different stimulants. Results: We could demonstrate that human derived differentiated macrophages expressed ß3­integrin. Their secretory capacity upon inflammatory stimulation did not reveal any differences depending on the Leu33Pro variant. We found trends for an association of the polymorphism with the presence of diabetic nephropathy (p = 0.071), as well as with creatinine [1.32 mg/dL (1) vs. 0.98 mg/dL (0)] (p = 0.029 in recessive model) and glomerular filtration rate [75.6 ml/min ± 22 vs. 62.3 ml/min ± 25] (p = 0.076 in recessive model) as quantitative markers of kidney function. Conclusion: Despite the expression of ß3­integrin in human macrophages, the Leu33Pro polymorphism in ß3­integrin does not modify the inflammatory response upon stimulation but might play a role in the progression of diabetic nephropathy. Further studies are necessary to substantiate such a hypothesis.

Diabetic Kidney Disease Alters the Transcriptome and Function of Human Adipose-Derived Mesenchymal Stromal Cells but Maintains Immunomodulatory and Paracrine Activities Important for Renal Repair.

Mesenchymal stem/stromal cells (MSCs) facilitate repair in experimental diabetic kidney disease (DKD). However, the hyperglycemic and uremic milieu may diminish regenerative capacity of patient-derived therapy. We hypothesized that DKD reduces human MSC paracrine function. Adipose-derived MSC from 38 participants with DKD and 16 control subjects were assessed for cell surface markers, trilineage differentiation, RNA sequencing (RNA-seq), in vitro function (coculture or conditioned medium experiments with T cells and human kidney cells [HK-2]), secretome profile, and cellular senescence abundance. The direction of association between MSC function and patient characteristics were also tested. RNA-seq analysis identified 353 differentially expressed genes and downregulation of several immunomodulatory genes/pathways in DKD-MSC versus Control-MSC. DKD-MSC phenotype, differentiation, and tube formation capacity were preserved, but migration was reduced. DKD-MSC with and without interferon-γ priming inhibited T-cell proliferation greater than Control-MSC. DKD-MSC medium contained higher levels of anti-inflammatory cytokines (indoleamine 2,3-deoxygenase 1 and prostaglandin-E2) and prorepair factors (hepatocyte growth factor and stromal cell-derived factor 1) but lower IL-6 versus control-MSC medium. DKD-MSC medium protected high glucose plus transforming growth factor-ß-exposed HK-2 cells by reducing apoptotic, fibrotic, and inflammatory marker expression. Few DKD-MSC functions were affected by patient characteristics, including age, sex, BMI, hemoglobin A1c, kidney function, and urine albumin excretion. However, senescence-associated ß-galactosidase activity was lower in DKD-MSC from participants on metformin therapy. Therefore, while DKD altered the transcriptome and migratory function of culture-expanded MSCs, DKD-MSC functionality, trophic factor secretion, and immunomodulatory activities contributing to repair remained intact. These observations support testing of patient-derived MSC therapy and may inform preconditioning regimens in DKD clinical trials.

Association of platelet-to-lymphocyte ratio with kidney clinicopathologic features and renal outcomes in patients with diabetic kidney disease.

BACKGROUND: Growing evidence points to the pivotal role of inflammation in the pathogenesis of diabetic kidney disease (DKD). However, as an inflammation-based prognostic score, the significance of platelet-to-lymphocyte ratio (PLR) in biopsy-proven DKD remains uncertain. Therefore, the current study aimed to evaluate the association of PLR with the clinicopathological features and the progression of DKD. METHODS: In total, 167 patients with biopsy-proven T2DKD were retrospectively recruited. Clinicopathological characteristics were compared according to the tertiles of baseline PLR. Pearson's or Spearman correlations were used to examine the associations between PLR and baseline characteristics. Assessment of the prospective relationship of PLR with the kidney outcomes defined as a doubling of baseline serum creatinine or onset of end stage renal disease (ESRD), were investigated by Kaplan-Meier survival analysis. Moreover, a cubic spline curve was further calculated to explore the significance of PLR in DKD prognosis. On top of that, identification of the risk factors associated with DKD progression was executed by a model of Cox proportional hazards. RESULTS: Median follow-up period was 23.77 months, during which 92 (55.1%) patients confronted DKD progression. Pearson's correlation indicated that urinary protein increased along with PLR rising (r = 0.193, P = 0.012). Kaplan-Meier survival curves revealed a significantly increased probability of event-free survival in the lowest tertile of PLR compared to those in the highest tertile (P = 0.018). A statistical linear correlation between PLR and DKD development was demonstrated by a restricted cubic spline analysis (P for nonlinear = 0.784). In addition, the analyses of multivariate Cox regression indicated that elevated PLR had an association with a greater risk of DKD progression (HR 1.004, 95%CI [1.000-1.008], P = 0.035), which was verified to be an independent risk factor for renal outcomes. CONCLUSIONS: Our findings demonstrated that the PLR was associated with proteinuria and prognosis in DKD patients. It was an independent risk factor for kidney progression in biopsy-proven DKD.

