Inhibition of RhoA/ROCK signaling pathway ameliorates hypoxic pulmonary hypertension via HIF-1α-dependent functional TRPC channels.

Hypoxic pulmonary vasoconstriction (HPV) can be modulated by Rho/Rho kinase signaling, which can alter HPV vascular function via regulating myosin light chain phosphorylation, in a manner generally believed to be Ca2+-independent. We hypothesized that the RhoA/ROCK signaling pathway also can regulate HPV vascular function via a Ca2+-dependent mechanism, signaling through the functional transient receptor potential canonical (TRPC) channels. In this study, male BALB/c mice were exposed to normoxic or 10% oxygen (hypoxic) conditions for six weeks, after which systolic pressure and right ventricular hypertrophy were assessed. Transient intracellular calcium was monitored using a fluorescence imaging system. Muscle tension was measured with a contractile force recording system, and protein expression was assessed by immunoblotting. We found that the expressions of RhoA and ROCK were increased in mouse pulmonary arteries (PAs) under conditions of chronic hypoxia. Inhibition of the RhoA/ROCK signaling pathway prevented the development of hypoxic pulmonary hypertension (HPH), as evidenced by significantly reduced PA remodeling and pulmonary vasoconstriction. Immunoblotting results revealed that inhibition of the RhoA/ROCK signaling pathway significantly decreased the expression of HIF-1α. Knockdown of HIF-1α down-regulated the expression and function of the TRPC1 and TRPC6 channels in PASMCs under conditions of hypoxia. Contraction of the PAs and a Ca2+ influx into PASMCs through either receptor- or store-operated Ca2+ channels were also increased after hypoxia. However, RhoA/ROCK inhibitors markedly attenuated these changes. These results indicate that inhibition of the RhoA/ROCK signaling pathway ameliorates HPH via HIF-1α-dependent functional TRPCs.

PFKFB3 promotes endotoxemia-induced myocardial dysfunction through inflammatory signaling and apoptotic induction.

Cardiac dysfunction is a vital complication during endotoxemia (ETM). Accumulating evidence suggests that enhanced glycolytic metabolism promotes inflammatory and myocardial diseases. In this study, we performed deep mRNA sequencing analysis on the hearts of control and lipopolysaccharide (LPS)-challenged mice (40 mg/kg, i.p.) and identified that the glycolytic enzyme, 6-phosphofructo-2-kinase (PFK-2)/fructose-2,6-bisphosphatase 3 (PFKFB3) might play an indispensable role in ETM-induced cardiac damage. Quantitative real-time PCR validated the transcriptional upregulation of PFKFB3 in the myocardium of LPS-challenged mice and immunoblotting and immunostaining assays confirmed that LPS stimulation markedly increased the expression of PFKFB3 at the protein level both in vivo and in vitro. The potent antagonist 3-(3pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3PO) was used to block PFKFB3 activity in vivo (50 mg/kg, i.p.) and in vitro (10 µM). Echocardiographic analysis and TUNEL staining showed that 3PO significantly alleviated LPS-induced cardiac dysfunction and apoptotic injury in vivo. 3PO also suppressed the LPS-induced secretion of tumor necrosis factor-α, interleukin (IL)-1ß, IL-6 and lactate in the serum, in addition to lactate in the myocardium. PFKFB3 inhibition also diminished the nuclear translocation and phosphorylation of transcription factor nuclear factor-κB (NF-κB) in both adult cardiomyocytes and HL-1 cells. Furthermore, immunoblotting analysis showed that 3PO inhibited LPS-induced apoptotic induction in cardiomyocytes. Taken together, these findings demonstrate that PFKFB3 participates in LPS-induced cardiac dysfunction via mediating inflammatory and apoptotic signaling pathway.

Effect of erythrocytes on brain water content and haem oxygenase-1 expression in rats with traumatic intracerebral haemorrhage.

