Vascular smooth muscle-specific LRRC8A knockout ameliorates angiotensin II-induced cerebrovascular remodeling by inhibiting the WNK1/FOXO3a/MMP signaling pathway.

Hypertensive cerebrovascular remodeling involves the enlargement of vascular smooth muscle cells (VSMCs), which activates volume-regulated Cl- channels (VRCCs). The leucine-rich repeat-containing family 8 A (LRRC8A) has been shown to be the molecular identity of VRCCs. However, its role in vascular remodeling during hypertension is unclear. In this study, we used vascular smooth muscle-specific LRRC8A knockout (CKO) mice and an angiotensin II (Ang II)-induced hypertension model. The results showed that cerebrovascular remodeling during hypertension was ameliorated in CKO mice, and extracellular matrix (ECM) deposition was reduced. Based on the RNA-sequencing analysis of aortic tissues, the level of matrix metalloproteinases (MMPs), such as MMP-9 and MMP-14, were reduced in CKO mice with hypertension, which was further verified in vivo by qPCR and immunofluorescence analysis. Knockdown of LRRC8A in VSMCs inhibited the Ang II-induced upregulation of collagen I, fibronectin, and matrix metalloproteinases (MMPs), and overexpression of LRRC8A had the opposite effect. Further experiments revealed an interaction between with-no-lysine (K)-1 (WNK1), which is a "Cl--sensitive kinase", and Forkhead transcription factor O3a (FOXO3a), which is a transcription factor that regulates MMP expression. Ang II induced the phosphorylation of WNK1 and downstream FOXO3a, which then increased the expression of MMP-2 and MMP-9. This process was inhibited or potentiated when LRRC8A was knocked down or overexpressed, respectively. Overall, these results demonstrate that LRRC8A knockout in vascular smooth muscle protects against cerebrovascular remodeling during hypertension by reducing ECM deposition and inhibiting the WNK1/FOXO3a/MMP signaling pathway, demonstrating that LRRC8A is a potential therapeutic target for vascular remodeling-associated diseases such as stroke.

[Long-term clinical observation on the repair of large articular cartilage defects of the hip and the knee with free autogeneous periosteum].

OBJECTIVE: To observe the long-term clinical results of repairing large articular cartilage defects of the hip and the knee with free autogeneous periosteum. METHODS: Based on the results of experimental studies, the authors used free autogeneous periosteum transplantation and postoperative continuous passive motion (CPM) to repair large articular cartilaginous defects in 52 patients from February 1987 to August 1995. Of 37 patients with complete follow-up data, 16 had congenital dislocation of the hip, 6 traumatic arthritis of hip, 1 femoral head destruction following mild infection, 2 ankylosing spondylitis, 6 intra-articular fracture of the knee, 4 arthritis of the knee and 2 stiff knee following joint infection. The patients with dislocation of hip were given relieving traction before operation. The cartilages of pathological changes were excised to bleeding bone. The defects were repaired with periosteum removing from tibia. CPM were immediately applied for 4-6 weeks and no bearing was allowed 6 months after discharge. The silicon membrane was taken out in the 6th month. RESULTS: Thirty-seven patients (17 males, 20 females) were followed up 7-15 years with an average of 10.5 years. The functional evaluation referred to joint pain degree, joint mobile range, daily activity and X ray findings. The results were excellence in 11 patients, good in 18 patients, poor in 8 patients. CONCLUSION: The method to repair articular cartilage defect with free autogeneous periosteum is effective and may be applied clinically.

[Experimental study on repair of articular cartilage defect in large area with chondrocytes cultured on fascia].

OBJECTIVE: To study the biological characteristic and potential of chondrocytes grafting cultured on fascia in repairing large defect of articular cartilage in rabbits. METHODS: Chondrocytes of young rabbits were isolated and sub-cultured on fascia. The large defect of articular cartilage was repaired by grafts of freeze-preserved and fresh chondrocytes cultured on fascia, and free chondrocytes respectively; the biological characteristic and metabolism were evaluated by macroscopic, histological and immunohistochemical observations, autoradiography method and the measurement of nitric oxide content 6, 12, 24 weeks after grafting. RESULTS: The chondrocytes cultured on fascia maintained normal growth feature and metabolism, and there was no damage to chondrocytes after cryopreservation; the repaired cartilage was similar to the normal cartilage in cellular morphology and biological characteristics. CONCLUSION: Chondrocytes could be cultured normally on fascia, which could be used as an ideal carrier of chondrocytes.