Knockdown of NYGGF4 increases glucose transport in C2C12 mice skeletal myocytes by activation IRS-1/PI3K/AKT insulin pathway.

NYGGF4, an obesity-related gene, is proposed to be involved in the development of insulin resistance. Skeletal muscle is a primary target organ for insulin and NYGGF4 showed a relatively high expression level in skeletal muscle. Therefore, this study aimed to explore the effect of NYGGF4 on insulin sensitivity of skeletal muscle cells. RNA interference (RNAi) was adopted to silence NYGGF4 expression in mice C2C12 skeletal myocytes. A remarkably increased insulin-stimulated glucose uptake and GLUT4 translocation was observed in NYGGF4 silencing C2C12 cells. Importantly, the enhanced glucose uptake induced by NYGGF4 silencing could be abrogated by the PI3K inhibitor LY294002. In addition, the crucial molecules involved in PI3K insulin signaling pathway were detected by western blotting. The results showed that NYGGF4 knockdown dramatically activate the insulin-stimulated phosphorylation of IRS-1 and AKT. Taken together, these data demonstrate that NYGGF4 knockdown increases glucose transport in myocytes by activation of the IRS-1/PI3K/AKT insulin pathway.

[Relationship between renal Th1/Th2 ratio and renal microvascular injury in children with Henoch-Sch-nlein purpura nephritis].

OBJECTIVE: To explore possible correlations between renal Th1/Th2 ratio and renal microvascular injury in children with Henoch-Sch-nlein purpura nephritis (HSPN). METHODS: Thirty-two children with HSPN were enrolled. They were classified into four groups by renal pathology: HSPN class II (n=8), HSPN class IIIa (n=7), HSPN class IIIb (n=10) and HSPN class IV/V (n=7). Five patients undergoing nephrectomy due to trauma were used as the controls. INFγ, IL-4 and CD34 in the renal tissues were measured by immunohistochemical analysis. INFγ was used as a marker of Th1, IL-4 was used as a marker of Th2 and CD34 was used as a marker of microvessel. The renal microvessel density was evaluated according to the Weidner standard. The relationships among the local Th1/Th2 ratio, renal pathological grade, microvessel score and microvessel density were studied. RESULTS: Immunohistochemical analysis showed a lower expression of INFγ and a higher expression of IL-4 in the HSPN groups than in the control group. The local Th1/Th2 ratio in the HSPN groups decreased and correlated significantly with the renal pathological grade. There were significant differences among four HSPN subgroups (P<0.05). Compared with the control group, the renal microvessel density in the HSPN class II and class IIIa groups increased significantly (P<0.05), but it decreased in the HSPN class IV/V group (P<0.05). The renal microvessel scores in the HSPN class IIIa, class IIIb and class IV/V groups increased significantly compared with those in the control and the HSPN classⅡ. The increased renal microvessel scores were associated with more severe renal pathological changes. A negative correlation was found between the local Th1/Th2 ratio and the microvessel density in kidneys (r=-0.921, P<0.01). CONCLUSIONS: The decrease of Th1/Th2 ratio in kidneys might be responsible for renal microvascular injury in children with HSPN.

Effects of NYGGF4 knockdown on insulin sensitivity and mitochondrial function in 3T3-L1 adipocytes.

NYGGF4 is a recently discovered gene that is involved in obesity-associated insulin resistance. It has been suggested that mitochondrial dysfunction might be responsible for the development of insulin resistance induced by NYGGF4 overexpression. In the present study, we aimed to define the impact of down-regulating NYGGF4 expression by RNA interference (RNAi) on the insulin sensitivity and mitochondrial function of 3T3-L1 adipocytes. The results revealed that NYGGF4 knockdown enhanced the glucose uptake of adipocytes, which reconfirmed the regulatory function of NYGGF4 in adipocyte insulin sensitivity. However, an unexpected observation was that knockdown of NYGGF4 reduced intracellular ATP concentration and promoted an increase in mitochondrial transmembrane potential (ΔΨm) and reactive oxygen species (ROS) level without affecting mitochondrial morphology or mtDNA. Therefore, the role of NYGGF4 in mitochondrial function remains unclear, and further animal studies are needed to explore the biological function of this gene.

[Expression of vascular endothelial growth factor is related to microvessel injury of renal interstitium in children with Henoch Schönlein purpura nephritis].