The role of Neuropilin-1 in COVID-19.

Neuropilin-1 (NRP-1), a member of a family of signaling proteins, was shown to serve as an entry factor and potentiate SARS Coronavirus 2 (SARS-CoV-2) infectivity in vitro. This cell surface receptor with its disseminated expression is important in angiogenesis, tumor progression, viral entry, axonal guidance, and immune function. NRP-1 is implicated in several aspects of a SARS-CoV-2 infection including possible spread through the olfactory bulb and into the central nervous system and increased NRP-1 RNA expression in lungs of severe Coronavirus Disease 2019 (COVID-19). Up-regulation of NRP-1 protein in diabetic kidney cells hint at its importance in a population at risk of severe COVID-19. Involvement of NRP-1 in immune function is compelling, given the role of an exaggerated immune response in disease severity and deaths due to COVID-19. NRP-1 has been suggested to be an immune checkpoint of T cell memory. It is unknown whether involvement and up-regulation of NRP-1 in COVID-19 may translate into disease outcome and long-term consequences, including possible immune dysfunction. It is prudent to further research NRP-1 and its possibility of serving as a therapeutic target in SARS-CoV-2 infections. We anticipate that widespread expression, abundance in the respiratory and olfactory epithelium, and the functionalities of NRP-1 factor into the multiple systemic effects of COVID-19 and challenges we face in management of disease and potential long-term sequelae.

MiR-21-5p in macrophage-derived extracellular vesicles affects podocyte pyroptosis in diabetic nephropathy by regulating A20.

OBJECTIVES: Podocyte pyroptosis, characterized by inflammasome activation, plays an important role in inflammation-mediated diabetic nephropathy (DN). Our study aimed to investigate whether miR-21-5p in macrophage-derived extracellular vesicles (EVs) could affect podocyte injury in DN. METHODS: EVs were extracted after the treatment of RAW 264.7 (mouse macrophage line) with high glucose (HG). The podocyte pyroptosis was determined using the flow cytometry and the western blot. After the knockdown of miR-21-5p in HG-induced RAW264.7 cells, we injected the extracted EVs into DN model mice. RESULTS: The level of miR-21-5p was higher in HG-stimulated macrophage-derived EVs than in normal glucose-cultured macrophage-derived EVs. The co-culture of EVs and podocytes promoted reactive oxygen species (ROS) production and activation of inflammatory in MPC5 cells (mouse podocyte line). However, restraint of miR-21-5p in EVs reduced ROS production and inhibit inflammasome activation in MPC5 cells, thereby reducing podocytes injury. Meanwhile, we found that miR-21-5p inhibited the A20 expression through binding with its 3'-untranslated regions in MPC5 cells. Further studies showed that A20 was also involved in the regulation of miR-21-5p of RAW 264.7-derived EVs on MPC5 injury. At the same time, it was also proved in the DN model mice that miR-21-5p in macrophage-derived EVs could regulate podocyte injury. CONCLUSION: MiR-21-5p in macrophage-derived EVs can regulate pyroptosis-mediated podocyte injury by A20 in DN.

Genetic variation in CARD8, a gene coding for an NLRP3 inflammasome-associated protein, alters the genetic risk for diabetic nephropathy in the context of type 2 diabetes mellitus.

