The liver injury following ischemia and reperfusion is worse in experimental knockout heterozygote mouse model for expression of connexin 43

Abstract Purpose: To evaluate that Connexin (Cx43) plays a role in lesions after hepatic ischemia/reperfusion (IR) injury. Methods: We use Cx43 deficient model (heterozygotes mice) and compared to a wild group. The groups underwent 1 hour ischemia and 24 hours reperfusion. The heterozygote genotype was confirmed by PCR. We analyzed the hepatic enzymes (AST, ALT, GGT) and histology. Results: The mice with Cx43 deficiency showed an ALT mean value of 4166 vs. 307 in the control group (p<0.001); AST mean value of 7231 vs. 471 in the control group (p<0.001); GGT mean value of 9.4 vs. 1.7 in the control group (p=0.001); histology showed necrosis and inflammation in the knockout group. Conclusions: This research demonstrated that the deficiency of Cx43 worses the prognosis for liver injury. The topic is a promising target for therapeutics advancements in liver diseases and procedures.

Neuroprotective effects of gap junction blocker octanol on cerebral ischemia-reperfusion injury in rats may be associated with the alleviation of inflammatory response / 国际脑血管病杂志

Objective To investigate the effects of octanol,a gap junction blocker,on the levels of pro-inflammatory cytokines after cerebral ischemia-reperfusion in rats.Methods Seventy-two male SD rats were randomly divided into sham operation group,saline control group,vehicle group,and octanol intervention group (n =18 in each group).The model of transient middle cerebral artery occlusion was induced by the modified suture method.The octanol intervention group was intraperitoneally injected with octanol solution at 5 mmol/kg body weight 30 min before ischemia.The saline control group and the vehicle group were intraperitoneally injected with the same amount of physiological saline and 5％ dimethyl sulfoxide solution 30 min before procedure.The neurological deficit score,brain water content,and cerebral infarction volume in each group were detected after ischemia for 2 h and reperfusion for 24 h.Enzyme-linked immunosorbent assay was used to detect the serum interleukin (IL)-1β,IL-6,and tumor necrosis factor-α (TNF-α) levels.Results Compared with the saline control group and the vehicle group,the neurological deficit score of the octanol intervention group was significantly lower (all P ＜0.05),the brain tissue water content was significantly decreased (P ＜ 0.05),the cerebral infarction volume was significantly reduced (P ＜0.05),and the expression levels of IL-1β,IL-6,and TNF-α were significantly decreased (all P ＜0.05).There were no significant differences in neurological deficit score,brain water content,cerebral infarction volume and serum IL-1 [β,IL-6 and TNF-α levels between the saline control group and the vehicle group.Conclusion Gap junction blocker octanol can reduce cerebral ischemic-reperfusion injury.Its mechanism may be related to the alleviation of inflammatory response.

Formation of gap junctions between adipose stem cells-derived Schwann cells in a rat model of dyskinesia induced by brain injury / 南方医科大学学报

OBJECTIVE@#To investigate the formation of gap junctions between Schwann cells derived from differentiated adipose stem cells implanted in a rat model of dyskinesia induced by brain injury and its positive effect in promoting functional recovery of the rats.@*METHODS@#In a rat model of hemiplegia induced by motor cortex injury, adipose stem cells or Schwann cells differentiated from adipose stem cells, either with or without RNAi-mediated silencing of Cx43, were transplanted orthotopically in the lesion. The recovery of the motor function of the rats was observed and scored after the transplantation. Rat brain tissues were sampled to detect the expressions of nerve growth factor (NGF) using Western blotting and RT-PCR.@*RESULTS@#All the 3 cell transplantation therapies obviously improved the motor function scores of the rats as compared with the control rats. The expression of NGF in the brain tissue was significantly lower in the control group than in the cell transplantation groups. NGF expression in the brain tissues of rats receiving transplantation of Schwann cells with Cx43 gene silencing was lower than that in rats receiving Schwann cells without Cx43 silencing, and was similar with that in rats transplanted with adipose stem cells. The results of RT-PCR showed that NGF mRNA level in the control group was significantly lower than that in the other 3 groups. NGF mRNA expression was the highest in Schwann cell group without Cx43 silencing, followed by adipose stem cell group, and then by Schwann cell group with Cx43 silencing.@*CONCLUSIONS@#In the rat model of dyskinesia induced by brain injury, transplantations of adipose stem cells and adipose stem cells-derived Schwann cells both promote the functional recovery of brain damage, in which gap junction protein Cx43 plays an important role to promote functional gap junction formation possibly by enhancing NGF expression.

