Among a great variety of cell surface receptors, the largest superfamily is G protein-coupled receptors (GPCRs), also known as seven-transmembrane domain receptors. GPCRs can modulate diverse signal-transduction pathways through G protein-dependent or independent pathways which involve β-arrestins, G protein receptor kinases (GRKs), ion channels, or Src kinases under physiological and pathological conditions. Recent studies have revealed the crucial role of GPCRs in the tumorigenesis and the development of cancer metastasis. We will sum up the functions of GPCRs—particularly those coupled to chemokines, prostaglandin, lysophosphatidic acid, endothelin, catecholamine, and angiotensin—in the proliferation, invasion, metastasis, and angiogenesis of hepatoma cells and the development of hepatocellular carcinoma (HCC) in this review. We also highlight the potential avenues of GPCR-based therapeutics for HCC.

BackgroundPrimary Sjögren’s syndrome (pSS) is a systemic autoimmune disease characterised by aberrant B cell hyperactivation, whose mechanism is partially understood.MethodsWe performed whole transcriptome sequencing of B cells from three pSS patients and three matched healthy controls (HC). Differentially expression genes (DEGs) were confirmed with B cells from 40 pSS patients and 40 HC by quantitative PCR and western blot. We measured the proliferation potential and immunoglobulins production of siRNA-transfected or plasmid-transfected B cells stimulated with cytosine-phosphate-guanine (CpG) or anti-IgM. We also explored Toll-like receptor 9 (TLR9) signalling to reveal the potential mechanism of B cell hyperactivation in pSS.ResultsWe identified 77 upregulated and 32 downregulated DEGs in pSS B cells. We confirmed that epithelial stromal interaction (EPST1) expression in pSS B cells was significantly higher than that from HCs. EPSTI1-silencing B cells stimulated with CpG were less proliferated and produced lower level of IgG and IgM comparing with control B cells. EPSTI1-silencing B cells expressed lower level of p-p65 and higher level of IκBα, and B cells with overexpressed EPSTI1 showed higher level of p-p65 and lower level of IκBα. Finally, IκBα degradation inhibitor Dehydrocostus Lactone treatment attenuated p65 phosphorylation promoted by EPSTI1.ConclusionElevated EPSTI1 expression in pSS B cells promoted TLR9 signalling activation and contributed to the abnormal B cell activation, which was promoted by facilitating p65 phosphorylation and activation of NF-κB signalling via promoting IκBα degradation. EPSTI1 might be implicated in pSS pathogenesis and was a potential therapeutic target of pSS.

G protein-coupled receptor kinases (GRKs) constitute seven subtypes of serine/threonine protein kinases that specifically recognize and phosphorylate agonist-activated G protein-coupled receptors (GPCRs), thereby terminating the GPCRs-mediated signal transduction pathway. Recent research shows that GRKs also interact with non-GPCRs and participate in signal transduction in non-phosphorylated manner. Besides, GRKs activity can be regulated by multiple factors. Changes in GRKs expression have featured prominently in various tumor pathologies, and they are associated with angiogenesis, proliferation, migration, and invasion of malignant tumors. As a result, GRKs have been intensively studied as potential therapeutic targets. Herein, we review evolving understanding of the function of GRKs, the regulation of GRKs activity and the role of GRKs in human malignant tumor pathophysiology.

No abstract

Objectives: To explore the potential role of CD3+CD8+CD161high TCRVα7.2+ mucosal-associated invariant T (MAIT) cells in the pathogenesis of primary biliary cholangitis (PBC).Methods: We enrolled 55 patients with PBC, 69 healthy controls (HCs), and 8 patients with hepatic hemangioma. Circulating MAIT cells and their chemokine receptor profiles and cytokine production were quantified using flow cytometry. Liver-resident MAIT cells were examined by immunofluorescence staining. CXCL12-mediated chemotaxis of MAIT cells was measured using a transwell migration assay. Plasma interleukin (IL)-18 was measured using ELISA, and cytokine production in IL-18-stimulated MAIT cells was detected using flow cytometry.Result: Peripheral MAIT cells were found to be significantly lower in patients with PBC (3.0 ± 3.2% vs. 9.4 ± 8.0%, p < 0.01) and negatively correlated with alkaline phosphatase (ALP) levels (r = −0.3209, p < 0.05). Liver immunofluorescence staining suggested that MAIT cells might accumulate in PBC liver. MAIT cells from patients with PBC expressed higher levels of CXCR4 (84.8 ± 18.0% vs. 58.7 ± 11.4%, p < 0.01), and the expression of CXCL12 was higher in PBC liver. CXCL12 promoted MAIT cell chemotaxis (70.4 ± 6.8% vs. 52.2 ± 3.5%, p < 0.01), which was attenuated by CXCR4 antagonist. MAIT cells from PBC produced significantly more interferon-γ (IFN-γ) (88.3 ± 4.2% vs. 64.2 ± 10.1%, p < 0.01), tumor necrosis factor-α (TNF-α) (93.0 ± 1.1% vs. 80.1 ± 5.3%, p < 0.01), Granzyme B (89.3 ± 3.3% vs. 72.1 ± 7.0%, p < 0.01), and perforin (46.8 ± 6.6% vs. 34.8 ± 7.7%, p < 0.05). MAIT cells from PBC expressed higher levels of IL18-Rα (83.8 ± 10.2% vs. 58.3 ± 8.7%, p < 0.01). Plasma IL-18 was more abundant in patients with PBC (286.8 ± 75.7 pg/ml vs. 132.9 ± 78.1 pg/ml, p < 0.01). IL-18 promoted IFN-γ production in MAIT cells (74.9 ± 6.6% vs. 54.7 ± 6.7%, p < 0.01), which was partially attenuated by blocking IL-18R (68.6 ± 8.3% vs. 43.5 ± 4.2%, p < 0.01).Conclusion: Mucosal-associated invariant T cells from patients with PBC accumulated in the liver via CXCL12-CXCR4-mediated chemotaxis, produced pro-inflammatory cytokines, and contributed to portal inflammation, which was potentially mediated by elevated IL-18. Targeting MAIT cells might be a therapeutic approach for PBC.

