Regulation of tumour necrosis factor signalling: live or let die. Nat Rev Immunol. 2015;15:362-374. [PMID: 26008591 DOI: 10.1038/nri3834]

Network pharmacology-based predictions of active components and pharmacological mechanisms of Artemisia annua L. for the treatment of the novel Corona virus disease 2019 (COVID-19)

BACKGROUND

Novel Corona Virus Disease 2019 (COVID-19) is closely associated with cytokines storms. The Chinese medicinal herb Artemisia annua L. (A. annua) has been traditionally used to control many inflammatory diseases, such as malaria and rheumatoid arthritis. We performed network analysis and employed molecular docking and network analysis to elucidate active components or targets and the underlying mechanisms of A. annua for the treatment of COVID-19.

METHODS

Active components of A. annua were identified through the TCMSP database according to their oral bioavailability (OB) and drug-likeness (DL). Moreover, target genes associated with COVID-19 were mined from GeneCards, OMIM, and TTD. A compound-target (C-T) network was constructed to predict the relationship of active components with the targets. A Compound-disease-target (C-D-T) network has been built to reveal the direct therapeutic target for COVID-19. Molecular docking, molecular dynamics simulation studies (MD), and MM-GBSA binding free energy calculations were used to the closest molecules and targets between A. annua and COVID-19.

RESULTS

In our network, GO, and KEGG analysis indicated that A. annua acted in response to COVID-19 by regulating inflammatory response, proliferation, differentiation, and apoptosis. The molecular docking results manifested excellent results to verify the binding capacity between the hub components and hub targets in COVID-19. MD and MM-GBSA data showed quercetin to be the more effective candidate against the virus by target MAPK1, and kaempferol to be the other more effective candidate against the virus by target TP53. We identified A. annua's potentially active compounds and targets associated with them that act against COVID-19.

CONCLUSIONS

These findings suggest that A. annua may prevent and inhibit the inflammatory processes related to COVID-19.

Suppression of RIP1 activity via S415 dephosphorylation ameliorates obesity-related hepatic insulin resistance

OBJECTIVE

Receptor-interacting serine/threonine-protein kinase 1 (RIP1) is a well-documented key regulator of TNFα-mediated inflammation, apoptosis, and necroptosis, which contribute to the development of obesity-related metabolic diseases such as nonalcoholic steatohepatitis. However, the mechanism regarding how RIP1 influences obesity-related insulin resistance remains elusive.

METHODS

Primary hepatocytes with necrostatin 1 treatment or RIP1 expression were exposed to palmitic acid (PA), prior to the examination of cellular insulin signaling. Phosphorylation sites of RIP1 were detected by liquid chromatography with tandem mass spectrometry, and RIP1 variants with mutated phosphorylation sites were overexpressed in hepatocytes to identify the specific residue that influenced the RIP1-mediated insulin resistance. Adenovirus expressing RIP1 (S415A) mutant were administered into diet-induced obese mice to assess the effects on insulin sensitivity.

RESULTS

This study uncovered an aberrant increase in RIP1 activity during the development of obesity-induced insulin resistance. Inhibition of RIP1 activity with necrostatin 1 ameliorated PA- or high-fat diet-caused hepatic insulin resistance. With liquid chromatography with tandem mass spectrometry analysis and mutagenesis screening, S415, a novel phosphorylation site of RIP1, was identified to be responsible for RIP1-mediated insulin resistance. Loss-of-function mutation of S415 efficiently blunted RIP1-evoked insulin resistance in PA-treated hepatocytes or diet-induced obese mice.

CONCLUSIONS

These findings highlight the diabetogenic role of RIP1 S415 and propose RIP1 as a promising therapeutic target for type 2 diabetes.

Dichotomous Role of Tumor Necrosis Factor in Pulmonary Barrier Function and Alveolar Fluid Clearance

Alveolar-capillary leak is a hallmark of the acute respiratory distress syndrome (ARDS), a potentially lethal complication of severe sepsis, trauma and pneumonia, including COVID-19. Apart from barrier dysfunction, ARDS is characterized by hyper-inflammation and impaired alveolar fluid clearance (AFC), which foster the development of pulmonary permeability edema and hamper gas exchange. Tumor Necrosis Factor (TNF) is an evolutionarily conserved pleiotropic cytokine, involved in host immune defense against pathogens and cancer. TNF exists in both membrane-bound and soluble form and its mainly -but not exclusively- pro-inflammatory and cytolytic actions are mediated by partially overlapping TNFR1 and TNFR2 binding sites situated at the interface between neighboring subunits in the homo-trimer. Whereas TNFR1 signaling can mediate hyper-inflammation and impaired barrier function and AFC in the lungs, ligand stimulation of TNFR2 can protect from ventilation-induced lung injury. Spatially distinct from the TNFR binding sites, TNF harbors within its structure a lectin-like domain that rather protects lung function in ARDS. The lectin-like domain of TNF -mimicked by the 17 residue TIP peptide- represents a physiological mediator of alveolar-capillary barrier protection. and increases AFC in both hydrostatic and permeability pulmonary edema animal models. The TIP peptide directly activates the epithelial sodium channel (ENaC) -a key mediator of fluid and blood pressure control- upon binding to its α subunit, which is also a part of the non-selective cation channel (NSC). Activity of the lectin-like domain of TNF is preserved in complexes between TNF and its soluble TNFRs and can be physiologically relevant in pneumonia. Antibody- and soluble TNFR-based therapeutic strategies show considerable success in diseases such as rheumatoid arthritis, psoriasis and inflammatory bowel disease, but their chronic use can increase susceptibility to infection. Since the lectin-like domain of TNF does not interfere with TNF's anti-bacterial actions, while exerting protective actions in the alveolar-capillary compartments, it is currently evaluated in clinical trials in ARDS and COVID-19. A more comprehensive knowledge of the precise role of the TNFR binding sites versus the lectin-like domain of TNF in lung injury, tissue hypoxia, repair and remodeling may foster the development of novel therapeutics for ARDS.

TNF in the liver: targeting a central player in inflammation

Tumour necrosis factor-α (TNF) is a multifunctional cytokine. First recognized as an endogenous soluble factor that induces necrosis of solid tumours, TNF became increasingly important as pro-inflammatory cytokine being involved in the immunopathogenesis of several autoimmune diseases. In the liver, TNF induces numerous biological responses such as hepatocyte apoptosis and necroptosis, liver inflammation and regeneration, and autoimmunity, but also progression to hepatocellular carcinoma. Considering these multiple functions of TNF in the liver, we propose anti-TNF therapies that specifically target TNF signalling at the level of its specific receptors.

