Targeting Enclysis in Liver Autoimmunity, Transplantation, Viral Infection and Cancer

Common mechanisms in pediatric acute liver failure

Acute liver failure (ALF) is a rare but potentially fatal disease in children. The etiology is multifactorial, including infection, autoimmune, and genetic disorders, as well as indeterminate hepatitis, which has a higher requirement for liver transplantation. Activation of the innate and adaptive immune systems leads to hepatocyte-specific injury which is mitigated by T regulatory cell activation. Recovery of the native liver depends on activation of apoptotic and regenerative pathways, including the integrated stress response (ISR; e.g., PERK), p53, and HNF4α. Loss-of-function mutations in these pathways cause recurrent ALF in response to non-hepatotropic viruses. Deeper understanding of these mechanisms will lead to improved diagnosis, management, and outcomes for pediatric ALF.

Regulatory T cells (Tregs) and their therapeutic potential against autoimmune disorders - Advances and challenges

Autoimmune diseases are caused when immune cells act against self-protein. This biological self-non-self-discrimination phenomenon is controlled by a distinct group of lymphocytes known as regulatory T cells (Tregs), which are key inflammatory response regulators and play a pivotal role in immune tolerance and homeostasis. Treg-mediated robust immunosuppression provides self-tolerance and protection against autoimmune diseases. However, once this system fails to operate or poorly operate, it leads to an extreme situation where immune system reacts against self-antigens and destroys host organs, thus causing autoimmune diseases. Tregs can target both innate and adaptive immunity via modulating multiple immune cells such as neutrophils, monocytes, antigen-presenting cells, B cells, and T cells. This review highlights the Treg-mediated immunosuppression, role of several markers and their interplay during Treg development and differentiation, and advances in therapeutic aspects of Treg cells to reduce severity of autoimmunity-related conditions along with emphasizing limitations and challenges of their usages.

Transcriptomic analysis of graft liver provides insight into the immune response of rat liver transplantation

Background

As an “immune-privileged organ”, the liver has higher rates of both spontaneous tolerance and operational tolerance after being transplanted compared with other solid organs. Also, a large number of patients still need to take long-term immunosuppression regimens. Liver transplantation (LT) rejection involves varieties of pathophysiological processes and cell types, and a deeper understanding of LT immune response is urgently needed.

Methods

Homogenic and allogeneic rat LT models were established, and recipient tissue was collected on postoperative day 7. The degree of LT rejection was evaluated by liver pathological changes and liver function. Differentially expressed genes (DEGs) were detected by transcriptome sequencing and confirmed by reverse transcription-polymerase chain reaction. The functional properties of DEGs were characterized by the Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Reactome pathway analyses. The cells infiltrating the graft and recipient spleen and peripheral blood were evaluated by immunofluorescence and flow cytometry.

Result

A total of 1,465 DEGs were screened, including 1,177 up-regulated genes and 288 down-regulated genes. GO enrichment and KEGG pathway analysis indicated that DEGs were involved in several immunobiological processes, including T cell activation, Th1, Th2 and Th17 cell differentiation, cytokine-cytokine receptor interaction and other immune processes. Reactome results showed that PD-1 signaling was enriched. Further research confirmed that mRNA expression of multiple immune cell markers increased and markers of T cell exhaustion significantly changed. Flow cytometry showed that the proportion of Treg decreased, and that of PD-1+CD4+ T cells and PD-1+CD8+ T cells increased in the allogeneic group.

Conclusion

Using an omic approach, we revealed that the development of LT rejection involved multiple immune cells, activation of various immune pathways, and specific alterations of immune checkpoints, which would benefit risk assessment in the clinic and understanding of pathogenesis regarding LT tolerance. Further clinical validations are warranted for our findings.

Targeting FGL2 in glioma immunosuppression and malignant progression

Glioblastoma (GBM) is the most malignant type of glioma with the worst prognosis. Traditional therapies (surgery combined with radiotherapy and chemotherapy) have limited therapeutic effects. As a novel therapy emerging in recent years, immunotherapy is increasingly used in glioblastoma (GBM), so we expect to discover more effective immune targets. FGL2, a member of the thrombospondin family, plays an essential role in regulating the activity of immune cells and tumor cells in GBM. Elucidating the role of FGL2 in GBM can help improve immunotherapy efficacy and design treatment protocols. This review discusses the immunosuppressive role of FGL2 in the GBM tumor microenvironment and its ability to promote malignant tumor progression while considering FGL2-targeted therapeutic strategies. Also, we summarize the molecular mechanisms of FGL2 expression on various immune cell types and discuss the possibility of FGL2 and its related mechanisms as new GBM immunotherapy.

