Trpc6 knockout protects against renal fibrosis by restraining the CN‑NFAT2 signaling pathway in T2DM mice

Diabetic kidney disease (DKD), one of the common complications of type‑2 diabetes mellitus (T2DM), has become the principal cause of end‑stage kidney disease. Transient receptor potential channel 6 (TRPC6), one of non‑selective cation channels with significant calcium‑permeability, is associated with renal fibrosis. However, the mechanism of TRPC6 in T2DM‑induced renal fibrosis is still not entirely understood. The present study explored the potential mechanism of Trpc6 knockout in T2DM‑induced renal fibrosis in Trpc6‑/‑ mice. The results showed that Trpc6 knockout inhibited the loss of body weight and the increase of fasting blood glucose (FBG) and significantly improved renal dysfunction and glomerular fibrosis in T2DM mice. The present study also indicated that Trpc6 knockout significantly lowered the expression of phosphorylated (p‑)SMAD2/3, TGF‑β, calcineurin (CN), nuclear factor of activated T‑cell (NFAT)2 and Nod‑like receptor (NLR) 3 inflammasome‑associated proteins. Calcium imaging results revealed that Trpc6 knockdown could decrease the levels of [Ca2+]i and inhibited calcium homeostasis imbalance. Moreover, it was found that knockout of Trpc6 had no significant influence on lipid disposition and reactive oxygen species generation in the kidney cortex. The present study suggested that knockout of Trpc6 may alleviate glomerular fibrosis and delay DKD progression by reducing [Ca2+]i overload and inhibiting the CN‑NFAT2 pathway in T2DM mice.

Analysis of 6 pediatric nephrotic syndrome cases with complications of cerebral sinovenous thrombosis and literature review

Background

Cerebral venous sinus thrombosis (CVST) is a rare but serious complication of nephrotic syndrome (NS) in children. To investigate the clinical characteristics of CVST in children with NS in order to timely diagnose this complication and reduce poor outcome.

Methods

Collect and analyze clinical data and magnetic resonance venography (MRV) results of children with NS complicated with CVST.

Results

Data of 6 patients with NS complicated with CVST were collected. 4 of the patients were steroid-sensitive nephrotic syndrome (SSNS) and 2 were steroid-resistant nephrotic syndrome (SRNS). The occurrence of CVST was observed within a time frame ranging from 12 days to 3 years following the diagnosis of NS. One patient had two episodes of thrombosis in three years, while the other five patients had only one episode of thrombosis. All patients had proteinuria at the time of episode of thrombosis. All patients presented with headache, and three of them had strabismus, seizures, and transient blindness, respectively. Neurological examination was negative. All patients were diagnosed with CVST by MRV within 3-16 days of the onset of headache. Two patients had TRPC6 gene mutation. All patients had resolution of neurological symptoms after anticoagulation treatment.

Conclusion

CVST may occur in the early stages of NS. There is currently a lack of specific diagnostic indicators to reliably identify the presence of CVST in patients with NS. Children with NS who have neurological symptoms should be promptly evaluated with imaging studies. Whether TRPC6 gene mutation is also a risk factor for CVST remains to be further studied.

The Role of Transient Receptor Potential Channel 6 Channels in the Pulmonary Vasculature

Canonical or classical transient receptor potential channel 6 (TRPC6) is a Ca²⁺-permeable non-selective cation channel that is widely expressed in the heart, lung, and vascular tissues. The use of TRPC6-deficient (“knockout”) mice has provided important insights into the role of TRPC6 in normal physiology and disease states of the pulmonary vasculature. Evidence indicates that TRPC6 is a key regulator of acute hypoxic pulmonary vasoconstriction. Moreover, several studies implicated TRPC6 in the pathogenesis of pulmonary hypertension. Furthermore, a unique genetic variation in the TRPC6 gene promoter has been identified, which might link the inflammatory response to the upregulation of TRPC6 expression and ultimate development of pulmonary vascular abnormalities in idiopathic pulmonary arterial hypertension. Additionally, TRPC6 is critically involved in the regulation of pulmonary vascular permeability and lung edema formation during endotoxin or ischemia/reperfusion-induced acute lung injury. In this review, we will summarize latest findings on the role of TRPC6 in the pulmonary vasculature.

Role of transient receptor potential channel 6 in the odontogenic differentiation of human dental pulp cells

Pulp capping is a restorative technique employed in an attempt to maintain pulpal vitality and generate reparative dentin. Ca²⁺ released from capping materials is suggested to promote reparative dentin formation. Transient receptor potential channel 6 (TRPC6) is a receptor-operated Ca2+ channel that serves an important role in Ca2+ influx in the majority of non-excitable cells, and influences the calcium signaling and cell respond. Therefore, the purpose of the present study was to gain an insight into the role of TRPC6 in the odontoblastic differentiation of human dental pulp cells (HDPCs). Human dental pulp tissues and HDPCs were obtained from healthy third molars. By immunohistochemical staining, TRPC6 was observed to be highly expressed in the dental pulp tissue, particularly in the odontoblast layer. In addition, the protein level of TRPC6 was increased in a time-dependent manner during odontogenic differentiation of HDPCs. Downregulation of TRPC6 by a lentivirus vector containing TRPC6 shRNA inhibited the process of odontogenic differentiation in HDPCs. In conclusion, the current data demonstrated that TRPC6 served a significant role in the odontogenic differentiation of HDPCs, suggesting it may be a promising therapeutic target in regenerative endodontics.

Antialbuminuric actions of calcilytics in the remnant kidney

Hyperphosphatemia accelerates the progression of chronic kidney diseases. In the present study, the effects of ronacaleret, a calcilytic agent, on renal injury were assessed in the following four groups of rats: 5/6-nephrectomized Wistar rats as a control (C group), rats treated with ronacaleret (3 mg·kg(-1)·day(-1); R group), rats treated with calcitriol (30 ng·kg(-1)·day(-1); V group), and rats treated with both ronacaleret and calcitriol (R + V group). Three months later, rats were euthanized under anesthesia, and the remnant kidneys were harvested for analysis. Albuminuria was lower in the R and V groups than in the C group (P < 0.05). Creatinine clearance was elevated in the R and V groups compared with the C group (P < 0.05). Serum Ca(2+) and renal ANG II were higher in the R + V group than in the C group (P < 0.05 for each), and serum phosphate was reduced in the R group compared with the C group (P < 0.05). Fibroblast growth factor-23 was lower in the R group and higher in the V and R + V groups than in the C group. However, parathyroid hormone did not differ significantly among the four groups. Renal klotho expression was elevated in the R and V groups compared with the C group (P < 0.05). The present data indicate that ronacaleret preserves klotho expression and renal function with reductions in serum phosphate and albuminuria in 5/6-nephrectomized rats. Our findings demonstrate that vitamin D prevents declines in klotho expression and renal function, suppressing albuminuria.