The Immune Underpinnings of Barrett's-Associated Adenocarcinogenesis: a Retrial of Nefarious Immunologic Co-Conspirators

There is no doubt that chronic gastroesophageal reflux disease increases the risk of esophageal adenocarcinoma (EAC) by several fold (odds ratio, 6.4; 95% CI, 4.6-9.1), and some relationships between reflux disease-mediated inflammation and oncogenic processes have been explored; however, the precise interconnections between the immune response and genomic instabilities underlying these pathologic processes only now are emerging. Furthermore, the precise cell of origin of the precancerous stages associated with EAC development, Barrett's esophagus, be it cardia resident or embryonic remnant, may shape our interpretation of the likely immune drivers. This review integrates the current collective knowledge of the immunology underlying EAC development and outlines a framework connecting proinflammatory pathways, such as those mediated by interleukin 1β, tumor necrosis factor α, leukemia inhibitory factor, interleukin 6, signal transduction and activator of transcription 3, nuclear factor-κB, cyclooxygenase-2, and transforming growth factor β, with oncogenic pathways in the gastroesophageal reflux disease-Barrett's esophagus-EAC cancer sequence. Further defining these immune and molecular railroads may show a map of the routes taken by gastroesophageal cells on their journey toward EAC tumor phylogeny. The selective pressures applied by this immune-induced journey likely impact the phenotype and genotype of the resulting oncogenic destination and further exploration of lesser-defined immune drivers may be useful in future individualized therapies or enhanced selective application of recent immune-driven therapeutics.

Aging-elevated inflammation promotes DNMT3A R878H-driven clonal hematopoiesis

Aging-elevated DNMT3A R882H-driven clonal hematopoiesis (CH) is a risk factor for myeloid malignancies remission and overall survival. Although some studies were conducted to investigate this phenomenon, the exact mechanism is still under debate. In this study, we observed that DNMT3A R878H bone marrow cells (human allele: DNMT3A R882H) displayed enhanced reconstitution capacity in aged bone marrow milieu and upon inflammatory insult. DNMT3A R878H protects hematopoietic stem and progenitor cells from the damage induced by chronic inflammation, especially TNFα insults. Mechanistically, we identified that RIPK1–RIPK3–MLKL-mediated necroptosis signaling was compromised in R878H cells in response to proliferation stress and TNFα insults. Briefly, we elucidated the molecular mechanism driving DNMT3A R878H-based clonal hematopoiesis, which raises clinical value for treating DNMT3A R882H-driven clonal hematopoiesis and myeloid malignancies with aging.

TNF-TNFR1 Signaling Enhances the Protection Against Neospora caninum Infection

Neospora caninum is a protozoan associated with abortions in ruminants and neuromuscular disease in dogs. Classically, the immune response against apicomplexan parasites is characterized by the production of proinflammatory cytokines, such as IL-12, IFN-γ and TNF. TNF is mainly produced during the acute phases of the infections and binds to TNF receptor 1 (CD120a, p55, TNFR1) activating a variety of cells, hence playing an important role in the induction of the inflammatory process against diverse pathogens. Thus, in this study, we aimed to evaluate the role of TNF in cellular and humoral immune responses during N. caninum infection. For this purpose, we used a mouse model of infection based on wildtype (WT) and genetically deficient C57BL/6 mice in TNFR1 (Tnfr1 ^-/-). We observed that Tnfr1 ^-/- mice presented higher mortality associated with inflammatory lesions and increased parasite burden in the brain after the infection with N. caninum tachyzoites. Moreover, Tnfr1 ^-/- mice showed a reduction in nitric oxide (NO) levels in vivo. We also observed that Tnfr1 ^-/- mice showed enhanced serum concentration of antigen-specific IgG2 subclass, while IgG1 production was significantly reduced compared to WT mice, suggesting that TNFR1 is required for regular IgG subclass production and antigen recognition. Based on our results, we conclude that the TNF-TNFR1 complex is crucial for mediating host resistance during the infection by N. caninum.

Role of the Interaction of Tumor Necrosis Factor-α and Tumor Necrosis Factor Receptors 1 and 2 in Bone-Related Cells

Tumor necrosis factor-α (TNF-α) is a pleiotropic cytokine expressed by macrophages, monocytes, and T cells, and its expression is triggered by the immune system in response to pathogens and their products, such as endotoxins. TNF-α plays an important role in host defense by inducing inflammatory reactions such as phagocytes and cytocidal systems activation. TNF-α also plays an important role in bone metabolism and is associated with inflammatory bone diseases. TNF-α binds to two cell surface receptors, the 55kDa TNF receptor-1 (TNFR1) and the 75kDa TNF receptor-2 (TNFR2). Bone is in a constant state of turnover; it is continuously degraded and built via the process of bone remodeling, which results from the regulated balance between bone-resorbing osteoclasts, bone-forming osteoblasts, and the mechanosensory cell type osteocytes. Precise interactions between these cells maintain skeletal homeostasis. Studies have shown that TNF-α affects bone-related cells via TNFRs. Signaling through either receptor results in different outcomes in different cell types as well as in the same cell type. This review summarizes and discusses current research on the TNF-α and TNFR interaction and its role in bone-related cells.

Ultrasonic Elastography of the Rectus Femoris, a Potential Tool to Predict Sarcopenia in Patients With Chronic Obstructive Pulmonary Disease

Purpose: Skeletal muscle dysfunction is common in patients with chronic obstructive pulmonary disease (COPD) and is associated with a poor prognosis. Abnormal muscle quantity of the lower limbs is a manifestation of skeletal muscle dysfunction in patients with COPD. Shear wave ultrasound elastography (SWE) is a novel and possible tool to evaluate qualitative muscle parameters. This study explores the feasibility of SWE to measure the stiffness of the rectus femoris and evaluates its value in predicting sarcopenia in patients with COPD.

Methods: Ultrasound examination of the rectus femoris was performed to determine the mean elasticity index (SWE_mean), cross-sectional area (RF_csa), and thickness (RF_thick) using grayscale ultrasonography (US) and SWE in 53 patients with COPD and 23 age-matched non-COPD healthy controls. The serum levels of circulating biomarkers (GDF15, resistin, and TNF-α) were measured using ELISA. The definition of sarcopenia followed the guidelines from the Asian Working Group for Sarcopenia. Receiver operating characteristic (ROC) curve analysis of the SWE_mean, RF_thick, and RF_csa was used to evaluate their predictive ability for sarcopenia.

