A LIF/Nanog axis is revealed in T lymphocytes that lack MARCH-7, a RINGv E3 ligase that regulates the LIF-receptor

Association of MARCH7 with tumor progression and T-cell infiltration in esophageal cancer

MARCH7 is an E3 ubiquitin ligase known to regulate neuronal development,T-cell proliferation, and cell and tissue differentiation. But, the altered expression of MARCH7 has been observed in various malignancies. Herein, the cellular localization and role of MARCH7 have been elucidated in esophageal squamous cell carcinoma (ESCC), the information regarding which is currently limited. To check the expression of MARCH7 and its correlation with immune cells infiltration in ESCC, immunohistochemical analysis was performed. RNAi approach was used to investigate the role of MARCH7 in esophageal cancer cells. Interestingly, we found a significantly higher expression of MARCH7 protein in 84% of ESCC tissues than in distant matched non-malignant tissues (p ≤ 0.001). In addition to this, immunohistochemistry results have shown a negative correlation between MARCH7 protein expression and tumor-infiltrating immune cells such as CD8 + T cells (r = - 0.633, p = 0.001) and PD1 + T cells (r = - 0.560, p = 0.005). Furthermore, MARCH7 silencing inhibited the ESCC cell growth and reduced the clonogenic and invasion/migration potential of ESCC cells. MARCH7 silencing also significantly increased E-cadherin protein levels in ESCC cells relative to those in negative control cells (p < 0.05). Thus, MARCH7 is oncogenic and might have a possible role in esophageal carcinogenesis. Moreover, E-cadherin may be a downstream target of MARCH7 in ESCC.

LncRNA-412.25 activates the LIF/STAT3 signaling pathway in ovarian granulosa cells of Hu sheep by sponging miR-346

Although long non-coding RNAs (lncRNAs) are reported to regulate follicular development and reproductive disease pathogenesis, the underlying mechanisms have not been elucidated. In this study, lncRNA expression profiling of different-sized healthy follicles from Hu sheep with different prolificacy revealed 50 613 lncRNAs. Numerous lncRNAs were differentially expressed among different comparison groups. This study characterized one novel transcript, lncRNA-412.25 (from healthy follicles with a diameter of >5 mm), which was predominantly expressed in the high prolificacy group and localized to the cytoplasm of granulosa cells (GCs). LncRNA-412.25 knockdown promoted and inhibited Hu sheep GC apoptosis and proliferation, respectively. Interestingly, lncRNA-412.25 could directly bind to miR-346, which can target the gene of leukemia inhibitory factor (LIF). Knockdown of lncRNA-412.25 promoted GC apoptosis by downregulating LIF expression, where this effect was attenuated by miR-346. Moreover, the miR-346 inhibitor mitigated the lncRNA-412.25 knockdown-induced downregulation of phosphorylated protein of signal transducer and activator of transcription 3 (STAT3), which was validated using immunofluorescence analysis. Our results demonstrated that lncRNA-412.25 regulates GC proliferation and apoptosis in Hu sheep by binding to miR-346 and then activating the LIF/STAT3 pathway. These findings provide novel insights into the mechanisms underlying prolificacy in sheep.

miR-27b-3p/MARCH7 regulates invasion and metastasis of endometrial cancer cells through Snail-mediated pathway

