Effect of IgG fragments in IVIG(pH4)on phagocytosis of sensitized erythrocytes by macrophage / 中国输血杂志

【Objective】 To research the effect of the Fc, Fab and F(ab′)2 fragments of immunoglobulin G, the main components of Human Immunoglobulin(pH4) for Intravenous Injection(IVIG), on the phagocytic function of macrophages derived from THP-1 cells. 【Methods】 First of all, IVIG was digested with papain and pepsin to obtain Fc, Fab and F(ab′)2, and these components were then identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Afterwards, propylene glycol monomethyl ether acetate (PMA) was used to induce THP-1 cells to differentiate into M0 macrophages. Finally, the sensitized erythrocytes were labeled with carboxy fluorescein succinimidyl ester (CFSE), and the effect of the above components on the phagocytic ability of M0 macrophages to engulf sensitized erythrocytes was detected by flow cytometry. 【Results】 The identification results of SDS-PAGE showed that the prepared IgG fragments met the requirements of subsequent experiments. Flow cytometry performs showed that the phagocytosis model of M0 macrophages had been successfully established. When the concentration of Fc increased from 0.1μg/ mL to 10μg/ mL, the phagocytosis rate of erythrocytes sensitized by M0 macrophages decreased from (24.21±0.58) % to (12.27±0.19) %. When the concentration of IVIG protein increased from 0.1 μg/ml to 10 μg/ml, the phagocytosis rate decreased from (20.57±0.39) % to (0.20±0.03) %. Meanwhile, at the same protein concentration (10 μg/ml), the inhibitory effect of Fc on phagocytosis was only half that of IVIG. In addition, Fab, F(ab′)2, and human serum albumin could not inhibit phagocytosis of M0 macrophages. 【Conclusion】 IVIG can effectively inhibit the phagocytosis of THP-1 derived M0 macrophages, which is mainly dependent on the Fc, but not related to the Fab of IgG and F (ab′)2.

Lineage reprogramming of fibroblasts into induced cardiac progenitor cells by CRISPR/Cas9-based transcriptional activators

Overexpression of exogenous lineage-determining factors succeeds in directly reprogramming fibroblasts to various cell types. Several studies have reported reprogramming of fibroblasts into induced cardiac progenitor cells (iCPCs). CRISPR/Cas9-mediated gene activation is a potential approach for cellular reprogramming due to its high precision and multiplexing capacity. Here we show lineage reprogramming to iCPCs through a dead Cas9 (dCas9)-based transcription activation system. Targeted and robust activation of endogenous cardiac factors, including GATA4, HAND2, MEF2C and TBX5 (G, H, M and T; GHMT), can reprogram human fibroblasts toward iCPCs. The iCPCs show potentials to differentiate into cardiomyocytes, smooth muscle cells and endothelial cells . Addition of MEIS1 to GHMT induces cell cycle arrest in G2/M and facilitates cardiac reprogramming. Lineage reprogramming of human fibroblasts into iCPCs provides a promising cellular resource for disease modeling, drug discovery and individualized cardiac cell therapy.

DRAM1 attenuates the acute ischemic injury of cardiomyocytes via autophagy flux / 实用医学杂志

Objective To investigate the effect of DRAM1 on the acute ischemic injury of H9C2 cardiomyocytes. Methods H9C2 cardiomyocytes were treated with Oxygen-glucose deprivation (OGD) after DRAM1 adenovirus transfection. MTT assay was performed to detect cell viability and Annex V/PI staining was used to analyze the cell apoptosis. Western blot was performed to measure the expression of P62. Results DRAM1 overexpression increased the H9C2 cardiomycytes viability after OGD treatment for 12 hours. DRAM1 overexpression was attenuated, while siRNA-AD-DRAM1 exacerbated the apoptosis rate of H9C2 cardiomycytes after OGD treatment for 12 hours by Annex V/PI staining. P62 protein expression was increased in the H9C2 cardiomycytes after OGD treatment for 12 hours, which was reversed by DRAM1 overexpression. Conclusion DRAM1 may protect H9C2 cardiomycytes against OGD injury due to the improvement of the autophagy flux.