Results: The intraobserver and interobserver repeatability of SWE performance was excellent (all correlation coefficients > 0.95; p < 0.05). The SWE_mean of the rectus femoris in patients with COPD (8.98 ± 3.12 kPa) was decreased compared with that in healthy controls (17.00 ± 5.14 kPa) and decreased with advanced global initiative for chronic obstructive lung disease (GOLD) stage. Furthermore, SWE_mean was found to be independent of sex, height, and body mass, and a lower SWE_mean in patients with COPD was positively associated with reduced pulmonary function, worse physical function, poor exercise tolerance, decreased muscle strength, and worse dyspnea index score. The correlation between physical function [five-repetition sit-to-stand test (5STST)], muscle function, and SWE_mean was higher than those of RF_thick and RF_csa. In addition, SWE_mean was negatively correlated with serum GDF15 levels (r = −0.472, p < 0.001), serum resistin levels (r = −0.291, p = 0.035), and serum TNF-α levels (r = −0.433, p = 0.001). Finally, the predictive power of SWE_mean [area under the curve (AUC): 0.863] in the diagnosis of sarcopenia was higher than that of RF_thick (AUC: 0.802) and RF_csa (AUC: 0.816).

Conclusion: Compared with grayscale US, SWE was not affected by the patient’s height, weight, or BMI and better represented skeletal muscle function and physical function. Furthermore, SWE is a promising potential tool to predict sarcopenia in patients with COPD.

The Impact of Hyaluronan on Tumor Progression in Cutaneous Melanoma

The incidence of cutaneous melanoma is rapidly increasing worldwide. Cutaneous melanoma is an aggressive type of skin cancer, which originates from malignant transformation of pigment producing melanocytes. The main risk factor for melanoma is ultraviolet (UV) radiation, and thus it often arises from highly sun-exposed skin areas and is characterized by a high mutational burden. In addition to melanoma-associated mutations such as BRAF, NRAS, PTEN and cell cycle regulators, the expansion of melanoma is affected by the extracellular matrix surrounding the tumor together with immune cells. In the early phases of the disease, hyaluronan is the major matrix component in cutaneous melanoma microenvironment. It is a high-molecular weight polysaccharide involved in several physiological and pathological processes. Hyaluronan is involved in the inflammatory reactions associated with UV radiation but its role in melanomagenesis is still unclear. Although abundant hyaluronan surrounds epidermal and dermal cells in normal skin and benign nevi, its content is further elevated in dysplastic lesions and local tumors. At this stage hyaluronan matrix may act as a protective barrier against melanoma progression, or alternatively against immune cell attack. While in advanced melanoma, the content of hyaluronan decreases due to altered synthesis and degradation, and this correlates with poor prognosis. This review focuses on hyaluronan matrix in cutaneous melanoma and how the changes in hyaluronan metabolism affect the progression of melanoma.

A De Novo Optimized Cell-Free System for the Expression of Soluble and Active Human Tumor Necrosis Factor-Alpha

Simple Summary

As a result of increasing demand for the pleiotropic cytokine TNF-α, recombinant human TNF-α protein with appropriate bioactivities was produced in several heterologous in vivo expression systems. While in vivo expression of this cytokine is laborious and lengthy, cell-free or in vitro expression system has the benefits of speed, simplicity, flexibility, focus of all the system energy on target protein synthesis alone, besides high soluble and functional protein yield. Therefore, we employed and optimized an E. coli-based cell-free system for the first time to express recombinant human TNF-α. Our findings revealed that cell-free expression system can be an alternative platform for producing soluble and functionally active recombinant TNF-α with a yield of 390 µg/mL in only 2 h at a temperature of 40 °C for further research and clinical trials.

Abstract

Cell-free (in vitro) expression is a robust alternative platform to the cell-based (in vivo) system for recombinant protein production. Tumor necrosis factor-alpha (TNF-α) is an effective pro-inflammatory cytokine with pleiotropic effects. The aim of the current study was de novo optimized expression of soluble and active human TNF-α by an in vitro method in an E. coli-based cell-free protein synthesis (CFPS) system and its biological activity evaluation. The codon-optimized synthetic human TNF-α gene was constructed by a two-step PCR, cloned into pET101/D-TOPO vector and then expressed by the E. coli CFPS system. Cell-free expression of the soluble protein was optimized using a response surface methodology (RSM). The anticancer activity of purified human TNF-α was assessed against three human cancer cell lines: Caco-2, HepG-2 and MCF-7. Data from RSM revealed that the lowest value (7.2 µg/mL) of cell-free production of recombinant human TNF-α (rhTNF-α) was obtained at a certain incubation time (6 h) and incubation temperature (20 °C), while the highest value (350 µg/mL) was recorded at 4 h and 35 °C. This rhTNF-α showed a significant anticancer potency. Our findings suggest a cell-free expression system as an alternative platform for producing soluble and functionally active recombinant TNF-α for further research and clinical trials.

The Compound (E)-2-Cyano-N,3-diphenylacrylamide (JMPR-01): A Potential Drug for Treatment of Inflammatory Diseases

The compound (E)-2-cyano-N,3-diphenylacrylamide (JMPR-01) was structurally developed using bioisosteric modifications of a hybrid prototype as formed from fragments of indomethacin and paracetamol. Initially, in vitro assays were performed to determine cell viability (in macrophage cultures), and its ability to modulate the synthesis of nitrite and cytokines (IL-1β and TNFα) in non-cytotoxic concentrations. In vivo, anti-inflammatory activity was explored using the CFA-induced paw edema and zymosan-induced peritonitis models. To investigate possible molecular targets, molecular docking was performed with the following crystallographic structures: LT-A4-H, PDE4B, COX-2, 5-LOX, and iNOS. As results, we observed a significant reduction in the production of nitrite and IL-1β at all concentrations used, and also for TNFα with JMPR-01 at 50 and 25 μM. The anti-edematogenic activity of JMPR-01 (100 mg/kg) was significant, reducing edema at 2-6 h, similar to the dexamethasone control. In induced peritonitis, JMPR-01 reduced leukocyte migration by 61.8, 68.5, and 90.5% at respective doses of 5, 10, and 50 mg/kg. In silico, JMPR-01 presented satisfactory coupling; mainly with LT-A4-H, PDE4B, and iNOS. These preliminary results demonstrate the strong potential of JMPR-01 to become a drug for the treatment of inflammatory diseases.

Inhibition of ADAM17 impairs endothelial cell necroptosis and blocks metastasis

Metastasis is the major cause of death in cancer patients. Circulating tumor cells need to migrate through the endothelial layer of blood vessels to escape the hostile circulation and establish metastases at distant organ sites. Here, we identified the membrane-bound metalloprotease ADAM17 on endothelial cells as a key driver of metastasis. We show that TNFR1-dependent tumor cell-induced endothelial cell death, tumor cell extravasation, and subsequent metastatic seeding is dependent on the activity of endothelial ADAM17. Moreover, we reveal that ADAM17-mediated TNFR1 ectodomain shedding and subsequent processing by the γ-secretase complex is required for the induction of TNF-induced necroptosis. Consequently, genetic ablation of ADAM17 in endothelial cells as well as short-term pharmacological inhibition of ADAM17 prevents long-term metastases formation in the lung. Thus, our data identified ADAM17 as a novel essential regulator of necroptosis and as a new promising target for antimetastatic and advanced-stage cancer therapies.