Roles and mechanisms of connexin 43 in cerebral ischemia-reperfusion / 国际脑血管病杂志

In the central nervous system, gap junctions exist between neurons and glial cells. Among them, connexin 43 (Cx43) is one of the most abundant connexin proteins in the central nervous system,involved in the metabolic coupling of intercellular substance exchange and electrical coupling of electrical signaling. It plays an important role in regulating cell metabolism, homeostasis, and cell differentiation. After cerebral ischemia, the uncoupling of gap junctions and abnormal hemichannel activity cause a steady-state imbalance of the internal and external environment of the cells, eventually leading to brain tissue damage.Therefore, maintaining the normal function of Cx43 is essential for protecting brain tissue from neuronal damage induced by cerebral ischemia-reperfusion.

cAMP transfer across MEGJ mediates regulatory effect of Ang2 on hypo-reactivity after hypoxia in vascular smooth muscle cells / 中国病理生理杂志

AIM:To observe the cyclic adenosine monophosphate(cAMP)transfer across myoendothelial gap junctions(MEGJ)in the regulatory effect of angiopoietin-2(Ang2)on hyporeactivity after hypoxia in vascular smooth mus-cle cells(VSMCs ).METHODS:The double-sided cell co-culture model of vascular endothelial cells(VECs )and VSMCs was set up.The protein expression of inducible nitric oxide synthase(iNOS)was determined by Western blot.The contraction of VSMCs was detected via the leakage of FITC-labeled bovine serum albumin.Alexa Fluor 488-cAMP was used as the tracer to observe the cAMP transfer across MEGJ from VECs to VSMCs.RESULTS:In cultured VECs and VSMCs alone ,the cAMP concentrations were both significantly increased after exogenous Ang 2 treatment and hypoxia ,and more in VECs than that in VSMCs(P<0.05).In the double-sided cell co-culture model,the difference was weakened,and the increase in cAMP concentration in VSMCs after exogenous Ang 2 treatment and hypoxia was antagonized by connexin 43(Cx43)small interfering RNA(siRNA)(P<0.05).Alexa Fluor 488-cAMP in VECs transfered into VSMCs after exoge-nous Ang2 treatment and hypoxia,which was also antagonized by Cx43 siRNA(P<0.05).The cAMP antagonist inhibited the protein expression of iNOS in the VSMCs and the hyporeactivity of the VSMCs after exogenous Ang 2 treatment and hy-poxia(P<0.05).CONCLUSION:Ang2 may regulate the protein expression of iNOS in VSMCs and the hyporeactivity of VSMCs after hypoxia through the cAMP transfer across MEGJ.

Progress in relationship between pannexin and tumors / 中国病理生理杂志

Pannexin is a new member of gap junction families which was discovered in 2000 and was widely distributed in humans. Pannexin forms hemichannels and participates in transmission of small molecules and many other pathophysiological processes. Recent studies have found that the abnormal expression of pannexin is related to occurrence and development of tumors. This article reviews the relationship between pannexin and tumors,and aims to provide new i-deas for treatment of tumors.

Visión celular y molecular de la ortopedia funcional de los maxilares

Actualmente, los mecanismos biológicos que subyacen a la estimulación ortopédica funcional están en proceso de entendimiento; sin embargo, se sabe que el osteocito juega un rol esencial, al recibir y transformar dicho estímulo funcional hacia una señal bioquímica, lo que da como consecuencia la secreción de diversas moléculas. Estas se movilizan entre los osteocitos, gracias a su extensa red de uniones comunicantes, y llegan en última instancia a activar a las células efectoras del tejido óseo: osteoblastos y osteoclastos. El objetivo de la revisión es actualizar y compendiar algunos de los más importantes mecanismos celulares y moleculares subyacentes a la terapia ortopédica funcional de los maxilares.

Currently, the biological mechanisms underlying functional orthopedic stimulation are in process of understanding. However, it is known that osteocyte plays an essential role, to receive and process the functional stimulus to biochemical signals giving as result the secretion of various molecules. Such molecules are mobilized between the osteocytes, thanks to its extensive network of gap junctions, ultimately coming to activate effector cells of bone tissue: osteoblasts and osteoclasts. The aim of the review is to update some of the cellular and molecular mechanisms underlying functional orthopedic therapy of the maxillary.

Enhanced cell gap junctions promotes the radiosensitivity in triple negative breast cancer cells / 实用肿瘤学杂志