BACKGROUND: Approximately one third of type 2 diabetes mellitus (T2DM) cases present with diabetic nephropathy (DN), the leading cause of end-stage renal disease. Inflammation plays an important role in T2DM disease and DN pathogenesis. NLRP3 inflammasomes are complexes that regulate interleukin-1B (IL-1B) and IL-18 secretion, both involved in inflammatory responses. Activation of NLRP3 is associated with DN onset and progression. Here, we explore whether DN is associated with variants in genes encoding key members of the NLRP3 inflammasome pathway. METHODS: Using genome-wide association data, we performed a pilot case-control association study, between 101 DN-T2DM and 185 non-DN-T2DM cases from the Hellenic population across six NLRP3 inflammasome pathway genes. RESULTS: Three common CARD8 variants confer decreased risk for DN, namely rs11665831 (OR = 0.62, p = 0.016), rs11083925 (OR = 0.65, p = 0.021), and rs2043211 (OR = 0.66, p = 0.026), independent of sex or co-inheritance with an IL-1B variant. CONCLUSION: CARD8 acts as an NLRP3, NF-κB and caspase-1 inhibitor; perhaps, alterations in the cross-talk between CARD8, NF-κB, and NLRP3, which could affect the pro-inflammatory environment in T2DM, render diabetic carriers of certain common CARD8 variants potentially less likely to develop T2DM-related pro-inflammatory responses followed by DN. These preliminary, yet novel, observations will require validation in larger cohorts from several ethnic groups.

Conversion of extracellular ATP into adenosine: a master switch in renal health and disease.

ATP and its ultimate degradation product adenosine are potent extracellular signalling molecules that elicit a variety of pathophysiological functions in the kidney through the activation of P2 and P1 purinergic receptors, respectively. Extracellular purines can modulate immune responses, balancing inflammatory processes and immunosuppression; indeed, alterations in extracellular nucleotide and adenosine signalling determine outcomes of inflammation and healing processes. The functional activities of ectonucleotidases such as CD39 and CD73, which hydrolyse pro-inflammatory ATP to generate immunosuppressive adenosine, are therefore pivotal in acute inflammation. Protracted inflammation may result in aberrant adenosinergic signalling, which serves to sustain inflammasome activation and worsen fibrotic reactions. Alterations in the expression of ectonucleotidases on various immune cells, such as regulatory T cells and macrophages, as well as components of the renal vasculature, control purinergic receptor-mediated effects on target tissues within the kidney. The role of CD39 as a rheostat that can have an impact on purinergic signalling in both acute and chronic inflammation is increasingly supported by the literature, as detailed in this Review. Better understanding of these purinergic processes and development of novel drugs targeting these pathways could lead to effective therapies for the management of acute and chronic kidney disease.

Polyclonal immunoglobulin G deposition on the tubular basement membrane in a diabetic nephropathy: A case report.

A 70-year-old Japanese man with diabetes mellitus was referred to our hospital for treatment of renal dysfunction. Renal biopsy revealed that the tubular basement membrane (TBM) showed extreme thickening histologically, and selective polyclonal immunoglobulin G deposition on the thickened TBM, whereas no immunoglobulin deposition was found in the glomeruli in an immunofluorescence study. In electron microscopy, a powdery type of electron dense material, which was similar to that seen in Randall-type monoclonal immunoglobulin deposition disease (MIDD), was observed on the tubular epithelial side of the TBM. However, the present case was differentiated from MIDD, because polyclonal deposition with both kappa and lambda deposition on the TBM was observed. Moreover, there was no noticeable glomerular deposition, which is usually found in cases of MIDD. Anti-TBM disease was also considered as a differential diagnosis, in which polyclonal immunoglobulin deposits selectively on the TBM. However, in the present case, prominent interstitial nephritis was not observed. A similar case with a history of diabetes mellitus has been reported, which was diagnosed as Polyclonal Immunoglobulin G Deposition Disease. No further reports of this case have emerged thereafter; we present this case as the second report supporting this article.

Macrophage Phenotype and Fibrosis in Diabetic Nephropathy.