Cancer Stem Cells: An Ever-Hiding Foe

Cancer stem cells are a population of cells enable to reproduce the original phenotype of the tumor and capable to self-renewal, which is crucial for tumor proliferation, differentiation, recurrence, and metastasis, as well as chemoresistance. Therefore, the cancer stem cells (CSCs) have become one of the main targets for anticancer therapy and many ongoing clinical trials test anti-CSCs efficacy of plenty of drugs. This chapter describes CSCs starting from general description of this cell population, through CSCs markers, signaling pathways, genetic and epigenetic regulation, role of epithelial-mesenchymal transition (EMT) transition and autophagy, cooperation with microenvironment (CSCs niche), and finally role of CSCs in escaping host immunosurveillance against cancer.

TNFα Induces LGR5+ Stem Cell Dysfunction In Patients With Crohn's Disease

BACKGROUND & AIMS

Tumor necrosis factor alpha (TNFα) is considered a major tissue damage-promoting effector in Crohn's disease (CD) pathogenesis. Patient-derived intestinal organoid (enteroid) recapitulates the disease-specific characteristics of the intestinal epithelium. This study aimed to evaluate the intestinal epithelial responses to TNFα in enteroids derived from healthy controls and compare them with those of CD patient-derived enteroids.

METHODS

Human enteroids derived from patients with CD and controls were treated with TNFα (30 ng/mL), and cell viability and gene expression patterns were evaluated.

RESULTS

TNFα induced MLKL-mediated necroptotic cell death, which was more pronounced in CD patient-derived enteroids than in control enteroids. Immunohistochemistry and RNA sequencing revealed that treatment with TNFα caused expansion of the intestinal stem cell (ISC) populations. However, expanded ISC subpopulations differed in control and CD patient-derived enteroids, with LGR5+ active ISCs in control enteroids and reserve ISCs, such as BMI1+ cells, in CD patient-derived enteroids. In single-cell RNA sequencing, LGR5+ ISC-enriched cell cluster showed strong expression of TNFRSF1B (TNFR2) and cyclooxygenase-prostaglandin E2 (PGE2) activation. In TNFα-treated CD patient-derived enteroids, exogenous PGE2 (10 nmol/L) induced the expansion of the LGR5+ ISC population and improved organoid-forming efficiency, viability, and wound healing.

CONCLUSIONS

TNFα increases necroptosis of differentiated cells and induces the expansion of LGR5+ ISCs. In CD patient-derived enteroids, TNFα causes LGR5+ stem cell dysfunction (expansion failure), and exogenous PGE2 treatment restored the functions of LGR5+ stem cells. Therefore, PGE2 can be used to promote mucosal healing in patients with CD.

Systemic Interleukins' Profile in Early and Advanced Colorectal Cancer

Tumor microenvironment (TME) is characterized by mutual interactions of the tumor, stromal and immune cells. Early and advanced colorectal tumors differ in structure and present altered serum cytokine levels. Mutual crosstalk among TME infiltrating cells may shift the balance into immune suppressive or pro-inflammatory, antitumor response this way influencing patients' prognosis. Cancer-related inflammation affects all the body and this way, the systemic level of cytokines could reflect TME processes. Despite numerous studies, it is still not known how systemic cytokines levels change during colorectal cancer (CRC) tumor development. Better understanding tumor microenvironment processes could help in planning therapeutic interventions and more accurate patient prognosis. To contribute to the comprehension of these processes within TME, we reviewed cytokines levels from clinical trials in early and advanced colorectal cancer. Presented data were analyzed in the context of experimental studies and studies analyzing tumor infiltration with immune cells. The review summarizes clinical data of cytokines secreted by tumor microenvironment cells: lymphocytes T helper 1 (Th1), lymphocytes T helper 2 (Th2), lymphocytes T helper 17 (Th17), regulatory T cells (Treg cells), regulatory T cells (Breg cells), M1/M2 macrophages, N1/N2 neutrophils, myeloid-derived suppressor cells (MDSC), dendritic cells (DC), innate lymphoid cells (ILC) natural killer (NK) cells and tumor cells.

From Apoptosis to Necroptosis: The Death Wishes to Cancer

DNA mutation is a common event in the human body, but in most situations, it is fixed right away by the DNA damage response program. In case the damage is too severe to repair, the programmed cell death system will be activated to get rid of the cell. However, if the damage affects some critical components of this system, the genetic scars are kept and multiply through mitosis, possibly leading to cancer someday. There are many forms of programmed cell death, but apoptosis and necroptosis represent the default and backup strategy, respectively, in the maintenance of optimal cell population as well as in cancer prevention. For the same reason, the ideal approach for cancer treatment is to induce apoptosis in the cancer cells because it proceeds 20 times faster than tumor cell proliferation and leaves no mess behind. Induction of necroptosis can be the second choice in case apoptosis becomes hard to achieve, however, necroptosis finishes the job at a cost-inflammation.

Isolation, physicochemical, and structure-function relationship of the hydrophobic variant of Fc-fusion proteins that bind to TNF-α receptor, HS002 and HS002A

HS002 is the recombinant human tumor necrosis factor-α receptor Ⅱ: IgG Fc fusion protein licensed in China to treat rheumatism and psoriasis. The aim of this study was to isolate and characterize the hydrophobic freeze-dried powder injection (HS002) and ampoule injection (HS002A) variants derived from proteins of the same sequence and then to explore the structure-function relationship. Extensive physicochemical and structural testing was performed during a side-by-side comparison of the monomer peak and variant. Then the TNF-α-related binding activity, cell biological activity and affinity with FcRn were analyzed. Finally, a transformation study of the hydrophobic variant was performed under serum-like redox conditions. This research revealed that HS002A has similar physicochemical and structure-function relationship profiles to those of HS002. The hydrophobic variant exhibited the presence of new incorrect disulfide bridging. At the same time, this novel disulfide scrambled species structure-function relationship was found to be the molecular basis for reduced TNF-α binding and cell biological activities. In addition, incorrect disulfide bridging was found to be reversible under serum-like redox conditions, restoring TNF-α binding and cell biological activities to almost normal levels, all of which indicate that the variant is probably irrelevant to clinical efficacy once the drug enters the bloodstream.

