A Novel Carbamoyloxy Arylalkanoyl Arylpiperazine Compound (SKL-NP) Inhibits Hyperpolarization-Activated Cyclic Nucleotide-Gated (HCN) Channel Currents in Rat Dorsal Root Ganglion Neurons

In this study, we determined mode of action of a novel carbamoyloxy arylalkanoyl arylpiperazine compound (SKL-NP) on hyperpolarization-activated cyclic nucleotide-gated (HCN) channel currents (Ih) that plays important roles in neuropathic pain. In small or medium-sized dorsal root ganglion (DRG) neurons (<40 microm in diameter) exhibiting tonic firing and prominent Ih, SKL-NP inhibited Ih and spike firings in a concentration dependent manner (IC50=7.85 microM). SKL-NP-induced inhibition of Ih was blocked by pretreatment of pertussis toxin (PTX) and N-ethylmaleimide (NEM) as well as 8-Br-cAMP, a membrane permeable cAMP analogue. These results suggest that SKL-NP modulates Ih in indirect manner by the activation of a Gi-protein coupled receptor that decreases intracellular cAMP concentration. Taken together, SKL-NP has the inhibitory effect on HCN channel currents (I h) in DRG neurons of rats.

Autotransplantation of genetically-altered mesenchymal stem cells in treatment of complete heart block in porcine / 第二军医大学学报

Objective: To transplant the autologous mesenchymal stem cells (MSCs) carrying human hyperpolarization activated cyclic nucleoside gated channel 2 (hHCN2) gene into the His-bundle in porcine model of complete heart block (CHB), so as to assess the possibility of establishing autologous biological pacing. Methods: We constructed the recombinant adenovirus containing hHCN2 gene to transfect the porcine MSCs. After autotransplantation into the Hie-bundle in CHB model, the genetically-altered MSCs were tested for their ability to provide a stable and catecholamine-responsive heart rhythm. Histological and immunofluorescence analyses were also performed for the myocardium of the injection site. Results: Recombinant adenovirus pAd. hHCN2 was successfully constructed. Porcine MSCs were transfected by the adenovirus. After autotransplantation, transgenic MSCs significantly enhanced the heart rates in porcine CHB model compared with the control group (P < 0.01), and the cardiac rhythms in the transgenic MSC group were catecholamine responsive. Tissues obtained from the transplanted heart sites showed that the MSCs survived in the myocardium and overexpressed hHCN2 protein. Conclusion: Transplantation of autologous genetically-altered MSCs into the His-bundle in porcine CHB model can serve as a short-term catecholamine-responsive biological pacemaker.

Differentiation of rats bone marrow mesynchymal stem cells into cardiomyogenic cells with pacemaking function / 基础医学与临床

Objective To find the way of inducing the bone marrow mesynchymal stem cells(MSCs)into cardiac cells with pacemaking function in vitro.Methods Dissociate the rat MSCs and induce them with 5AZA,bFGF+EGF,HGF,SCF and lysate of the sinoatrial cells respectively.The morphological changes were observed,and the expressing of protein cTnT,connexin 43 and HCN2/4 were analyse by immunohistologic and flowcytometry techniques.The pacmaking current If were evaluted by patch clamp techniques.Results All the methods can induce the bone marrow MSCs to differentiate into cardiac cells,which expressing cardiac cell specific protein and HCN2.Cells induced by 5AZA,bFGF+EGF and SAN CMs show higher rate of HCN2 expressing(22.9%,22.3%,11%).The cells of these groups have the pacmaking current If.Conclusion Lysate of the sinoatrial cells are ideal methods of inducing the bone marrow MSCs to differentiate into cardiac cells with pacemaking function in vitro.HCN is a promising marker protein to select pacmaking cells out of the differentiated cells.