Ubiquitin E3 ligase membrane-associated RING-CH-type finger 7 (MARCH7), also known as axotrophin, was originally identified in mouse embryonic stem cells. MARCH7 is involved in T-cell proliferation, neuronal development, and the immune system. However, its role in endometrial cancer (EC) remains unclear. This study aimed to investigate the role of MARCH7 in EC. Quantitative polymerase chain reaction, immunohistochemistry, and western blot analysis were used to examine the expression of MARCH7, E-cadherin, Snail, and Vimentin in EC cell lines or clinical specimens. The role of MARCH7 in maintaining EC cell malignant phenotype was determined by transwell assay and using xenograft tumor model. Dual-luciferase reporter gene assay was performed to determine whether MARCH7 is an authentic target of miR-27b-3p. Our data showed that the expression level of MARCH7 in EC tissues was higher than that in normal endometrium tissues. The level of MARCH7 was positively associated with that of Snail and Vimentin, clinical stage, and histological grade, while negatively associated with that of E-cadherin. Knockdown of MARCH7 inhibited the invasion and metastasis of EC cells in vitro and in vivo. The opposite effect was observed after overexpressing MARCH7. MARCH7 promoted invasion and metastasis of EC cells via the Snail-mediated pathway. Furthermore, MARCH7 was demonstrated to be an authentic target of miR-27b-3p, and miR-27b-3p decreased the stimulus effect induced by MARCH7. These data indicate that MARCH7 may be an oncogenic factor and a therapeutic target for EC. miR-27b-3p/MARCH7 may also regulate EC cell invasion and metastasis via the Snail-mediated pathway.

A novel ubiquitin-protein ligase E3 functions as a modulator of immune response against lipopolysaccharide in Pacific oyster, Crassostrea gigas

Ubiquitination is an important post-translational protein modification and plays a crucial role in various processes such as cell cycle, signal transduction, and transcriptional regulation. In the present study, a novel ubiquitin (Ub)-protein ligase E3 (designed as CgE3Rv1) was identified from Crassostrea gigas, and its ubiquitination regulation in the immune response against lipopolysaccharide (LPS) stimulation was investigated. The open reading frame of CgE3Rv1 gene was of 1455 bp encoding a polypeptide of 484 amino acids with the predicted molecular mass of 54.89 kDa. There were two transmembrane regions and a RING-variant (RINGv) domain identified in CgE3Rv1. CgE3Rv1 shared similar C4HC3 zinc-finger-like motif with those RINGv domain Ub-protein ligases E3s identified from vertebrates and invertebrates, and it was closely clustered with the membrane-associated RING-CH2 (MARCH2) Ub-protein ligases E3s in the phylogenetic tree. The mRNA transcript of CgE3Rv1 was highest expressed in gonads and hemolymph (p < 0.05), and its mRNA expression level in hemocytes was significantly increased at 6 h (p < 0.01) after the stimulation of LPS, while the up-regulated mRNA expression was significantly decreased (p < 0.01) after acetylcholine stimulation. No significant changes of CgE3Rv1 expression were observed after peptidoglycan or mannan stimulation. Immunohistochemistry and in situ hybridization assays revealed that CgE3Rv1 protein and mRNA were dominantly distributed in the gonad. In the hemocytes, CgE3Rv1 was mainly located around the nucleus, and slightly distributed in the cytoplasm and on the cell membrane. Recombinant CgE3Rv1 RINGv domain protein (rCgE3Rv1-RINGv) was confirmed to activate the Ub reaction system in vitro with the aid of Ub-activating enzyme E1 and Ub-conjugating enzyme E2. These results demonstrated that CgE3Rv1 was an Ub-protein ligase E3, which was involved in the immune response against LPS and the interaction with cell surface signal molecules of neuroendocrine-immune system in oysters.

Rapamycin induces pluripotent genes associated with avoidance of replicative senescence

Primary rodent cells undergo replicative senescence, independent from telomere shortening. We have recently shown that treatment with rapamycin during passages 3-7 suppressed replicative senescence in rat embryonic fibroblasts (REFs), which otherwise occurred by 10-14 passages. Here, we further investigated rapamycin-primed cells for an extended number of passages. Rapamycin-primed cells continued to proliferate without accumulation of senescent markers. Importantly, these cells retained the ability to undergo serum starvation- and etoposide-induced cell cycle arrest. The p53/p21 pathway was functional. This indicates that rapamycin did not cause either transformation or loss of cell cycle checkpoints. We found that rapamycin activated transcription of pluripotent genes, oct-4, sox-2, nanog, as well as further upregulated telomerase (tert) gene. The rapamycin-derived cells have mostly non-rearranged, near-normal karyotype. Still, when cultivated for a higher number of passages, these cells acquired a chromosomal marker within the chromosome 3. We conclude that suppression mTORC1 activity may prevent replicative senescence without transformation of rodent cells.