Bcl-3 promotes TNF-induced hepatocyte apoptosis by regulating the deubiquitination of RIP1

Tumor necrosis factor-α (TNF) is described as a main regulator of cell survival and apoptosis in multiple types of cells, including hepatocytes. Dysregulation in TNF-induced apoptosis is associated with many autoimmune diseases and various liver diseases. Here, we demonstrated a crucial role of Bcl-3, an IκB family member, in regulating TNF-induced hepatic cell death. Specifically, we found that the presence of Bcl-3 promoted TNF-induced cell death in the liver, while Bcl-3 deficiency protected mice against TNF/D-GalN induced hepatoxicity and lethality. Consistently, Bcl-3-depleted hepatic cells exhibited decreased sensitivity to TNF-induced apoptosis when stimulated with TNF/CHX. Mechanistically, the in vitro results showed that Bcl-3 interacted with the deubiquitinase CYLD to synergistically switch the ubiquitination status of RIP1 and facilitate the formation of death-inducing Complex II. This complex further resulted in activation of the caspase cascade to induce apoptosis. By revealing this novel role of Bcl-3 in regulating TNF-induced hepatic cell death, this study provides a potential therapeutic target for liver diseases caused by TNF-related apoptosis.

Interleukin-10-Mediated Lymphopenia Caused by Acute Infection with Foot-and-Mouth Disease Virus in Mice

Foot-and-mouth disease (FMD) is characterized by a pronounced lymphopenia that is associated with immune suppression. However, the mechanisms leading to lymphopenia remain unclear. In this study, the number of total CD4⁺, CD8⁺ T cells, B cells, and NK cells in the peripheral blood were dramatically reduced in C57BL/6 mice infected with foot-and-mouth disease virus (FMDV) serotype O, and it was noted that mice with severe clinical symptoms had expressively lower lymphocyte counts than mice with mild or without clinical symptoms, indicating that lymphopenia was associated with disease severity. A further analysis revealed that lymphocyte apoptosis and trafficking occurred after FMDV infection. In addition, coinhibitory molecules were upregulated in the expression of CD4⁺ and CD8⁺ T cells from FMDV-infected mice, including CTLA-4, LAG-3, 2B4, and TIGIT. Interestingly, the elevated IL-10 in the serum was correlated with the appearance of lymphopenia during FMDV infection but not IL-6, IL-2, IL-17, IL-18, IL-1β, TNF-α, IFN-α/β, TGF-β, and CXCL1. Knocking out IL-10 (IL-10^-/-) mice or blocking IL-10/IL-10R signaling in vivo was able to prevent lymphopenia via downregulating apoptosis, trafficking, and the coinhibitory expression of lymphocytes in the peripheral blood, which contribute to enhance the survival of mice infected with FMDV. Our findings support that blocking IL-10/IL-10R signaling may represent a novel therapeutic approach for FMD.

Unexpected similarity between HIV-1 reverse transcriptase and tumor necrosis factor binding sites revealed by computer vision

Rationalizing the identification of hidden similarities across the repertoire of druggable protein cavities remains a major hurdle to a true proteome-wide structure-based discovery of novel drug candidates. We recently described a new computational approach (ProCare), inspired by numerical image processing, to identify local similarities in fragment-based subpockets. During the validation of the method, we unexpectedly identified a possible similarity in the binding pockets of two unrelated targets, human tumor necrosis factor alpha (TNF-α) and HIV-1 reverse transcriptase (HIV-1 RT). Microscale thermophoresis experiments confirmed the ProCare prediction as two of the three tested and FDA-approved HIV-1 RT inhibitors indeed bind to soluble human TNF-α trimer. Interestingly, the herein disclosed similarity could be revealed neither by state-of-the-art binding sites comparison methods nor by ligand-based pairwise similarity searches, suggesting that the point cloud registration approach implemented in ProCare, is uniquely suited to identify local and unobvious similarities among totally unrelated targets.

TNF-α in Uveitis: From Bench to Clinic

Uveitis is an inflammation of the iris, ciliary body, vitreous, retina, or choroid, which has been shown to be the first manifestation of numerous systemic diseases. Studies about the immunopathogenesis and treatment of uveitis are helpful to comprehend systemic autoimmune diseases, and delay the progression of systemic autoimmune diseases, respectively. Tumor necrosis factor-alpha (TNF-α), a pleiotropic cytokine, plays a pivotal role in intraocular inflammation based on experimental and clinical data. Evidence of the feasibility of using anti-TNF-α agents for uveitis management has increased. Although there are numerous studies on TNF-α in various autoimmune diseases, the pathological mechanism and research progress of TNF-α in uveitis have not been reviewed. Therefore, the objective of this review is to provide a background on the role of TNF-α in the immunopathogenesis of uveitis, as well as from bench to clinical research progress, to better guide TNF-α-based therapeutics for uveitis.

Thrombin induces pro-inflammatory and anti-inflammatory cytokines secretion from human mast cell line (HMC-1) via protease-activated receptors

Thrombin-induced mast cell activation represents cross-talk between coagulation and inflammation. However, there is still controversy concerning the pro- or anti-inflammatory effects mast cells have in response to thrombin signaling. Human mast cell HMC-1 was incubated with 0.2 U/mL thrombin. Cells and supernatants were collected. Production of pro- and anti-inflammatory mediators was determined by quantitative PCR (qPCR) and enzyme-linked immunosorbent assay (ELISA). Expression of proteinase-activated receptor-1 (PAR1) and -4 (PAR4) mRNA in HMC-1 cells was analyzed by qPCR. Activation of mitogen-activated protein kinases (MAPKs) was measured by immunoblotting. Furthermore, the impact of PAR1 inhibitor (SCH79797) and agonist (TFLLR-NH₂), PAR4 inhibitor (BMS986120) and agonist (AYPGKF-NH₂), and MAPK inhibitors (SB203580, PD98059, and SP600125) on the production of mediators was evaluated using qPCR and ELISA. Thrombin exposure increased pro- and anti-inflammatory mediators, expression of PAR1 and PAR4 mRNA, and phosphorylation of JNK, p38, and ERK1/2 MAPKs in HMC-1 cells. SCH79797, BMS986120, and MAPK inhibitors (SB203580, PD98059, and SP600125) were inhibited, while TFLLR-NH₂ and AYPGKF-NH₂ promoted pro- and anti-inflammatory cytokines in this process. HMC-1 produces pro- and anti-inflammatory cytokines after thrombin incubation, namely PAR1 and PAR4. Alongside HMC-1, MAPK signaling pathways are involved in the production of these mediators. The mast cells showed dual activation after thrombin stimulation.