Objectvi e To investigate whether promoting gap junctions may contribute to the radiosensi-tivity in triple negative breast cancer( TNBC)cells.Methods HCC70(triple-negative),MCF-7(ER-posi-tive)or SK-BR3(HER2-positive )cells were transfected with pcDNA/5 -Cx43 expression plasmid using liposome 2000.The transfected cells were treated with various doses of radiation(0,5,10,15 Gy),and the level of Cx43 protein was determined by Western blot and the cell connectivity was determined by fluorescent tracer technique. Cell proliferation inhibition,clone formation ability and apoptosis were detected using MTT,clone formation assay, AnnexinV-FITC/PI double staining and flow cytometer,respectively.Results The level of Cx43 protein signifi-cantly increased in HCC 70 -Cx43 ,MCF-7 -Cx43 and SK-BR3 -Cx43 cells.After transfection the cells were treated with various doses of radiation,level of Cx43protein was gradually enhanced in dose dependent fashion .The re-sults form fluorescent tracer technique showed that fluorescence intensity was gradually elevated with increase of radiation doses.Cell viability and clone formation ability were decreased gradually in dose dependent manner in HCC70-Cx43 ,MCF-7 -Cx43 and SK-BR3-Cx 43 cells.Unexpectedly,the inhibitive effect of proliferation ability and clone formation ability in HCC70 -Cx43 cell was higher than in MCF-7 -Cx43 and SK-BR3 -Cx43 cells under same conditions.The results from AnnexinV-FITC/PI and flow cytometer showed that apoptosis rate was enhanced gradually accompanying with increase of radiation doses.Conclu sion Enhancing the function of cell gap junc-tions promoted radiosensitivity of breast cancer cells,particularly in TNBC cells.Radiation can strengthen cell gap junctions in breast cancer cell and cytotoxicity of TNBC cell can be enhanced by both synergistic effects.

Research progress in mechanism of Astragali Radix and its active components on endothelial cells and their junction / 中草药

To summarize the research progress in vascular endothelial cells junction as well as mechanism of effective components in Yiqi Chinese medicine Astragali Radix in vascular endothelial cells junction based on referring literature in recent year. Astragalus polysaccharides and Astragalus saponins can protect the integrity of endothelial cells junction by increasing tight junction protein and decreasing endothelial cell adhesion molecule. Its protection takes effect by inhibiting endothelin secretion, increasing NO release, inhibiting apoptosis, and promoting endothelial cells proliferation and migration in angiogenesis in addition, while Astragalus flavonoids inhibits apoptosis to protect the junction of endothelial cells. The multiple-targeted protective effect of Astragali Radix in vascular endothelial cells involved in p38 MAPK/NF-κB, Rho/ROCK, PI3K/Akt, and VEGF/Ang-1 signaling pathways. The current study focused on tight junctions as well as adhesion molecule inhibition of monocyte adhesion to endothelial cells. But its protection of gap junctions has rarely been studied.

Mechanism of 17β-estrogen on intracellular free calcium regulation in smooth muscle cells at the ;endometrial-myometrial interface in uteri with adenomyosis / 中华妇产科杂志

Objective To investigate the regulation mechanism of estrogen on the free calcium of smooth muscle cells at the endometrial-myometrial interface (EMI) in uteri with adenomyosis. Methods From September 2011 to November 2012, 59 uterine myometrial specimens were obtained from 59 cases underwent hysterectomy, including 28 adenomyosis patients as adenomyosis (ADS) group and 31 patients with cervical intraepithelial neoplasia Ⅲ as control group. EMI smooth muscle cells were cultured and loaded with calcium ion fluorescent probe fluo-4/AM. After treated with trisphosphate (IP3) receptor antagonist, blocker of sarcoplasmic reticulum calcium-adenosine triphosphate (ATP), depleted agent of the ryanodine receptor-operated Ca2+, inhibitor of L-type calcium channel, inhibitor of Na+-Ca2+exchanger, the labeled cells were stimulated with estrogen. The changes of intracellular Ca2+fluorescence intensity were detected by laser scanning microscopy. The changes of intracellular Ca2+concentration was indicated byΔF[Ca2+]i. Results (1) Under normal calcium conditions, after the stimulation of estrogen, intracellular Ca2+fluorescence intensity in ADS group and control group both increased than those without estrogen. TheΔF[Ca2+]i in ADS group was 384±26, and in the control groupΔF[Ca2+]i was 235±20. TheΔF[Ca2+]i in ADS group was higher than that in the control (P0.05). But, the ΔF[Ca2 +]i in ADS group was significantly reduced after treatment compared to before treatment, (211 ± 19 vs 384 ± 28; P=0.001). The increase in control group was almost the same with before (203±16 vs 234±22, P=0.141). (4) After treated with inhibitor of Na+-Ca2+exchanger, theΔF[Ca2+]i in ADS group was 357 ± 24 and in the controlΔF[Ca2+]i was 209±19. The increase in ADS group was significant higher than that in the control (P=0.000). Compared withΔF[Ca2+]i on the condition without treating with inhibitor of Na+-Ca2+exchanger,ΔF[Ca2+]i was 363±21 in ADS group andΔF[Ca2+]i was 237±20 in control group after treatment. When compared with before treatment, there was no significant difference in both groups (P>0.05). Conclusions The increase of intracellular Ca2+induced by estrogen at EMI smooth muscle cells in adenomyosis patients was mostly from the release of arcoplasmic reticulum, and also from the Ca2+influx controlled by L-type calcium channel. The increase of Ca2+inducing abnormal contraction of EMI muscle may have relationship with the development of adenomyosis.