Compared with preoperative gastric emptying, early postoperative gastric emptying for liquid food after oesophagectomy is significantly faster. Postoperative early oral feeding in patients with thoracolaparoscopic oesophagectomy is feasible and safe.
Background and Aims Progressive familial intrahepatic cholestasis (PFIC) 6 has been associated with missense but not biallelic nonsense or frameshift mutations in MYO5B , encoding the motor protein myosin Vb (myoVb). This genotype‐phenotype correlation and the mechanism through which MYO5B mutations give rise to PFIC are not understood. The aim of this study was to determine whether the loss of myoVb or expression of patient‐specific myoVb mutants can be causally related to defects in canalicular protein localization and, if so, through which mechanism. Approach and Results We demonstrate that the cholestasis‐associated substitution of the proline at amino acid position 600 in the myoVb protein to a leucine (P660L) caused the intracellular accumulation of bile canalicular proteins in vesicular compartments. Remarkably, the knockout of MYO5B in vitro and in vivo produced no canalicular localization defects. In contrast, the expression of myoVb mutants consisting of only the tail domain phenocopied the effects of the Myo5b‐P660L mutation. Using additional myoVb and rab11a mutants, we demonstrate that motor domain‐deficient myoVb inhibited the formation of specialized apical recycling endosomes and that its disrupting effect on the localization of canalicular proteins was dependent on its interaction with active rab11a and occurred at the trans ‐Golgi Network/recycling endosome interface. Conclusions Our results reveal a mechanism through which MYO5B motor domain mutations can cause the mislocalization of canalicular proteins in hepatocytes which, unexpectedly, does not involve myoVb loss‐of‐function but, as we propose, a rab11a‐mediated gain‐of‐toxic function. The results explain why biallelic MYO5B mutations that affect the motor domain but not those that eliminate myoVb expression are associated with PFIC6.
Abstract. The programmed death-1 (PD-1)/programmed death-ligands (PD-Ls) signal pathway has been implicated as a potential immune escape mechanism in several human cancers. However, the studies of PD-1/PD-Ls pathway in esophageal squamous cell carcinoma (ECSS) are not yet sufficient. The current study investigated the expression of PD-L1, PD-L2 and PD-1 in ESCC tissues. The correlations between the expression of these proteins and clinical histopathological parameters were analyzed. Then the stable transfected Ec109 cell lines overexpressing PD-L1/PD-L2 were established by plasmid transfection successfully. Ec109 and CD8 + T cells were co-cultured to analyze the effects of PD-1/PD-Ls signal pathway on the function of CD8 + T cells including proliferation, apoptosis and interferon-γ production. We found that PD-L1-positive patients had significantly poorer prognosis than the negative patients, while their prognosis was not related to PD-L2 expression. The count of PD-1 + TILs (tumor-infiltrating lymphocytes) was negatively correlated with both PD-L1 and PD-L2 expression. In functional studies, we found that PD-1/PD-Ls signal pathway was able to downregulate the function of CD8 + T lymphocyte and its function could be restored by blocking the signal pathway. This indicates that PD-1/PD-Ls may prevent effective antitumor immunity, which provides important evidence to delineate the cellular immune deficiency mechanism in ESCC. Therefore, PD-1/PD-Ls are predicted to become novel targets for ESCC immunotherapy.
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