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease globally. The primary initiating mechanism in DN is hyperglycemia-induced vascular dysfunction, but its progression is due to different pathological mechanisms, including oxidative stress, inflammatory cells infiltration, inflammation and fibrosis. Macrophages (Mφ) accumulation in kidneys correlates strongly with serum creatinine, interstitial myofibroblast accumulation and interstitial fibrosis scores. However, whether or not Mφ polarization is involved in the progression of DN has not been adequately defined. The prevalence of the different phenotypes during the course of DN, the existence of hybrid phenotypes and the plasticity of these cells depending of the environment have led to inconclusive results. In the same sense the role of the different macrophage phenotype in fibrosis associated or not to DN warrants additional investigation into Mφ polarization and its role in fibrosis. Due to the association between fibrosis and the progressive decline of renal function in DN, and the role of the different phenotypes of Mφ in fibrosis, in this review we examine the role of macrophage phenotype control in DN and highlight the potential factors contributing to phenotype change and injury or repair in DN.

Mesenchymal stem cells alleviate rat diabetic nephropathy by suppressing CD103+ DCs-mediated CD8+ T cell responses.

Diabetic nephropathy (DN) as a kind of serious microvascular complication of Diabetes Mellitus (DM) usually causes the end-stage of renal disease (ESRD). Studies have demonstrated that CD103+ dendritic cells (DCs) exhibited a renal pathogenic effect in murine chronic kidney disease (CKD). Mesenchymal stem cells (MSCs) can alleviate DN and suppress the DCs maturation. To explore the role of CD103+ DCs and the potential mechanisms underlying MSCs-mediated protective effects in DN, we used bone marrow MSCs (BM-MSCs) to treat DN rats. MSCs transplantation considerably recovered kidney function and diminished renal injury, fibrosis and the population of renal CD103+ DCs in DN rat. The MSCs-treated DN rats had decreased mRNA expression levels of interleukin (IL)1ß, IL6, tumour necrosis factor alpha (TNF-α), monocyte chemotactic protein 1 (MCP-1) and reduced CD8 T cell infiltration in the kidney. MSCs significantly down-regulated the genes expression of transcription factors (Basic leucine zipper transcriptional factor ATF-like 3, Batf3 and DNA-binding protein inhibitor ID-2, Id2) and FMS-like tyrosine kinase-3 (Flt3) which are necessary for CD103+ DCs development. The protective effect of MSCs may be partly related to their immunosuppression of CD8+ T cell proliferation and activation mediated by CD103+ DCs in the kidney of DN rats.

MiR-770-5p facilitates podocyte apoptosis and inflammation in diabetic nephropathy by targeting TIMP3.

OBJECTIVE: Diabetic nephropathy (DN) is one of the most severe and frequent diabetic complications. MicroRNAs (miRNAs) have been reported to play a vital role in DN pathogenesis. The present study aimed to investigate the molecular mechanism of miR-770-5p in DN. METHODS: Podocyte injury model was established by treating mouse podocytes with high glucose (HG, 33 mM) for 24 h. The levels of miR-770-5p and TIMP3 were examined in kidney tissues and podocytes using quantitative real-time PCR (qRT-PCR). Flow cytometry analysis was applied to detect apoptosis in podocytes. Western blot assay was used to measure the protein levels of B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X (Bax) and tissue inhibitors of metalloproteinase 3 (TIMP3). Enzyme-linked immunosorbent assay (ELISA) was conducted to measure the levels of inflammatory factors. The interaction between miR-770-5p and TIMP3 was determined by MicroT-CDS and luciferase reporter assay. RESULTS: MiR-770-5p was up-regulated and TIMP3 was down-regulated in DN kidney tissues and HG-stimulated podocytes. Depletion of miR-770-5p suppressed cell apoptosis and the release of pro-inflammatory factors in HG-treated podocytes. Additionally, TIMP3 was a target of miR-770-5p in HG-treated podocytes. TIMP3 inhibited cell apoptosis and inflammation in HG-treated podocytes. Moreover, TIMP3 knockdown alleviated the inhibitory effect of miR-770-5p silencing on podocyte apoptosis and inflammatory response. CONCLUSION: Knockdown of miR-770-5p suppressed podocyte apoptosis and inflammatory response by targeting TIMP3 in HG-treated podocytes, indicating that miR-770-5p may be a potential therapeutic target for DN therapy.

