Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific liver disease. The maternal symptoms are characterized by skin pruritus and elevated bile acids, causing several adverse outcomes for fetuses, including an increased risk of preterm birth, meconium-stained amniotic fluid, neonatal depression, respiratory distress syndrome, and stillbirth. Genetic, hormonal, immunological, and environmental factors contribute to the pathogenesis of ICP, and the estrogen-bile acid axis is thought to play a dominant role. The advances in the past 10 years uncover more details of this axis. Moreover, dysregulation of extracellular matrix and oxygen supply, organelle dysfunction, and epigenetic changes are also found to cause ICP, illuminating more potential drug targets for interfering with. Here, we summarize the molecular pathogenesis of ICP with an emphasis on the advancement in the past 10 years, aiming to give an updated full view of this field.

Enhanced migration potential is a common characteristic of cancer cells induced by mechanisms that are incompletely defined. The present study was designed to investigate relationship of a new discovered cytoskeleton regulator MICAL‐L2 and the endogenous epidermal growth factor receptor (EGFR) signalling pathways in gastric cancer cell migration. Increased expression of MICAL‐L2 in gastric cancer cells up‐regulated EGFR protein level, accompanied by the increase of cell migration, whereas silencing MICAL‐L2 down‐regulated EGFR and inhibited cell migration. Expression of MICAL‐L2 was also shown positively correlated with the activation of HSP27/cytoskeleton and HSP27/β‐catenin signalling pathways that provide key mechanisms controlling cell migration. The up‐regulating effect of MICAL‐L2 on EGFR is mediated through a transcription‐independent mechanism that involves inhibiting EGFR protein degradation in lysosome. Further analysis indicated that Cdc42 activation contributed in maintaining the effect of MICAL‐L2 on EGFR stability. Furthermore analysis of clinic specimens revealed increased expression of MICAL‐L2 in carcinoma tissues and a positive correlation between MICAL‐L2 and EGFR expression levels. The above results indicate that MICAL‐L2 potentiates gastric cell migration via inhibiting EGFR degradation in lysosome via a Cdc42‐dependent manner that leads to the activation of EGFR/HSP27 signalling pathways.

Background and Purpose— Stroke is a major public health concern worldwide. Although clinical treatments have improved in the acute period after stroke, long-term therapeutics remain limited to physical rehabilitation in the delayed phase. This study is aimed to determine whether nNOS (neuronal NO synthase)-CAPON (carboxy-terminal postsynaptic density-95/discs large/zona occludens-1 ligand of nNOS) interaction may serve as a new therapeutic target in the delayed phase for stroke recovery. Methods— Photothrombotic stroke and transient middle cerebral artery occlusion were induced in mice. Adeno-associated virus (AAV)-cytomegalovirus (CMV)-CAPON-125C-GFP (green fluorescent protein)-3Flag and the other 2 drugs (Tat-CAPON-12C and ZLc-002) were microinjected into the peri-infarct cortex immediately and 4 to 10 days after photothrombotic stroke, respectively. ZLc-002 was also systemically injected 4 to 10 days after transient middle cerebral artery occlusion. Grid-walking task and cylinder task were conducted to assess motor function. Western blotting, immunohistochemistry, Golgi staining, and electrophysiology recordings were performed to uncover the mechanisms. Results— Stroke increased nNOS-CAPON association in the peri-infarct cortex in the delayed period. Inhibiting the ischemia-induced nNOS-CAPON association substantially decreased the number of foot faults in the grid-walking task and forelimb asymmetry in the cylinder task, suggesting the promotion of functional recovery from stroke. Moreover, dissociating nNOS-CAPON significantly facilitated dendritic remodeling and synaptic transmission, indicated by increased dendritic spine density, dendritic branching, and length and miniature excitatory postsynaptic current frequency but did not affect stroke-elicited neuronal loss, infarct size, or cerebral edema, suggesting that nNOS-CAPON interaction may function via regulating structural neuroplasticity, rather than neuroprotection. Furthermore, ZLc-002 reversed the transient middle cerebral artery occlusion–induced impairment of motor function. Conclusions— Our results reveal that nNOS-CAPON coupling can serve as a novel pharmacological target for functional restoration after stroke.

As a result of its spatial confinement in cardiomyocytes, neuronal nitric oxide synthase (nNOS) is thought to regulate mitochondrial and sarcoplasmic reticulum (SR) function by maintaining nitroso-redox balance and Ca2+ cycling. Thus, we hypothesize that ischemic postconditioning (IPostC) protects hearts against ischemic/reperfusion (I/R) injury through an nNOS-mediated pathway. Isolated mouse hearts were subjected to I/R injury in a Langendorff apparatus, H9C2 cells and primary neonatal rat cardiomyocytes were subjected to hypoxia/reoxygenation (H/R) in vitro. IPostC, compared with I/R, decreased infarct size and improved cardiac function, and the selective nNOS inhibitors abolished these effects. IPostC recovered nNOS activity and arginase expression. IPostC also increased AMP kinase (AMPK) phosphorylation and alleviated oxidative stress, and nNOS and AMPK inhibition abolished these effects. IPostC increased nitrotyrosine production in the cytosol but decreased it in mitochondria. Enhanced phospholamban (PLB) phosphorylation, normalized SR function and decreased Ca2+ overload were observed following the recovery of nNOS activity, and nNOS inhibition abolished these effects. Similar effects of IPostC were demonstrated in cardiomyocytes in vitro. IPostC decreased oxidative stress partially by regulating uncoupled nNOS and the nNOS/AMPK/peroxisome proliferator-activated receptor gamma coactivator 1 alpha/superoxide dismutase axis, and improved SR function through increasing SR Ca2+ load. These results suggest that IPostC protected hearts against I/R injury via an nNOS-mediated pathway.

Objectives: MICAL-L2, a member of the molecules interacting with the CasL (MICAL) family, was reported to be highly expressed in several types of cancers, however, the roles of MICAL-L2 in NSCLC pathogenesis remain to be explored. This study is designed to clarify the mechanisms by which MICAL-L2 participates in NSCLC cell proliferation.Materials and Methods: The expression levels of MICAL-L2 in human lung cancer samples were assessed by immunohistochemical staining. Cells were transfected with siRNA or plasmids to regulate MICAL-L2 expression. Cell proliferation was measured by EdU staining and CCK-8 assays. MICAL-L2 and phosphorylated/total c-Myc expression were examined by Western blotting analysis. Interaction between MICAL-L2 and c-Myc was assessed by immunofluorescence staining, Western blotting and co-immunoprecipitation assays. Western blotting, polyubiquitylation detection and protein stability assays were used to assess whether MICAL-L2 exerts its oncogenic effect via c-Myc.Results: We found that MICAL-L2 was highly expressed in human NSCLC. While overexpressing MICAL-L2 increased NSCLC cell proliferation, MICAL-L2 depletion decreased the proliferation of NSCLC cells, an effect that was linked to cell cycle arrest. MICAL-L2 physically interacted with the c-Myc protein and functioned to maintain nuclear c-Myc levels and prolonged its half-life. Knockdown of MICAL-L2 expression led to decreased c-Myc protein stability through accelerating polyubiquitylation of c-Myc and gave rise to c-Myc degradation. We further found that MICAL-L2 deubiquitinated c-Myc and blocked its degradation, presumably by inhibiting c-Myc phosphorylation at threonine residue 58.Conclusions: These results indicate that MICAL-L2 is a key regulator of c-Myc deubiquitination and stability in the nucleus, and this activity may be involved in promoting NSCLC cell proliferation.