OBJECTIVE: To investigate the relationship between vascular endothelial growth factor (VEGF) expression and microvessel injury of renal interstitium in children with Henoch-Schönlein purpura nephritis (HSPN). METHODS: Thirty-two children with HSPN and who had not received glucocorticoid or immunodepressants treatment before hospitalization were enrolled. Five children undergoing nephrectomy due to renal trauma were used as the control group. Renal samples were stained by hematoxylin and eosin and renal pathological changes were evaluated semi-quantitatively. CD34 and VEGF expression was detected by immunohistochemistry. CD34 was used as the marker for endothelial cells of renal microvessels. The microvessel density (MVD) was calculated by CD34 immunostaining. RESULTS: Compared with the control and the renal pathological grade II HSPN groups, MVD in the grade III and above HSPN groups decreased significantly, with an obvious reduction in MVD with the increased renal pathological grade (p<0.05). The renal microvessel score in the grades IIIa, IIIb, IV, and V HSPN groups decreased obviously compared with that in the control group. The renal microvessel score decreased with the increased renal pathological grade (p<0.05). VEGF expression in the grade II HSPN group was higher (p<0.05), while that in the grades IV and V HSPN group was lower than that in the control group (p<0.05). VEGF expression in the HSPN group showed a significant reduction with the increased renal pathological grade (p<0.05). There was a positive correlation between VEGF expression and MVD in renal tissue in the HSPN group (r=0.935, p<0.01). CONCLUSIONS: The decreased expression of VEGF may be responsible for the renal pathological damage and microvessel injury in HSPN.

[Protective effects of catechin on apoptosis of endothelial progenitor cells induced by H2O2 in rats].

OBJECTIVE: To study the effect of H2O2 on the proliferation and apoptosis of endothelial progenitor cells (EPCs) and the antogonistic effects of catechin on the cell apoptosis induced by H2O2 in rats. METHODS: Immuno-fluoreascence assay was applied to detect CD34, CD133 and VEGFR-2 expression. EPCs of generation 2 were divided into control cells, H2O2-treated cells and catechin-H2O2-treated cells (H2O2: 100 mg/L; catechin: 10 mg/L). Genomic DNA was extracted by the conventional method after intervention for the analysis of apoptosis ladder pattern. The MTT assay was applied to detect proliferation rate of EPCs. RESULTS: The cultured cells at day 10 expressed CD34, CD133 and VEGFR-2. DNA apoptosis ladder pattern appeared in H2O2-treated cells 2 days after intervention. After 3 days of intervention DNA apoptosis ladder pattern appeared in both H2O2-treated cells and H2O2-catechinjtreated cells, with more ladders and grayer scale in H2O2 -treated cells. Compared with the controls, H2O2-treated cells and H2O2-catechin-treated cells showed significantly decreased proliferation rate (p<0.01), with the lowest proliferation rate at the 2nd day (p<0.05). The H2O2-catechin-treated cells showed increased proliferation rate than H2O2-treated cells at the 1st, 2nd and 3rd days. CONCLUSIONS: H2O2 may impair EPCs proliferation and induce EPCs apoptosis. Catechin may increase the capacity of EPCs for the resistance to apoptosis induced by H2O2.

[Evidence-based therapy of nephrotic edema].

OBJECTIVE: To study the evidence-based therapy of edema in nephrotic syndrome by analyzing the literatures systematically. METHODS: The literatures related to the treatment of nephrotic edema were retrieved from the following: Chinese Biological Medicine Database (CBM-disk), Chinese Journals Full-text Database (CNKI, 1994-2006), Chinese Technological Periodicals Database (VIP, 1989-2006), Chinese Evidence Biological Medicine/Cochrane Central Database (CEBM/CCD), Cochrane Library Database, MEDLINE (1966-2006), EMBASE (1975-2006), MEDLARS, SCI (1985-2006) and OVID by electron and craft search with the following key words: nephrotic syndrome, edema, recalcitrant edema, refractory edema or resistant nephrotic edema, and treatment, diuretic therapy or human albumin treatment. The relevant literatures on randomized controlled trials (RCT) that met the criteria were statistically analyzed by the Coorporative network software RevMan 4.2. RESULTS: A total of 113 articles were searched (60 in Chinese and 53 in English), of which 12 were RCT. Three of the 12 articles were included for Meta analysis. Meta analysis showed that dextran-40 together with furosemide was effective for nephrotic edema. Human albumin solution could be used in nephrotic edema patients with coexistent severe hypoalbuminemia. A combination of diuretics by intravenous drip infusion was effective for diuretic-resistant nephrotic edema. CONCLUSIONS: The treatment for nephrotic edema should be individualized. The evidence of treatment of nephrotic edema has not been fully elucidated. Further multicentre, large sample, and randomized controlled trials are needed.