Dysregulated Inflammation During Obesity: Driving Disease Severity in Influenza Virus and SARS-CoV-2 Infections

Acute inflammation is a critical host defense response during viral infection. When dysregulated, inflammation drives immunopathology and tissue damage. Excessive, damaging inflammation is a hallmark of both pandemic influenza A virus (IAV) infections and Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) infections. Chronic, low-grade inflammation is also a feature of obesity. In recent years, obesity has been recognized as a growing pandemic with significant mortality and associated costs. Obesity is also an independent risk factor for increased disease severity and death during both IAV and SARS-CoV-2 infection. This review focuses on the effect of obesity on the inflammatory response in the context of viral respiratory infections and how this leads to increased viral pathology. Here, we will review the fundamentals of inflammation, how it is initiated in IAV and SARS-CoV-2 infection and its link to disease severity. We will examine how obesity drives chronic inflammation and trained immunity and how these impact the immune response to IAV and SARS-CoV-2. Finally, we review both medical and non-medical interventions for obesity, how they impact on the inflammatory response and how they could be used to prevent disease severity in obese patients. As projections of global obesity numbers show no sign of slowing down, future pandemic preparedness will require us to consider the metabolic health of the population. Furthermore, if weight-loss alone is insufficient to reduce the risk of increased respiratory virus-related mortality, closer attention must be paid to a patient’s history of health, and new therapeutic options identified.

Deciphering glial scar after spinal cord injury

Spinal cord injury (SCI) often leads to permanent disability, which is mainly caused by the loss of functional recovery. In this review, we aimed to investigate why the healing process is interrupted. One of the reasons for this interruption is the formation of a glial scar around the severely damaged tissue, which is usually covered by reactive glia, macrophages and fibroblasts. Aiming to clarify this issue, we summarize the latest research findings pertaining to scar formation, tissue repair, and the divergent roles of blood-derived monocytes/macrophages, ependymal cells, fibroblasts, microglia, oligodendrocyte progenitor cells (OPCs), neuron-glial antigen 2 (NG2) and astrocytes during the process of scar formation, and further analyse the contribution of these cells to scar formation. In addition, we recapitulate the development of therapeutic treatments targeting glial scar components. Altogether, we aim to present a comprehensive decoding of the glial scar and explore potential therapeutic strategies for improving functional recovery after SCI.

Unleashing TNF cytotoxicity to enhance cancer immunotherapy

Tumor necrosis factor (TNF) is a proinflammatory cytokine that is produced and secreted by cytotoxic lymphocytes upon tumor target recognition. Depending on the context, TNF can mediate either pro-survival or pro-death signals. The potential cytotoxicity of T cell-produced TNF, particularly in the context of T cell-directed immunotherapies, has been largely overlooked. However, a spate of recent studies investigating tumor immune evasion through the application of CRISPR-based gene-editing screens have highlighted TNF-mediated killing as an important component of the mammalian T cell antitumor repertoire. In the context of the current understanding of the role of TNF in antitumor immunity, we discuss these studies and touch on their therapeutic implications. Collectively, we provide an enticing prospect to augment immunotherapy responses through TNF cytotoxicity.

Effect of pyrroloquinoline quinone on lipopolysaccharide-induced autophagy in HAPI microglia cells

Background

Pyrroloquinoline quinone (PQQ) is involved in various physiological and biochemical processes, including antioxidant, cell proliferation, and mitochondrial formation. It plays a vital role in protecting neurons. However, the effect of PQQ on microglia, an inflammatory cell of the central nervous system (CNS), is still unclear. This study aimed to investigate the biological role and neuroprotective mechanism of PQQ in HAPI microglial cells exposed to lipopolysaccharide (LPS).

Methods

Western blot (WB) was used to detect apoptosis and autophagy-related molecules Bax, Bcl2, active-caspase-3, caspase-3, LC3, lysosomal associated membrane protein 2 (LAMP2), AKT, tumor necrosis factor receptor (TNFR) 1, and TNFR2 expression. The phosphatidylinositol 3-kinase (PI3K)/Akt inhibitor LY294002 was used to block the Akt pathway. WB detected the effects of PI3K on autophagy and TNFR1 and TNFR2 expression. The localization of active-caspase-3, caspase-3, LC3, LAMP2, TNFR1, and TNFR2 in cells was observed by immunofluorescence staining. The effect of PQQ on the cell cycle was examined by flow cytometry. We used 5-Ethynyl-2’-deoxyuridine (EdU) assay to detect cell proliferation. The migration ability of cells under different conditions was detected by scratch test and Transwell assay.

Results

Our results showed that there were different effects on the apoptosis-related molecules Bcl2/Bax and active-caspase-3/caspase in HAPI microglial cells treated with PQQ at different times. PQQ had no significant effect on the LC3b/a ratio in the early stage, which was upregulated in the later stage. The expression of LAMP2 was significantly increased in both early and late stages after PQQ treatment. At the same time, we found that PQQ can reverse the translocation of LAMP2 from the cytoplasm to the nucleus in LPS-induced HAPI microglia. After PQQ treatment, TNFR1 was significantly decreased, but TNFR2 increased in LPS-induced HAPI microglia. It may be that PQQ works through the PI3K/Akt signaling pathway to up-regulate LC3, LAMP2, and TNFR1 and down-regulate TNFR2 in LPS-induced HAPI microglia. However, PQQ has little effect on LPS-induced proliferation, cell cycle, and migration of HAPI microglia.

Conclusions

In LPS-induced HAPI microglia, PQQ reduces the apoptosis level and increases that of autophagy. In addition, PQQ changes the distribution of LAMP2 in the cytoplasm and nucleus, which is regulated through the PI3K/Akt signaling pathway.

Two Faces of Macrophages: Training and Tolerance

Macrophages are present in almost all body tissues. They detect and quickly respond to “environmental signals” in the tissue. Macrophages have been associated with numerous beneficial roles, such as host defense, wound healing, and tissue regeneration; however, they have also been linked to the development of diverse illnesses, particularly cancers and autoimmune disorders. Complex signaling, epigenetic, and metabolic pathways drive macrophage training and tolerance. The induced intracellular program differs depending on the type of initial stimuli and the tissue microenvironment. Due to the essential roles of macrophages in homeostatic and their association with the pathogenesis of inflammatory diseases, recent studies have investigated the molecular mechanisms of macrophage training and tolerance. This review discusses the role of factors involved in macrophage training and tolerance, along with the current studies in human diseases.