Cell-in-Cell: From Cell Biology to Translational Medicine

Cell-in-cell structures (CICs) refer to cytoplasmic internalization of a cell by another cell, which are found throughout various biological systems and have been a part of scientific dogma for a long time. However, neither the mechanisms underlying this phenomenon nor their possible roles in disease development have resulted in major breakthroughs until recent years. In view of the ubiquity of CICs in inflammatory tissue and tumors, it is tempting to think that these specific structures could be associated with clinical diagnosis and treatment and thus would become a new hotspot for translational medicine. Translational medicine is a new concept in the field of international biomedical research that appeared in the last 20 years, which transforms basic research into clinical application. With the growing interest in this field, this review addresses recent research on CICs and their potential clinical implications in cytomorphological diagnosis and the pathology of human diseases, while discussing as yet unanswered questions. We also put forward future directions to reduce the gap in our knowledge caused by our currently limited understanding of CICs.

Notoginsenoside R1, An Active Compound from Panax notoginseng, Inhibits Hepatic Stellate Cell Activation and Liver Fibrosis via MAPK Signaling Pathway

Activation of the hepatic stellate cell is implicated in pathological vascularization during development of liver fibrosis. MAPK signaling is involved in the activation of hepatic stellate cell. Oxidative stress and inflammation are also involved in the pathogenesis of liver fibrosis. Notoginsenoside R1 is an effective saponin isolated from the roots of Panax notoginseng (Burk) F. H. Chen and exerts anti-oxidant, anti-inflammatory and anti-fibrotic roles in various diseases. However, the role of Notoginsenoside R1 in liver fibrosis has not been investigated yet. First, a rat model with liver fibrosis was established through oral gavage administration with carbon tetrachloride. Data from hematoxylin and eosin (H&E) and Masson's trichrome stainings showed that carbon tetrachloride induced severe hepatic damages, including inflammatory cell infiltration, lipid droplets deposition in hepatocytes and liver centrilobular necrosis. Meanwhile, the rats were also intraperitoneal injected with different concentrations of Notoginsenoside R1. Results demonstrated that Notoginsenoside R1 treatment suppressed the pathological changes in the livers with enhanced levels of ALB and TP, and reduced levels of ALP, AST and ALT. Second, Notoginsenoside R1 also significantly attenuated carbon tetrachloride-induced decrease in PPAR-[Formula: see text] and increase in Coll-a1, [Formula: see text]-SMA and TIMP1 in liver tissues ([Formula: see text][Formula: see text] 0.001). Third, the decrease in GSH, SOD and GST and increase in MDA, IL-1[Formula: see text], IL-6 and TNF-[Formula: see text] induced by carbon tetrachloride were markedly restored by Notoginsenoside R1 ([Formula: see text][Formula: see text] 0.001). Lastly, Notoginsenoside R1 counteracted with the promotive effects of carbon tetrachloride on levels of proteins involved in MAPK signaling, including phosphorylated p65 (p-p65), p-ERK, p-JNK and p-p38. In conclusion, Notoginsenoside R1 suppressed the activation of hepatic stellate cells and exerted anti- oxidant and anti-inflammatory to attenuate carbon tetrachloride-induced liver fibrosis through inactivation of NF-[Formula: see text]B and MAPK signaling.

Classification of Cell-in-Cell Structures: Different Phenomena with Similar Appearance

A phenomenon known for over 100 years named “cell-in-cell” (CIC) is now undergoing its renaissance, mostly due to modern cell visualization techniques. It is no longer an esoteric process studied by a few cell biologists, as there is increasing evidence that CICs may have prognostic and diagnostic value for cancer patients. There are many unresolved questions stemming from the difficulties in studying CICs and the limitations of current molecular techniques. CIC formation involves a dynamic interaction between an outer or engulfing cell and an inner or engulfed cell, which can be of the same (homotypic) or different kind (heterotypic). Either one of those cells appears to be able to initiate this process, which involves signaling through cell–cell adhesion, followed by cytoskeleton activation, leading to the deformation of the cellular membrane and movements of both cells that subsequently result in CICs. This review focuses on the distinction of five known forms of CIC (cell cannibalism, phagoptosis, enclysis, entosis, and emperipolesis), their unique features, characteristics, and underlying molecular mechanisms.