The tris-alkyl complex Y(CH 2 SiMe 3 ) 3 (THF) 2 reacts with 1,2,3-trimethyl-1H-cyclopenta[l]phenanthrene (PCp*H) to give (PCp*)Y(CH 2 SiMe 3 ) 2 (THF) (1), characterized structurally by X-ray crystallography. VT NMR spectra of 1 reveal a dynamic equilibrium between the THF-free and mono(THF) solvate in solution. Complex 1 undergoes substitution of THF by 2,2′-bipyridine (bipy) to give (PCp*)-Y(CH 2 SiMe 3 ) 2 (bipy) (2); the latter complex does not undergo ligand exchange in solution. Insertion reactions of 1 with CO 2 , Me 3 SiNCO, and Me 2 CHNdCdNCHMe 2 afford 5). Reaction of 1 with 2 equiv of Me 3 SiCCH affords a terminal bis(acetylide) (PCp*)Y(CCSiMe 3 ) 2 (THF) (6) in solution; however, X-ray analysis of crystals obtained from a solution of 6 shows that it dimerizes to {[(PCp*)Y(CCSiMe 3 )(THF)] 2 (µ-CCSiMe 3 ) 2 } (7). A toluene solution of complex 1 and 1 equiv of [Ph 3 C] + [B(C 6 F 5 ) 4 ]shows modest catalytic activity for the polymerization of ethylene at room temperature (20 kg mol -1 h -1 bar -1 ).

The first lanthanoid complexes containing delocalized phenalenide anions are reported and the rapid migration of the eta(3)-bonded metal centre between the three rings of the pi-system is the first report of a degenerate haptotropic rearrangement in organolanthanoid chemistry.

Hepatic fibrosis is a disease characterized by excessive deposition of extracellular matrix (ECM) in the liver. Activation of hepatic stellate cells (HSCs) is responsible for most of ECM production. Oxidative stress and reactive oxygen species (ROS) may be important factors leading to liver fibrosis. NADPH oxidase 4 (NOX4) is the main source of ROS in hepatic fibrosis, but the mechanism by which NOX4 regulates oxidative stress is not fully understood. β-Arrestin2 is a multifunctional scaffold protein that regulates receptor endocytosis, signaling and trafficking. In this study, we investigated whether β-arrestin2 regulated oxidative stress in hepatic fibrosis. Both β-arrestin2 knockout (Arrb2 KO) mice and wild-type mice were intraperitoneally injected with carbon tetrachloride (CCl 4 ) to induce hepatic fibrosis. Arrb2 KO mice showed significantly attenuated liver fibrosis, decreased ROS levels and NOX4 expression, and reduced collagen levels in their livers. In vitro, NOX4 knockdown significantly inhibited ROS production, and decreased expression of alpha-smooth muscle actin in angiotensin II-stimulated human HSC cell line LX-2. Through overexpression or depletion of β-arrestin2 in LX-2 cells, we revealed that decreased β-arrestin2 inhibited ROS levels and NOX4 expression, and reduced collagen production; it also inhibited activation of ERK and JNK signaling pathways. These results demonstrate that β-arrestin2 deficiency protects against liver fibrosis by downregulating ROS production through NOX4. This effect appears to be mediated by ERK and JNK signaling pathways. Thus, targeted inhibition of β-arrestin2 might reduce oxidative stress and inhibit the progression of liver fibrosis.