Selective Induction of Cell Death in Human M1 Macrophages by Smac Mimetics Is Mediated by cIAP-2 and RIPK-1/3 through the Activation of mTORC

Inflammatory macrophages have been implicated in many diseases, including rheumatoid arthritis and inflammatory bowel disease. Therefore, targeting macrophage function and activation may represent a potential strategy to treat macrophage-associated diseases. We have previously shown that IFN-γ-induced differentiation of human M0 macrophages toward proinflammatory M1 state rendered them highly susceptible to the cytocidal effects of second mitochondria-derived activator of caspases mimetics (SMs), antagonist of the inhibitors of apoptosis proteins (IAPs), whereas M0 and anti-inflammatory M2c macrophages were resistant. In this study, we investigated the mechanism governing SM-induced cell death during differentiation into M1 macrophages and in polarized M1 macrophages. IFN-γ stimulation conferred on M0 macrophages the sensitivity to SM-induced cell death through the Jak/STAT, IFN regulatory factor-1, and mammalian target of rapamycin complex-1 (mTORC-1)/ribosomal protein S6 kinase pathways. Interestingly, mTORC-1 regulated SM-induced cell death independent of M1 differentiation. In contrast, SM-induced cell death in polarized M1 macrophages is regulated by the mTORC-2 pathway. Moreover, SM-induced cell death is regulated by cellular IAP (cIAP)-2, receptor-interacting protein kinase (RIPK)-1, and RIPK-3 degradation through mTORC activation during differentiation into M1 macrophages and in polarized M1 macrophages. In contrast to cancer cell lines, SM-induced cell death in M1 macrophages is independent of endogenously produced TNF-α, as well as the NF-κB pathway. Collectively, selective induction of cell death in human M1 macrophages by SMs may be mediated by cIAP-2, RIPK-1, and RIPK-3 degradation through mTORC activation. Moreover, blocking cIAP-1/2, mTORC, or IFN regulatory factor-1 may represent a promising therapeutic strategy to control M1-associated diseases.

Naringin Exhibited Therapeutic Effects against DSS-Induced Mice Ulcerative Colitis in Intestinal Barrier-Dependent Manner

Naringin is a kind of multi-source food additive which has been explored broadly for its various biological activities and therapeutic potential. In the present study, the protective effect and mechanism of naringin on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice were investigated. The results showed that naringin significantly alleviated DSS-induced colitis symptoms, including disease activity index (DAI), colon length shortening, and colon pathological damage. The tissue and serum secretion of inflammatory cytokines, as well as the oxidative stress, were decreased accordingly upon naringin intervention. Naringin also decreased the proteins involved in inflammation and increased the expression of tight junction (TJ) proteins. Moreover, naringin increased the relative abundance of Firmicutes/Bacteroides and reduced the content of Proteobacteria to improve the intestinal flora disorder caused by DSS, which promotes the intestinal health of mice. It was concluded that naringin can significantly ameliorate the pathogenic symptoms of UC through inhibiting inflammatory response and regulating intestinal microbiota, which might be a promising natural therapeutic agent for the dietary treatment of UC and the improvement of intestinal symbiosis.

Generation and characterization of novel co-stimulatory anti-mouse TNFR2 antibodies

Tumor necrosis factor receptor 2 (TNFR2) has gained much research interest in recent years because of its potential pivotal role in autoimmune disease and cancer. However, its function in regulating different immune cells is not well understood. There is a need for well-characterized reagents to selectively modulate TNFR2 function, thereby enabling definition of TNFR2-dependent biology in human and mouse surrogate models. Here, we describe the generation, production, purification, and characterization of a panel of novel antibodies targeting mouse TNFR2. The antibodies display functional differences in binding affinity and potency to block TNFα. Furthermore, epitope binding showed that the anti-mTNFR2 antibodies target different domains on the TNFR2 protein, associated with varying capacity to enhance CD8⁺ T-cell activation and costimulation. Moreover, the anti-TNFR2 antibodies demonstrate binding to isolated splenic mouse Tregs ex vivo and activated CD8+ cells, reinforcing their potential use to establish TNFR2-dependent immune modulation in translational models of autoimmunity and cancer.

TNF antagonizes CCN1 in apoptosis in esophageal adenocarcinoma

TNF signaling mostly supports cell growth by activating NFκB and only induces cell death when NFκB activation fails. CCN1 is a matricellular protein that has been reported capable to convert TNF from a pro-survival factor into a stimulus for cell death without interfering with NFκB signaling. In this study, we examined the relationship between CCN1 and TNF in the context of esophageal adenocarcinoma and found that CCN1 did not help TNF to induce cell death when they were together, instead, it inhibited TNF expression, as well as TNF-induced JNK activation and apoptosis. CCN1 induced apoptosis in the cancer cells by itself through upregulation of TRAIL and its death receptors. The presence of TNF significantly lowered CCN1 expression and its capability in apoptosis induction. Furthermore, we found that CCN1 boosted ADAM17-mediated cleavage of TNF receptors through ITGA11 and the soluble decoy receptors generated by this action neutralized TNF activity. Taken together, CCN1 and TNF antagonize each other in esophageal cancer cells.

sTNFRII-Fc modification protects human UC-MSCs against apoptosis/autophagy induced by TNF-α and enhances their efficacy in alleviating inflammatory arthritis

BACKGROUND

Tumor necrosis factor (TNF)-α inhibitors represented by Etanercept (a fusion protein containing soluble TNF receptor II (sTNFRII) and the Fc segment of human IgG1) play a pivotal role in Rheumatoid arthritis (RA) treatment. However, long-term use increases the risk of infection and tumors for their systemic inhibition of TNF-α, which disrupts the regular physiological function of this molecular. Mesenchymal stem cells (MSCs)-based delivery system provides new options for RA treatment with their "homing" and immune-regulation capacities, whereas inflammatory environment (especially TNF-α) is not conducive to MSCs' therapeutic effects by inducing apoptosis/autophagy. Here, we constructed a strain of sTNFRII-Fc-expressing MSCs (sTNFRII-MSC), aiming to offset the deficiency of those two interventions.

METHODS

Constructed sTNFRII-Fc lentiviral vector was used to infect human umbilical cord-derived MSCs, and sTNFRII-MSC stable cell line was generated by monoclonal cultivation. In vitro and vivo characteristics of sTNFRII-MSC were assessed by coculture assay and an acute inflammatory model in NOD/SCID mice. The sTNFRII-MSC were transplanted into CIA model, pathological and immunological indicators were detected to evaluate the therapeutic effects of sTNFRII-MSC. The distribution of sTNFRII-MSC was determined by immunofluorescence assay. Apoptosis and autophagy were analyzed by flow cytometry, western blot and immunofluorescence.

RESULTS

sTNFRII-Fc secreted by sTNFRII-MSC present biological activity both in vitro and vivo. sTNFRII-MSC transplantation effectively alleviates mice collagen-induced arthritis (CIA) via migrating to affected area, protecting articular cartilage destruction, modulating immune balance and sTNFRII-MSC showed prolonged internal retention via resisting apoptosis/autophagy induced by TNF-α.

CONCLUSION

sTNFRII-Fc modification protects MSCs against apoptosis/autophagy induced by TNF-α, in addition to releasing sTNFRII-Fc neutralizing TNF-α to block relevant immune-inflammation cascade, and thus exert better therapeutic effects in alleviating inflammatory arthritis.

