Immunoglobulin G (IgG) Fc receptors play a critical role in linking IgG antibody-mediated immune responses with cellular effector functions. A high resolution map of the binding site on human IgG1 for human Fc␥RI, Fc␥RIIA, Fc␥RIIB, Fc␥RIIIA, and FcRn receptors has been determined. A common set of IgG1 residues is involved in binding to all Fc␥R; Fc␥RII and Fc␥RIII also utilize residues outside this common set. In addition to residues which, when altered, abrogated binding to one or more of the receptors, several residues were found that improved binding only to specific receptors or simultaneously improved binding to one type of receptor and reduced binding to another type. Select IgG1 variants with improved binding to Fc␥RIIIA exhibited up to 100% enhancement in antibody-dependent cell cytotoxicity using human effector cells; these variants included changes at residues not found at the binding interface in the IgG/Fc␥RIIIA co-crystal structure (Sondermann, P., Huber, R., Oosthuizen, V., and Jacob, U. (2000) Nature 406, 267-273). These engineered antibodies may have important implications for improving antibody therapeutic efficacy.

Peripheral infusion of allogeneic bone marrow-derived MSCs is safe and convenient for patients with HBV-related ACLF and significantly increases the 24-week survival rate by improving liver function and decreasing the incidence of severe infections. (Hepatology 2017;66:209-219).

Highlights: Patients with coronavirus disease 2019 (COVID-19) had altered inflammatory markers. High sensitivity C-reactive protein-(pre)albumin ratios positively correlated with severe COVID-19. Prognostic nutritional index negatively correlated with risk of severe COVID-19. Nomogram combining the three factors reliably predicted the progression of COVID-19. High sensitivity C-reactive protein-prealbumin and -albumin ratios helped estimate duration of hospitalization.

Dipeptidyl peptidase IV (DP-IV) is a cell surface serine dipeptidase that is involved in the regulation of the incretin hormones, glucagon-like peptide (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). There is accumulating evidence that other members of the glucagon family of peptides are also endogenous substrates for this enzyme. To identify candidate substrates for DP-IV, a mass spectrometry-based protease assay was developed that measures cleavage efficiencies (k cat /K m ) of polypeptides in a mixture, using only a few picomoles of each substrate and physiological amounts of enzyme in a single kinetic experiment. Oxyntomodulin and the growth hormone-(1-43) fragment were identified as new candidate in vivo substrates. Pituitary adenylate cyclase-activating polypeptide-(1-38) (PACAP38), a critical mediator of lipid and carbohydrate metabolism, was also determined to be efficiently processed by DP-IV in vitro. The catabolism of exogenously administered PACAP38 in wild type and DP-IVdeficient C57Bl/6 mice was monitored by tandem mass spectrometry. Animals lacking DP-IV exhibited a significantly slower clearance of the circulating peptide with virtually complete suppression of the inactive DP-IV metabolite, PACAP-(3-38). These in vivo results suggest that DP-IV plays a major role in the degradation of circulating PACAP38.

ObjectiveThe goal of the present study was to investigate the potential correlation between the expression level of upregulator of cell proliferation (URGCP/URG4) and the prognosis of hepatocellular carcinoma (HCC), and to examine the biological function of URGCP/URG4 in the progression of HCC, to better understand its underlying molecular mechanism in hepatic tumorigenesis.DesignURGCP/URG4 expression was analyzed in 15 HCC cell lines, in 278 archived paraffin-embedded HCC sections, and in 10 pairs of fresh HCC tumor and para-tumor non-cancerous tissues using immunohistochemistry (IHC) and Western blotting analysis (WB). The effect of URGCP/URG4 on cell proliferation and tumorigenesis was examined in vitro and in vivo. WB and luciferase reporter analyses were performed to identify the effects of URGCP/URG4-overexpression or -knockdown on expression of cell cycle regulators and transcriptional activity of FOXO3a.ResultsIHC results revealed an upregulation of URGCP/URG4 in all HCC cell lines and fresh HCC samples as compared with normal liver cells and para-tumor tissues, respectively. URGCP/URG4 was also expressed at a high level in 122 of the 278 (43.8%) archived HCC specimens. The expression level of URGCP/URG4 was significantly correlated with clinical staging and poor patient survival of HCC in the study cohort, and in various clinical subgroups. Strikingly, ectopic expression of URGCP/URG4 induced proliferation and anchorage-independent growth of HCC cells, while silencing of URGCP/URG4 had the opposite effect. Furthermore, URGCP/URG4 overexpression in HCC cells increased cellular entry into the G1/S transitional phase, associated with downregulation of p27Kip1 and p21Cip1 and upregulation of cyclin D1. These effects were accompanied by enhanced Akt activity and reduced FOXO3a transcriptional activity.ConclusionsURGCP/URG4 plays an important role in promoting proliferation and tumorigenesis of HCC and may represent a novel prognostic biomarker and therapeutic target for this disease.