Chandrama Shrestha

Enhanced Healing of Diabetic Wounds by Subcutaneous Administration of Human Umbilical Cord Derived Stem Cells and Their Conditioned Media

Objective. Mesenchymal stem cells (MSCs) isolated from the umbilical cord and their conditioned media (CM) can be easily obtained and refined compared with stem cells from other sources. Here, we explore the possibility of the benefits of these cells in healing diabetic wounds. Methodology and Results. Delayed wound healing animal models were established by making a standard wound on the dorsum of eighteen db/db mice, which were divided into three groups with six mice in each: groups I, II, and III received PBS, UC-MSC, and CM, respectively. UC-MSC and their CM significantly accelerated wound closure compared to PBS-treated wounds, and it was most rapid in CM-injected wounds. In day-14 wounds, significant difference in capillary densities among the three groups was noted (n = 6; P < 0.05), and higher levels of VEGF, PDGF, and KGF expression in the CM- and UC-MSC-injected wounds compared to the PBS-treated wounds were seen. The expression levels of PDGF-β and KGF were higher in CM-treated wounds than those in UC-MSC-treated wounds. Conclusion. Both the transplantation of UC-MSC and their CM are beneficial to diabetic wound healing, and CM has been shown to be therapeutically better than UC-MSC, at least in the context of diabetic wound healing.

Changes in Adipokines following Laparoscopic Roux-en-Y Gastric Bypass Surgery in Chinese Individuals with Type 2 Diabetes Mellitus and BMI of 22-30 kg·m(-2.).

Aims. Although altered endocrine changes following bariatric surgery in morbidly obese patients with diabetes have been demonstrated by previous studies, little is known about their effects on low BMI patients of T2DM. We investigated the changes in adipokines and sICAM-1 in Chinese subjects with low BMI and T2DM after LRYGB and explored their relationship with postsurgical insulin sensitivity. Methods. Plasma levels of adiponectin, sICAM-1, fasting glucose, glycated hemoglobin, and fasting insulin and serum levels of visfatin were measured before and at three months after LRYGB in 33 T2DM patients with BMI of 22–30 kg·m−2. Results. Significant reductions in anthropometric measurements and indicators of glucose and lipid metabolism and moderate reductions in insulin resistance and fasting insulin were observed at three months after LRYGB. Postoperative adiponectin level (P < 0.001) was increased compared to the preoperative level, whereas visfatin (P < 0.001) and sICAM-1 (P < 0.001) were lower than that before surgery. Serum adiponectin negatively correlated with HOMA-IR and FIns both preoperatively and at three months after surgery, and visfatin positively correlated with HOMA-IR and FIns both preoperatively and postoperatively. Conclusion. Changes in adipokines were related to an improvement in postsurgical insulin sensitivity, which was predicted by weight loss after LRYGB even in low BMI patients with T2DM.

Phosphoprotein Phosphatase 1 Is Required for Extracellular Calcium-Induced Keratinocyte Differentiation

Extracellular calcium is a major regulator of keratinocyte differentiation in vitro and appears to play that role in vivo, but the mechanism is unclear. We have previously demonstrated that, following calcium stimulation, PIP5K1α is recruited by the E-cadherin-β-catenin complex to the plasma membrane where it provides the substrate PIP2 for both PI3K and PLC-γ1. This signaling pathway is critical for calcium-induced generation of second messengers including IP3 and intracellular calcium and keratinocyte differentiation. In this study, we explored the upstream regulatory mechanism by which calcium activates PIP5K1α and the role of this activation in calcium-induced keratinocyte differentiation. We found that treatment of human keratinocytes in culture with calcium resulted in an increase in serine dephosphorylation and PIP5K1α activation. PP1 knockdown blocked extracellular calcium-induced increase in serine dephosphorylation and activity of PIP5K1α and induction of keratinocyte differentiation markers. Knockdown of PLC-γ1, the downstream effector of PIP5K1α, blocked upstream dephosphorylation and PIP5K1α activation induced by calcium. Coimmunoprecipitation revealed calcium induced recruitment of PP1 to the E-cadherin-catenin-PIP5K1α complex in the plasma membrane. These results indicate that PP1 is recruited to the extracellular calcium-dependent E-cadherin-catenin-PIP5K1α complex in the plasma membrane to activate PIP5K1α, which is required for PLC-γ1 activation leading to keratinocyte differentiation.

In serum, higher parathyroid hormone but not lower vitamin D is associated with oral squamous cell carcinoma.

INTRODUCTION Vitamin D and calcium are known to regulate differentiation and proliferation of keratinocytes; they might potentially have a role in suppressing carcinogenesis in squamous epithelium. Serum parathyroid hormone (pth) is a sensitive indicator of calcium and vitamin D deficiency, and 25-hydroxyvitamin D [25(OH)D] is an established marker of vitamin D status. METHODS To determine whether levels of 25(OH)D, calcium, or pth in serum are associated with oral squamous cell carcinoma (oscc), we examined those parameters in serum collected from 70 patients with oscc and from an equal number of matched control subjects. RESULTS The results showed that intact pth was significantly higher in serum from oscc patients than in serum from control subjects. However, we observed no significant differences in 25(OH)D or calcium in serum from oscc patients and from control subjects. CONCLUSIONS We conclude that higher serum pth, but not lower serum vitamin D or calcium, is associated with oscc.

