Inhibition of YAP activation attenuates renal injury and fibrosis in angiotensin II hypertensive mice

Hippo/YAP (yes-associated protein) pathway is an important signaling pathway to control organ development and tissue homeostasis. YAP is a downstream effector of Hippo pathway and a critical mediator of mechanic stress. Hypertensive nephropathy is characterized with glomerular sclerosis stiffness and renal fibrosis. The present study investigated the role of YAP pathway in angiotensin (Ang) II hypertensive renal injury by using YAP activation inhibitor verteporfin. Ang II increased the protein expression of YAP in renal nucleus fraction, decreased p-YAP and p-LATS1/2 expressions in renal cytoplasmic fraction, suggesting Ang II activation of renal YAP. Ang II significantly increased systolic blood pressure (SBP), proteinuria, glomerular sclerosis and fibrosis, treatment with verteporfin attenuated Ang II-induced proteinuria and renal injury with a mild reduction in SBP. Moreover, Ang II increased the protein expressions of inflammatory factors including tumor necrosis factor α, interleukin 1β and monocyte chemoattractant protein-1, and profibrotic factors including transform growth factor β, phosphor-Smad3 and fibronectin. Verteporfin reversed Ang II-induced above-mentioned molecule expressions. Our results for the first time demonstrate that the activation of the YAP pathway promotes hypertensive renal inflammation and fibrosis, which may promote hypertensive renal injury. YAP may be a new target for prevention and treatment of hypertensive renal diseases.

Hambatan Mesenchymal Stem Cell Terhadap Proliferasi Limfosit T

Mesenchymal stem cells (MSCs) are a kind of stem cells that can differentiate into several kinds of mesodermal cell decent. MSCs can be cultured in vitro therefore it can serve many purposes. However, MSCs also have immunosuppresion effects, one of the way is by suppresing T cell proliferation. MSCs need cell-to-cell contact with activated T cells in certain rasio to release it’s surppresion properties. Primery help from inflamatory cytokines is also needed. MSCs’s suppresion effect can be mediated by several molecules such as indoleamine 2,3-dioxygenase (IDO), inducible nitric-oxide synthase (iNOS), prostaglandin E2 (PGE2), transform growth factor-β (TGF-β), hepatocyte growth factor (HGF), and HLA-G5 soluble. MSCs’s characteristic and culture conditions can affect clinical applications.Keywords: Mesenchymal stem cells, T cell proliferation, immunosuppresion AbstrakMesenchymal stem cells (MSC) adalah salah satu jenis stem cell yang dapat berdiferensiasi menjadi beberapa macam turunan sel mesodermal. MSC dapat dikembangkan secara in-vitro sehingga memiliki banyak kegunaan. Namun, MSC juga dapat memberikan beberapa efek imunosupresi, salah satunya dengan cara menekan proliferasi sel T. Untuk melakukan supresi, MSC memerlukan kontak cell-to-cell dengan sel T teraktivasi dengan rasio tertentu. MSC juga membutuhkan bantuan awal dari sitokin inflamasi. Efek supresi MSC dapat diperantarai oleh beberapa molekul seperti indoleamine 2,3-dioxygenase (IDO), inducible nitric- oxide synthase (iNOS), prostaglandin E2 (PGE2), transform growth factor-β (TGF-β), hepatocyte growth factor (HGF), dan HLA-G5 terlarut. Sifat dan kondisi biakan MSC dapat mempengaruhi aplikasi klinis.Kata kunci: Mesenchymal stem cells, proliferasi sel T, imunosupresi

Enhanced bioactivity of transform growth factor-β1 from sulfated chitosan microspheres for in vitro chondrogenesis of mesenchymal stem cells

Transform growth factor-β1 (TGF-β1) is an extremely powerful protein to induce the chondrogenesis of mesenchymal stem cells (MSCs) both in vitro and in vivo. However, due to the short-life of TGF-β1, the direct application of TGF-β1 may deteriorate its bioactivity and thereby the repair effect. In this study, uniform sulfated chitosan microspheres (SCMs) with a mean diameter of ∼ 2 μm were fabricated by membrane emulsification as a carrier for TGF-β1. The in vitro release study showed that TGF-β1 could be sustainedly released from the microspheres up to 16 days. Under the protection of SCMs, about 13 % TGF-β1 was preserved even after stored for 14 days. The microspheres cytotoxicity was evaluated by coculture of MSCs with different concentrations SCMs and no obvious deterioration of cell viability was observed when the concentration of SCMs is lower than 2 μg/1.0 × 104 cells. In comparison with the blank group, the addition of TGF-β1 either in free state or loaded in SCMs inhibited the proliferation trend of MSCs. Quantitative analysis of GAGs production and genes expression of COL II and aggrecan by qRT-PCR revealed that enhanced bioactivity of TGF-β1 was obtained in the group of TGF-β1/SCMs, indicating that SCMs could be functioned as a promising carrier of TGF-β1 for the in vitro chondrogenesis of MSCs.

Euonymus alatus in the Treatment of Diabetic Nephropathy in Rats

Diabetic nephropathy is a leading cause of chronic renal failure. Recently, Euonymus alatus showed therapeutic potential in the treatment of diabetes and its chronic complications. In this study, effects of Euonymus alatus and its mechanism in the treatment of diabetic nephropathy were investigated. Diabetic nephropathy was induced in Sprague-Dawley rats by uninephrectomy plus streptozotocin (STZ) administration. Euonymus alatus and irbesartan, as a positive control, were lavaged to these rats for 12 weeks. Our data showed that Euonymus alatus was efficient in lowering HbA1c, improving blood lipids, decreasing 24 h urine protein and protecting kidney function. Pathological studies found kidney damage, including extracellular matrix expansion and glomerulosclerosis, were improved by Euonymus alatus treatment. Further investigation found that the herb had a role in downregulating the expression of transform growth factor β1. In conclusion, Euonymus alatus has a protective role in diabetic nephropathy, which may be related to its downregulation of transform growth factor β1 expression.

Targeted inhibition of FLT3 overcomes the block to myeloid differentiation in 32Dcl3 cells caused by expression of FLT3/ITD mutations

Internal tandem duplication (ITD) mutations of the juxtamembrane domain–coding sequence of the FLT3 gene are found in up to 34% of patients with acute myeloid leukemia (AML) and are associated with a poor prognosis. FLT3/ITDs result in constitutive activation of the tyrosine kinase domain and transform growth factor–dependent cell lines. FLT3 activation leads to antiapoptotic and proliferative signals, but little is known about the impact of FLT3/ITDs on differentiation. This study was designed to investigate the effect of FLT3/ITD expression on the differentiation of the 32Dcl3 (32D) myeloblastic cell line to neutrophils in response to granulocyte colony-stimulating factor (G-CSF). Expression of FLT3/ITD completely blocked morphologic differentiation and induction of myeloperoxidase (MPO), lysozyme, and CCAAT/enhancer-binding protein ε (C/EBPε) in response to G-CSF. Wild-type FLT3 and vector-transfected 32D cells were able to differentiate, although the maturation of FLT3-transfected cells was delayed by FLT3 ligand (FL) stimulation. CEP-701, a potent FLT3 tyrosine kinase inhibitor, overcame the morphologic block in differentiation caused by FLT3/ITD expression and allowed G-CSF induction of myeloid maturation markers. These findings suggest that blocking differentiation may be one of the mechanisms by which FLT3/ITDs contribute to leukemogenesis. CEP-701 and other FLT3 inhibitors may be useful for overcoming the block to differentiation (as well as the block to apoptosis) in the leukemic cells of patients with AML.