The role of the hypoxia-inducible factor 1 binding site in the induction of aquaporin-1 mRNA expression by hypoxia.

Aquaporin-1 (AQP1), a water channel protein, has been shown to play an important role in tumor growth and angiogenesis in mouse endothelial cells. We recently reported that the expression of AQP1 mRNA was induced in cultured human retinal vascular endothelial cells (HRVECs) under hypoxia. In the present study, HRVECs were cultured under normoxia or hypoxia (1% O(2)) to elucidate the mechanism of hypoxic induction of AQP1.

Protein tyrosine phosphatase regulation in fibroblasts from patients with an insulin receptor gene mutation.

Tyrosine phosphorylation of the insulin receptor is the initial event following receptor binding to insulin, and it induces further tyrosine phosphorylation of various intracellular molecules. This signaling is countered by protein tyrosine phosphatases (PTPases), which reportedly are associated with insulin resistance that can be reduced by regulation of PTPases. Protein tyrosine phosphatase 1B (PTP1B) and leukocyte antigen-related PTPase (LAR) are the PTPases implicated most frequently in insulin resistance and diabetes mellitus.

Increased urinary levels of CXCL5, CXCL8 and CXCL9 in patients with Type 2 diabetic nephropathy.

CXC chemokines are particularly significant for leukocyte infiltration in inflammatory diseases. Recent reports have shown that inflammation is one of potential pathogenic mechanisms for diabetic nephropathy. However, information on inflammation related with CXC chemokines in human Type 2 diabetic nephropathy still remains scarce.

Aquaporin 1 is required for hypoxia-inducible angiogenesis in human retinal vascular endothelial cells.

Aquaporin 1 (AQP1) was first purified from red blood cell membranes and is now known to be an osmolarity-driven water transporter that is widely expressed in many epithelial and endothelial cells outside the brain. Several recent studies have shown strong expression of AQP1 in proliferating tumor microvessels, suggesting that AQP1 may have an important role in tumor angiogenesis. Hypoxia is thought to be a common precursor to neovascularization in many retinal diseases, including diabetic retinopathy, and therefore we analyzed the expression pattern and function of AQP1 in human retinal vascular endothelial cells cultured under hypoxic conditions.

Regulation of Src homology 2-containing protein tyrosine phosphatase by advanced glycation end products: the role on atherosclerosis in diabetes.

Advanced glycation end products (AGEs), among the most important causes of atherosclerosis in diabetes mellitus, stimulate the proliferation of smooth muscle cells (SMCs). Smooth muscle cells are central in the formation of atherosclerotic lesions, where they show both increased migration and accelerated proliferation. In investigating how AGEs stimulate SMC proliferation, we focused on protein tyrosine phosphatase, especially Src homology 2-containing protein tyrosine phosphatase (SHP2), which is considered important in regulating cell proliferation.