Store Operated Calcium Entry Suppressed TGF-β1/SMAD3 Signaling Pathway in Glomerular Mesangial Cells

Our previous study demonstrated that the abundance of extracellular matrix proteins was suppressed by store-operated Ca^(2+) entry (SOCE) in mesangial cells (MCs). The present study was conducted to investigate the underlying mechanism focused on the transforming growth factor-β1 (TGF-β1)/Smad3 pathway, a critical pathway for ECM expansion in diabetic kidneys. We hypothesized that SOCE suppressed ECM protein expression by inhibiting this pathway in MCs. In cultured human MCs, we observed that TGF-β1 (5 ng/ml for 15 h) significantly increased Smad3 phosphorylation, as evaluated by immunoblot. However, this response was markedly inhibited by thapsigargin (1 µM), a classical activator of store-operated Ca^(2+) channels. Consistently, both immunocytochemistry and immunoblot showed that TGF-β1 significantly increased nuclear translocation of Smad3, which was prevented by pretreatment with thapsigargin. Importantly, the thapsigargin effect was reversed by lanthanum (La^(3+); 5 µM) and GSK-7975A (10 µM), both of which are selective blockers of store-operated Ca^(2+) channels. Furthermore, knockdown of Orai1, the pore-forming subunit of the store-operated Ca^(2+) channels, significantly augmented TGF-β1-induced Smad3 phosphorylation. Overexpression of Orai1 augmented the inhibitory effect of thapsigargin on TGF-β1-induced phosphorylation of Smad3. In agreement with the data from cultured MCs, in vivo knockdown of Orai1 specific to MCs using a targeted nanoparticle small interfering RNA delivery system resulted in a marked increase in abundance of phosphorylated Smad3 and in nuclear translocation of Smad3 in the glomerulus of mice. Taken together, our results indicate that SOCE in MCs negatively regulates the TGF-β1/Smad3 signaling pathway

Uncovering the Properties of Energy-Weighted Conformation Space Networks with a Hydrophobic-Hydrophilic Model

The conformation spaces generated by short hydrophobic-hydrophilic (HP) lattice chains are mapped to conformation space networks (CSNs). The vertices (nodes) of the network are the conformations and the links are the transitions between them. It has been found that these networks have “small-world” properties without considering the interaction energy of the monomers in the chain, i. e. the hydrophobic or hydrophilic amino acids inside the chain. When the weight based on the interaction energy of the monomers in the chain is added to the CSNs, it is found that the weighted networks show the “scale-free” characteristic. In addition, it reveals that there is a connection between the scale-free property of the weighted CSN and the folding dynamics of the chain by investigating the relationship between the scale-free structure of the weighted CSN and the noted parameter Z score. Moreover, the modular (community) structure of weighted CSNs is also studied. These results are helpful to understand the topological properties of the CSN and the underlying free-energy landscapes

Increased glomerular filtration rate and impaired contractile function of mesangial cells in TRPC6 knockout mice

The present study was conducted to determine if TRPC6 regulates glomerular filtration rate (GFR) and the contractile function of glomerular mesangial cells (MCs). GFR was assessed in conscious TRPC6 wild type and knockout mice, and in anesthetized rats with and without in vivo knockdown of TRPC6 in kidneys. We found that GFR was significantly greater, and serum creatinine level was significantly lower in TRPC6 deficient mice. Consistently, local knockdown of TRPC6 in kidney using TRPC6 specific shRNA construct significantly attenuated Ang II-induced GFR decline in rats. Furthermore, Ang II-stimulated contraction and Ca2+ entry were significantly suppressed in primary MCs isolated from TRPC6 deficient mice, and the Ca2+ response could be rescued by re-introducing TRPC6. Moreover, inhibition of reverse mode of Na+-Ca2+ exchange by KB-R7943 significantly reduced Ca2+ entry response in TRPC6-expressing, but not in TRPC6-knocked down MCs. Ca2+ entry response was also significantly attenuated in Na+ free solution. Single knockdown of TRPC6 and TRPC1 resulted in a comparable suppression on Ca2+ entry with double knockdown of both. These results suggest that TRPC6 may regulate GFR by modulating MC contractile function through multiple Ca2+ signaling pathways.Fil: Li, Weizu. Anhui Medical University; ChinaFil: Ding, Yanfeng. University of North Texas; Estados UnidosFil: Smedley, Crystal. University of North Texas; Estados UnidosFil: Wang, Yanxia. University of North Texas; Estados UnidosFil: Chaudhari, Sarika. University of North Texas; Estados UnidosFil: Birnbaumer, Lutz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. National Institutes of Health; Estados UnidosFil: Ma, Rong. University of North Texas; Estados Unido

Ginsenoside Rg1 treatment alleviates renal fibrosis by inhibiting the NOX4–MAPK pathway in T2DM mice