Targeted nanotherapy for induction of therapeutic immune responses

Nanotechnology permits the design of therapeutic devices with defined structure and molecular composition. Modular designs employing surface-bound ligands provide specific homing devices for loaded cargo, and biocompatible and biodegradable constructs provide surrogate temporary microenvironments. We first present a case for developing 'smart' modular constructs as immunogenic vaccines to prime immune memory against specific pathogens where current vaccines fail. Second, we argue that nanotherapeutic intervention can harness pivotal molecular pathways recently discovered to regulate lineage development between pathogenic TH17 cells associated with autoimmune disease, versus tolerogenic regulatory T cells (Treg). Underpinned by molecular mechanisms that enable exquisitely specific responses in adaptive immunity, targeted nanodevices designed to stimulate either immune aggression or immune tolerance signify the birth of a new era in therapeutics.

The unfolded protein response (UPR)-activated transcription factor X-box-binding protein 1 (XBP1) induces microRNA-346 expression that targets the human antigen peptide transporter 1 (TAP1) mRNA and governs immune regulatory genes

To identify endoplasmic reticulum (ER) stress-induced microRNAs (miRNA) that govern ER protein influx during the adaptive phase of unfolded protein response, we performed miRNA microarray profiling and analysis in human airway epithelial cells following ER stress induction using proteasome inhibition or tunicamycin treatment. We identified miR-346 as the most significantly induced miRNA by both classic stressors. miR-346 is encoded within an intron of the glutamate receptor ionotropic delta-1 gene (GRID1), but its ER stress-associated expression is independent of GRID1. We demonstrated that the spliced X-box-binding protein-1 (sXBP1) is necessary and sufficient for ER stress-associated miR-346 induction, revealing a novel role for this unfolded protein response-activated transcription factor. In mRNA profiling arrays, we identified 21 mRNAs that were reduced by both ER stress and miR-346. The target genes of miR-346 regulate immune responses and include the major histocompatibility complex (MHC) class I gene products, interferon-induced genes, and the ER antigen peptide transporter 1 (TAP1). Although most of the repressed mRNAs appear to be indirect targets because they lack specific seeding sites for miR-346, we demonstrate that the human TAP1 mRNA is a direct target of miR-346. The human TAP1 mRNA 3'-UTR contains a 6-mer canonical seeding site for miR-346. Importantly, the ER stress-associated reduction in human TAP1 mRNA and protein levels could be reversed with an miR-346 antagomir. Because TAP function is necessary for proper MHC class I-associated antigen presentation, our results provide a novel mechanistic explanation for reduced MHC class I-associated antigen presentation that was observed during ER stress.

LIF in the regulation of T-cell fate and as a potential therapeutic

At the heart of lineage commitment within the adaptive immune response is the intrinsic genetic plasticity of the naive peripheral T lymphocyte (T cell). Primary activation by presentation of cognate antigen is coupled to rapid T-cell cycling and progressive epigenetic changes that guide the cell down distinct T-cell lineages, either effector (Th1, Th2, Th17) or tolerogenic (Treg). Fate choice is influenced both by strength of the priming activation signal and by cues from the micro-environment that are integrated with lineage-specific gene expression profiles, eventually becoming hard-wired in the fully differentiated cell. The micro-environmental cues include cytokines, and the discovery that leukaemia inhibitory factor (LIF) and interleukin (IL)-6 counter-regulate development of the Treg and Th17 lineages places LIF within the core regulatory circuitry of T cells. I first summarise current understanding of LIF and the LIF receptor in the context of T cells. Next, the central relevance of the LIF/IL-6 axis in immune-mediated disease is set in the context of (i) a new nano-therapeutic approach for targeted delivery of LIF and (ii) MARCH-7, a novel E3-ligase discovered to have a central mechanistic role in LIF-mediated T-cell biology, functioning as a rheostat-type regulator of endogenous LIF-signalling.