TNF-α pathway and T-cell immunity are activated early during the development of diabetic nephropathy in Type II Diabetes Mellitus.

Aim of the present study was to investigate the possible involvement of TNF-α signaling pathway and T-lymphocyte activation in DN. Eighty-two diabetic patients [39 male, age 69.5(56-78)years] were divided into three groups, according to Albumin/Creatinine ratio (ACR) levels, Group I (ACR < 30 µg/mg), Group II (ACR 30-300 µg/mg), Group III (ACR > 300 µg/mg). Urinary Tumor Necrosis Factor-α (TNF-α), and serum TNF-α, ΤNF-receptor 1 (TNFR1), TNFR2, B7-1, CD28, Cytoxic T-Lymphocyte-Associated protein-4 (CTLA4), were estimated. There were significant differences between Groups I, II, III regarding the concentration of urinary TNF-α (p < .001), serum TNFR1 (p < .001), serum TNFR2(p < .001), CTLA4 (p < .001) and CD28(p = .034). In multivariate analysis, independent parameters correlated with ACR were serum TNFR1 (p = .003), TNFR2 (p = .012) and urinary TNF-α (p = .015) levels. There was a significant correlation between markers of T-cell activation and TNF-α signaling pathway activation. Activation of TNF-α signaling pathway and T-lymphocytes seem to synergize and participate in the development of DN in type II DM.

Protective effect of ginsenoside Rg5 against kidney injury via inhibition of NLRP3 inflammasome activation and the MAPK signaling pathway in high-fat diet/streptozotocin-induced diabetic mice.

Diabetic nephropathy (DN) is a common and serious complication of diabetes and causes kidney failure. Ginsenoside Rg5 (Rg5) is an important monomer in the main protopanaxadiol component of black ginseng. Rg5 has exhibited some beneficial biological effects, such as anti-cancer, neuroprotection, and anti-depression, but the effect of Rg5 on DN and its potential mechanism remains unclear. The aim of this study is to investigate the effect of Rg5 on kidney injury of C57BL/6 diabetic mice induced by high-fat diet and streptozotocin. After treatment with different concentration of Rg5 (30 and 60 mg kg-1·d-1) for 6 consecutive weeks, the fasting blood glucose, insulin levels, serum creatinine, serum urea, and serum UA in Rg5-treated DN mice were significantly reduced, while the renal histopathology was remarkably improved, compared with untreated DN mice. Moreover, ROS production, oxidative stress markers (MDA, SOD, and GSH-PX), Nox4 and TXNIP expressions of kidney in DN mice were significantly reduced after Rg5 treatment. Additionally, the expression levels of the NLRP3 inflammasome (NLRP3, ASC, and Caspase-1) and the inflammatory cytokines IL-1ß and IL-18 were significantly inhibited, and the expression of NF-kB and the phosphorylation of p38 MAPK were also decreased with Rg5 treatment compared with no treatment in DN mice. Together, our results indicate that Rg5 attenuated renal injury in diabetic mice by inhibiting oxidative stress and NLRP3 inflammasome activation to reduce inflammatory responses, indicating that Rg5 is a potential compound to prevent or control diabetic renal injury.

MicroRNA-544 attenuates diabetic renal injury via suppressing glomerulosclerosis and inflammation by targeting FASN.

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease. Accumulating evidence shows that microRNAs play important roles in diabetic kidney. However, the potential role of MicroRNA-544 (miR-544) in DN remains unclear. In this study, we explored the role of miR-544 on inflammation and fibrosis in diabetic kidney using db/db mice. Renal expression of miR-544 was decreased in mice, companied by increased the expression of FASN. The dual luciferase assay confirmed FASN as a direct target of miR-544. Over-expression of miR-544 significantly ameliorated renal injury, mesangial matrix and renal fibrosis. In addition, over-expression of miR-544 significantly attenuated inflammatory cells infiltration and IL-1, IL-6, TNF- and iNOS production in DN. Furthermore, miR-544 over-expression inhibited the activation of NF-kB signal pathway in DN. In conclusion, our finding demonstrated that miR-544 attenuates diabetic renal injury via suppressing glomerulosclerosis and inflammation by targeting FASN, suggesting that miR-544 might have therapeutic potential for the treatment of DN.