BACKGROUND: Studies have demonstrated that brain oedema formation following spontaneous intracerebral haemorrhage is associated with substances derived from blood clots or blood components. However, these studies did not completely reveal the role of blood components in brain oedema formation following traumatic intracerebral haemorrhage (TICH). Here, we explore the role of erythrocytes in brain oedema development by studying the effect of erythrocytes on brain water content (BWC) and expression of haem oxygenase-1 (HO-1) in rats with TICH. METHODS: A total of 120 Sprague-Dawley rats were randomly divided into four experimental treatment groups: traumatic brain injury (TBI), TBI plus whole blood (WB), TBI plus lysed red blood cells (RBCs; LRBC) and TBI plus packed RBCs (PRBC). Following TBI, which was established by applying a free-falling device, WB, LRBC or PRBC were infused with stereotactic guidance into the injured cortex to produce a model of TICH. All rats were killed at 1, 3 or 5 days after TBI or TICH. BWC was measured, and immunohistochemistry for HO-1 was performed. RESULTS: In the WB, PRBC and TBI groups, BWC at 3 days post-TBI or post-TICH was the greatest. However, BWC in the LRBC group at 1 day was markedly higher than that at 3 and 5 days. Comparisons among the four groups showed that BWC in the LRBC group was the highest at 1 day, and the highest at 3 days in the WB and PRBC groups; there was no significant difference at 5 days. Positive expression of HO-1 in the WB, PRBC and LRBC groups coincided with changes in BWC. CONCLUSIONS: Our results indicate that erythrocytes play an important role in delayed brain oedema formation (3 days post-injury) following TICH, but have no significant influence on brain oedema at early stages (1 day post-injury), and that the mechanisms of delayed brain oedema involve RBC breakdown products.

Cardioprotective effects of galectin-3 inhibition against ischemia/reperfusion injury.

Myocardial ischemia/reperfusion (IR) injury is caused by the restoration of the coronary blood flow following an ischemic episode. Accumulating evidence suggests that galectin-3, a ß-galactoside-binding lectin, acts as a biomarker in heart disease. However, it remains unclear whether manipulating galectin-3 affects the susceptibility of the heart to IR injury. In this study, RNA sequencing (RNA-seq) analysis identified that Lgals3 (galecin-3) plays an indispensable role in IR-induced cardiac damage. Immunostaining and immunoblot assays confirmed that the expression of galectin-3 was markedly increased in myocardial IR injury both in vivo and in vitro. Echocardiographic analysis showed that cardiac dysfunction in experimental IR injury was significantly attenuated by galectin-3 inhibitors including pectin (1%, i.p.) from citrus and binding peptide G3-C12 (5.0 mg/kg, i.p.). Galectin-3 inhibitor-treated mice exhibited smaller infarct sizes and decreased tissue injury. Furthermore, TUNEL staining showed that galectin-3 inhibition suppressed IR-mediated cardiomyocyte apoptosis. Mitochondrial membrane potential (MMP) and mitochondrial permeability transition pore (mPTP) levels were well-preserved and IR-induced changes of mitochondrial cyto c, cytosol cyto c, caspase-9, caspase-3, Bcl-2 and Bax in the galectin-3 inhibitor-treated groups were observed. Our findings indicate that the pathological upregulation of galectin-3 contributes to IR-induced cardiac dysfunction and that galectin-3 inhibition ameliorates myocardial injury, highlighting its therapeutic potential.

[Soil contamination and assessment of heavy metals of Xiangjiang River Basin].

The contents of heavy metals (As, Cd, Cu, Zn, Ni and Pb) in soils from Xiangjiang River Basin, Hunan Province, China, were analyzed by toxicity characteristic leaching procedure (TCLP) and Nemrow method. Results showed that the total contents of As, Cd, Cu, Zn, Ni and Pb were 4.25-549.67, 0.13-76.84, 11.49-281.69, 7.75-7234.81, 5.50-56.65 and 8.60-2084.81 mg x kg(-1), respectively, and the available contents of As, Cd, Cu, Zn, Ni and Pb extracted by TCLP were 0.02-10.97, 0.06-28.41, 0.04-72.29, 0.59-1 152.32, 0.07-10. 65 and 0.17-1 165.58 mg x kg(-1). The contents of available heavy metals extracted by TCLP correlated with total contents of heavy metals. Moreover, the pollution index Nemrow method showed that 72 samples at safety level, alert level, light pollution level, medium pollution level and heavy pollution level ratios were 60.52%, 11.33%, 5.65%, 4.22% and 18.38% separately, illustrating that pollution of heavy metals in soil samples of Xiangjiang River Basin is serious.