AbstractDiabetic kidney disease (DKD) is a severe complication of type 2 diabetes mellitus (T2DM). However, the pathogenesis of DKD remains unclear, and effective treatment strategies are still lacking. Ginsenoside Rg1 (Rg1) has been reported to improve DKD, but the mechanism is unclear. NADPH oxidase 4 (NOX4) is an essential reactive oxygen species (ROS) source in the kidney. The mitogen-activated protein kinase (MAPK) signaling may exacerbate renal fibrosis. Therefore, we hypothesized that Rg1 might alleviate renal injury and fibrosis by inhibiting NOX4 and MAPK signaling in T2DM-induced DKD. We found that Rg1 significantly improves lipid deposition, fibrosis, and ROS production and reduces NOX4, p22phox, p47phox, p-ERK, p-JNK, and p-P38 MAPK expressions in the T2DM mice kidneys. We also found that the high-fat diet treatment in mice and the palmitate (PA) and PA + HG (high glucose) exposure in human mesangial cells could significantly induce lipid deposition, ROS production, fibrosis, and the activation of NOX4–MAPK signaling. The results suggest that high lipid and glucose may play a significant role in DKD progression, while Rg1 may attenuate renal fibrosis by inhibiting NOX4–MAPK signaling

Chronic glucocorticoid exposure activates BK-NLRP1 signal involving in hippocampal neuron damage

Abstract Background Neuroinflammation mediated by NLRP1 (nucleotide-binding oligomerization domain (NOD)-like receptor protein 1) inflammasome plays an important role in many neurological diseases such as Parkinson’s disease (PD) and Alzheimer’s disease (AD). Our previous studies showed that chronic glucocorticoid (GC) exposure increased brain inflammation via NLRP1 inflammasome and induce neurodegeneration. However, little is known about the mechanism of chronic GC exposure on NLRP1 inflammasome activation in hippocampal neurons. Methods Hippocampal neurons damage was assessed by LDH kit and Hoechst 33258 staining. The expression of microtubule-associated protein 2 (MAP2), inflammasome complex protein (NLRP1, ASC and caspase-1), inflammatory cytokines (IL-1β), and large-conductance Ca2+ and voltage-activated K+ channel (BK channels) protein was detected by Western blot. The inflammatory cytokines (IL-1β and IL-18) were examined by ELISA kit. The mRNA levels of NLRP1, IL-1β, and BK were detected by real-time PCR. BK channel currents were recorded by whole-cell patch-clamp technology. Measurement of [K+]i was performed by ion-selective electrode (ISE) technology. Results Chronic dexamethasone (DEX) treatment significantly increased LDH release and neuronal apoptosis and decreased expression of MAP2. The mechanistic studies revealed that chronic DEX exposure significantly increased the expression of NLRP1, ASC, caspase-1, IL-1β, L-18, and BK protein and NLRP1, IL-1β and BK mRNA levels in hippocampal neurons. Further studies showed that DEX exposure results in the increase of BK channel currents, with the subsequent K+ efflux and a low concentration of intracellular K+, which involved in activation of NLRP1 inflammasome. Moreover, these effects of chronic DEX exposure could be blocked by specific BK channel inhibitor iberiotoxin (IbTx). Conclusion Our findings suggest that chronic GC exposure may increase neuroinflammation via activation of BK-NLRP1 signal pathway and promote hippocampal neurons damage, which may be involved in the development and progression of AD

The variations of Endophilin A2-FoxO3a-autophagy signal in AngⅡ-induced dopaminergic neuron injury mouse model and By Biochanin A

Biochanin A is a natural plant estrogen, with various biological activities such as anti-apoptosis, anti-oxidation and suppression of inflammatory. In this study, we investigated the protective effects of biochanin A on AngⅡ-induced dopaminergic neurons damage in vivo and molecular mechanisms. Spontaneous activity and motor ability of mice among groups was detected by open-field test and swim-test. The expression of TH, LC3BⅡ/LC3BⅠ, Beclin-1, P62, p-FoxO3a / FoxO3a, FoxO3 and Endophilin A2 were determined by western blot and immunohistochemistry or immunofluorescence staining. Our results showed that AngⅡ treatment significantly increased the behavioral dysfunction of mice and DA neurons damage. Meanwhile, AngⅡ treatment increased the expression of LC3BⅡ/LC3BⅠ, Beclin-1, P62 and FoxO3a and decreased the expression of Endophilin A2 and p-FoxO3a / FoxO3a, however, biochanin A treatment alleviate these changes. In summary, these results suggest that biochanin A exerts protective effects on AngⅡ-induced mouse model may be related to regulating Endophilin A2, FoxO3a and autophagy-related proteins. However, the specific mechanism is not yet clear and needs further study.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

The stability and bioavailability of curcumin loaded α-lactalbumin nanocarriers formulated in functional dairy drink