p120-Catenin Is Required for Dietary Calcium Suppression of Oral Carcinogenesis in Mice

Previous studies have shown that dietary calcium suppresses oral carcinogenesis, but the mechanism is unclear. p120‐catenin (p120) is a cytoplasmic protein closely associated with E‐cadherin to form the E‐cadherin–β‐catenin complex and may function as a tumor suppressor in the oral epithelium. To determine whether p120 is involved in the mechanism by which dietary calcium suppresses oral carcinogenesis, The normal, low, or high calcium diet was fed control mice (designated as floxed p120 mice) or mice in which p120 was specifically deleted in the oral squamous epithelium during the adult stage (designated as p120cKO mice). All mice were exposed to a low dose of oral cancer carcinogen 4‐nitroquinoline 1‐oxide and rates of oral squamous cell carcinoma (OSCC) and proliferation and differentiation in the cancerous and non‐cancerous oral epithelium of these mice were examined. The results showed that the low calcium diet increased rates of OSCC and proliferation of the non‐cancerous oral epithelium and decreased differentiation of the non‐cancerous oral epithelium, but had no effect on cancerous oral epithelium. In contrast, the high calcium diet had opposite effects. However, the effect of the dietary calcium on the rates of OSCC, proliferation, and differentiation of the non‐cancerous epithelium were not seen in p120cKO mice. Based on these results, we conclude that p120 is required for dietary calcium suppression of oral carcinogenesis and oral epithelial proliferation and dietary calcium induction of oral epithelial differentiation. J. Cell. Physiol. 232: 1360–1367, 2017.

Phosphatase and tensin homologue (PTEN)-induced putative kinase 1 reduces pancreatic β-cells apoptosis in glucotoxicity through activation of autophagy

Chronic elevated glucose is harmful to pancreatic β-cells, resulting in pancreatic β-cells dysfunction and apoptosis. Understanding the molecular mechanisms associated with β-cells survival is pivotal for the prevention of β-cells injury caused by glucotoxicity. The role of Phosphatase and tensin homologue (PTEN)-induced putative kinase 1 (PINK1) in the fate of pancreatic β-cells constantly exposed to high glucose was studied. Sustained high glucose increased PINK1 protein expression both in rat pancreatic β-cells and INS-1 β-cells, and that this increase can be inhibited by PINK1 knockdown and further enhanced by PINK1 over-expression. PINK1 deficiency aggravated glucotoxicity-induced pancreatic β-cells apoptosis and inhibition of autophagy whereas PINK1 could reverse these adverse effects. This study provides fundamental data supporting the potential protective role of PINK1 as a new therapeutic target necessary to preserve β-cells survival under non-physiological hyperglycemia conditions.

p120-catenin is required for regulating epidermal proliferation, differentiation, and barrier function

p120‐catenin (p120) is an important regulator in the function and stability of E‐cadherin. However, the role of p120 in the epidermis is unclear. Previous studies have shown that globally knockout of p120 caused increased epidermal proliferation but little changes in epidermal differentiation and permeability. In the present study, we generated a conditional knockout mouse model and examined epidermal proliferation, differentiation and permeability. The results showed that conditional knockout of p120 in the epidermis caused not only increased epidermal proliferation but also decreased epidermal differentiation and increased permeability. These data suggest that p120 is required for suppressing epidermal proliferation, promoting epidermal differentiation and maintaining permeability barrier function of the epidermis.

Regulation of 25-hydroxyvitamin D-1-hydroxylase and 24-hydroxylase in keratinocytes by PTH and FGF23

Renal 25‐hydroxyvitamin D‐1α‐hydroxylase (1αOHase, CYP27B1) and 24‐hydroxylase (24OHase, CYP24A1) are tightly regulated. However, little is known about the regulation of 1α(OH)ase and 24(OH)ase in extrarenal tissue such as the epidermis. This study was to determine the roles of parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF 23) in the regulation of 1α(OH)ase and 24(OH)ase in epidermal keratinocytes as well as epidermal keratinocyte proliferation and differentiation. The results showed that PTH increased the protein level of 1α(OH)ase in human epidermal keratinocyte cell line HaCaT, but had no effect on the level of 24(OH)ase. The effect of PTH on 1α(OH)ase was blocked by the PKC inhibitor. Treatment with FGF23 decreased mRNA and protein levels of 1α(OH)ase and increased mRNA and protein levels of 24(OH)ase in HaCaT cells. The effect of FGF23 on 1α(OH)ase and 24(OH)ase was blocked by the mitogen‐activated protein kinase/extracellular regulated protein kinase (MAPK/ERK) inhibitor. In addition, treatment with PTH enhanced levels of differentiation markers including keratin 1, involucrin, loricrin, and filaggrin but reduced levels of BrdU incorporation in HaCaT cells. These effects were inhibited by the PKC inhibitor. FGF23 enhanced proliferation of HaCaT cells, but reduced levels of early differentiation markers including keratin 1 and involucrin and enhanced levels of the later differentiation markers including loricrin and filaggrin. These results suggest that PTH stimulates 1α(OH)ase expression and differentiation of HaCaT cells and inhibits proliferation via PKC. The data also suggest that FGF23 inhibits 1α(OH)ase expression and stimulates 24(OH)ase expression via MAPK/ERK. In addition, FGF23 enhances proliferation and late differentiation and inhibits early differentiation of HaCaT keratinocytes.