There is a high demand for the development of functional foods formulated with health-promoting carotenoids. Curcumin (Cur) is one of the most promising carotenoids, but its application in functional foods especially drinks is limited due to its poor water solubility, low stability and bioavailability. Nanocarriers have shown great potential to solve these problems. In this work, Cur was loaded into nanocarriers made of self-assembly of partially hydrolyzing α-lactalbumin (α-lac). Cur functional dairy drinks were developed by adding Cur-loaded nanocarriers (nanocarriers (Cur)) into dairy drinks, and their colloidal stability and bioavailability were evaluated. The results showed that Cur exhibited intestine-responsive release behavior due to the unique nanospheres micellar structure that the hydrophobic cutting sites were buried in the core and not easily accessible to pepsin. In addition, the α-lac nanocarriers improved the stability of Cur against ultraviolet light. Furthermore, static and accelerated stability experiments showed that nanocarriers (Cur) dairy drinks possessed excellent colloidal stability. According to the sensory evaluation, the addition of nanocarriers (Cur) to dairy drinks significantly improved the perception score of stability and overall assessment. Moreover, nanocarriers (Cur) dairy drinks showed the highest Cur bioavailability. Therefore, the embedding via α-lac nanocarriers is feasible for applying Cur to functional dairy drinks and has broad prospects in the food industry

Phosphoethanolamine cytidylyltransferase ameliorates mitochondrial function and apoptosis in hepatocytes in T2DM in vitro

Liver function indicators are often impaired in patients with type 2 diabetes mellitus (T2DM), who present higher concentrations of aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyl transferase than individuals without diabetes. However, the mechanism of liver injury in patients with T2DM has not been clearly elucidated. In this study, we performed a lipidomics analysis on the liver of T2DM mice, and we found that phosphatidylethanolamine (PE) levels were low in T2DM, along with an increase in diglyceride, which may be due to a decrease in the levels of phosphoethanolamine cytidylyltransferase (Pcyt2), thus likely affecting the de novo synthesis of PE. The phosphatidylserine decarboxylase pathway did not change significantly in the T2DM model, although both pathways are critical sources of PE. Supplementation with CDP-ethanolamine (CDP-etn) to increase the production of PE from the CDP-etn pathway reversed high glucose and FFA (HG&FFA)-induced mitochondrial damage including increased apoptosis, decreased ATP synthesis, decreased mitochondrial membrane potential, and increased reactive oxygen species, whereas supplementation with lysophosphatidylethanolamine, which can increase PE production in the phosphatidylserine decarboxylase pathway, did not. Additionally, we found that overexpression of PCYT2 significantly ameliorated ATP synthesis and abnormal mitochondrial morphology induced by HG&FFA. Finally, the BAX/Bcl-2/caspase3 apoptosis pathway was activated in hepatocytes of the T2DM model, which could also be reversed by CDP-etn supplements and PCYT2 overexpression. In summary, in the liver of T2DM mice, Pcyt2 reduction may lead to a decrease in the levels of PE, whereas CDP-etn supplementation and PCYT2 overexpression ameliorate partial mitochondrial function and apoptosis in HG&FFA-stimulated L02 cells

Comparison of diabetic nephropathy between male and female eNOS\u3csup\u3e−/−\u3c/sup\u3e \u3ci\u3edb\u3c/i\u3e/\u3ci\u3edb\u3c/i\u3e mice

Sex is an important biological variable that impacts diverse physiological and pathological processes, including the progression of diabetic nephropathy. Diabetic nephropathy is one of the most common complications of diabetes mellitus and is the leading cause of end-stage renal disease. The endothelial nitric oxide synthase-deficient (eNOS−/−) db/ db mouse is an appropriate and valuable model to study mechanisms in the development of diabetic nephropathy because of the similarities of the features of diabetic kidney disease in this model to those in humans. The aim of the present study was to determine whether there was a sex difference in renal injury in eNOS−/− db/ db mice. Both male and female eNOS−/− db/ db mice showed hyperglycemia, obesity, and renal hypertrophy. However, there was no significant difference in those variables between male and female mice. Furthermore, both male and female diabetic mice showed progressive albuminuria and significantly greater levels of serum creatinine and blood urea nitrogen compared with the same sex of wild-type mice (nondiabetic controls). Although all three variables in female eNOS−/− db/ db mice had a tendency to be greater than those in male eNOS−/− db/ db mice, those sex differences were not statistically significant. Moreover, both male and female eNOS−/− db/ db mice showed significant mesangial expansion, higher glomerular injury scores, profound renal fibrosis, and substantial accumulation of fibronectin and collagen type IV proteins. However, sex differences in those structural changes were not observed. Similarly, survival rates of male and female eNOS−/− db/ db mice were comparable. Taken together, the results from the present study suggest no sex difference in renal structural and functional damage in eNOS−/− db/ db mice