ADAM17 orchestrates Interleukin-6, TNFα and EGF-R signaling in inflammation and cancer

It was realized in the 1990s that some membrane proteins such as TNFα, both TNF receptors, ligands of the EGF-R and the Interleukin-6 receptor are proteolytically cleaved and are shed from the cell membrane as soluble proteins. The major responsible protease is a metalloprotease named ADAM17. So far, close to 100 substrates, including cytokines, cytokine receptors, chemokines and adhesion molecules of ADAM17 are known. Therefore, ADAM17 orchestrates many different signaling pathways and is a central signaling hub in inflammation and carcinogenesis. ADAM17 plays an important role in the biology of Interleukin-6 (IL-6) since the generation of the soluble Interleukin-6 receptor (sIL-6R) is needed for trans-signaling, which has been identified as the pro-inflammatory activity of this cytokine. In contrast, Interleukin-6 signaling via the membrane-bound Interleukin-6 receptor is mostly regenerative and protective. Probably due to its broad substrate spectrum, ADAM17 is essential for life and most of the few human individuals identified with ADAM17 gene defects died at young age. Although the potential of ADAM17 as a therapeutic target has been recognized, specific blockade of ADAM17 is not trivial since the metalloprotease domain of ADAM17 shares high structural homology with other proteases, in particular matrix metalloproteases. Here, the critical functions of ADAM17 in IL-6, TNFα and EGF-R pathways and strategies of therapeutic interventions are discussed.

Extracellular Matrix-Induced GM-CSF and Hypoxia Promote Immune Control of Mycobacterium tuberculosis in Human In Vitro Granulomas

Several in vitro cellular models have been developed with the aim to reproduce and dissect human granulomatous responses, the hallmark of tuberculosis (TB) immunopathogenesis. In that context, we compared two- (2D) versus three-dimensional (3D) granuloma models resulting from infection of human peripheral blood mononuclear cells with M. tuberculosis (Mtb) in the absence or presence of a collagen-based extracellular matrix (ECM). Granuloma formation was found to be significantly enhanced in the 2D model. This feature was associated with an earlier chemokine production and lymphocyte activation, but also a significantly increased bacterial burden. Remarkably, the reduction in Mtb burden in the 3D model correlated with an increase in GM-CSF production. GM-CSF, which is known to promote macrophage survival, was found to be inherently induced by the ECM. We observed that only 3D in vitro granulomas led to the accumulation of lipid inclusions within Mtb. Our data suggest that a hypoxic environment within the ECM could be responsible for this dormant-like Mtb phenotype. Furthermore, exposure to a TNF-α antagonist reverted Mtb dormancy, thereby mimicking the reactivation of TB observed in rheumatic patients receiving this therapy. To conclude, we showed that only in vitro granulomas generated in the presence of an ECM could recapitulate some clinically relevant features of granulomatous responses in TB. As such, this model constitutes a highly valuable tool to study the interplay between immunity and Mtb stress responses as well as to evaluate novel treatment strategies.

Molecular mechanism and therapeutic targeting of necrosis, apoptosis, pyroptosis, and autophagy in cardiovascular disease

ABSTRACT

Cell death occurs in various tissues and organs in the body. It is a physiological or pathological process that has different effects. It is of great significance in maintaining the morphological function of cells and clearing abnormal cells. Pyroptosis, apoptosis, and necrosis are all modes of cell death that have been studied extensively by many experts and scholars, including studies on their effects on the liver, kidney, the heart, other organs, and even the whole body. The heart, as the most important organ of the body, should be a particular focus. This review summarizes the mechanisms underlying the various cell death modes and the relationship between the various mechanisms and heart diseases. The current research status for heart therapy is discussed from the perspective of pathogenesis.

Analysis of miRNAs Profiles in Serum of Patients With Steatosis and Steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) is emerging as one of the most common chronic liver diseases worldwide, affecting 25% of the world population. In recent years, there has been increasing evidence for the involvement of microRNAs in the epigenetic regulation of genes taking part in the development of steatosis and steatohepatitis—two main stages of NAFLD pathogenesis. In the present study, miRNA profiles were studied in groups of patients with steatosis and steatohepatitis to compare the characteristics of RNA-dependent epigenetic regulation of the stages of NAFLD development. According to the results of miRNA screening, 23 miRNAs were differentially expressed serum in a group of patients with steatohepatitis and 2 in a group of patients with steatosis. MiR-195-5p and miR-16-5p are common differentially expressed miRNAs for both steatosis and steatohepatitis. We analyzed the obtained results: the search for target genes for the differentially expressed miRNAs in our study and the subsequent gene set enrichment analysis performed on KEGG and REACTOME databases revealed which metabolic pathways undergo changes in RNA-dependent epigenetic regulation in steatosis and steatohepatitis. New findings within the framework of this study are the dysregulation of neurohumoral pathways in the pathogenesis of NAFLD as an object of changes in RNA-dependent epigenetic regulation. The miRNAs differentially expressed in our study were found to target 7% of genes in the classic pathogenesis of NAFLD in the group of patients with steatosis and 50% in the group of patients with steatohepatitis. The effects of these microRNAs on genes for the pathogenesis of NAFLD were analyzed in detail. MiR-374a-5p, miR-1-3p and miR-23a-3p do not target genes directly involved in the pathogenesis of NAFLD. The differentially expressed miRNAs found in this study target genes largely responsible for mitochondrial function. The role of miR-423-5p, miR-143-5p and miR-200c-3 in regulating apoptotic processes in the liver and hepatocarcinogenesis is of interest for future experimental studies. These miR-374a, miR-143, miR-1, miR-23a, and miR-423 have potential for steatohepatitis diagnosis and are poorly studied in the context of NAFLD. Thus, this work opens up prospects for further studies of microRNAs as diagnostic and therapeutic biomarkers for NAFLD.

Tumor Necrosis Factor-alpha utilizes MAPK/NFκB pathways to induce cholesterol-25 hydroxylase for amplifying pro-inflammatory response via 25-hydroxycholesterol-integrin-FAK pathway

Exaggerated inflammatory response results in pathogenesis of various inflammatory diseases. Tumor Necrosis Factor-alpha (TNF) is a multi-functional pro-inflammatory cytokine regulating a wide spectrum of physiological, biological, and cellular processes. TNF induces Focal Adhesion Kinase (FAK) for various activities including induction of pro-inflammatory response. The mechanism of FAK activation by TNF is unknown and the involvement of cell surface integrins in modulating TNF response has not been determined. In the current study, we have identified an oxysterol 25-hydroxycholesterol (25HC) as a soluble extracellular lipid amplifying TNF mediated innate immune pro-inflammatory response. Our results demonstrated that 25HC-integrin-FAK pathway amplifies and optimizes TNF-mediated pro-inflammatory response. 25HC generating enzyme cholesterol 25-hydroxylase (C25H) was induced by TNF via NFκB and MAPK pathways. Specifically, chromatin immunoprecipitation assay identified binding of AP-1 (Activator Protein-1) transcription factor ATF2 (Activating Transcription Factor 2) to the C25H promoter following TNF stimulation. Furthermore, loss of C25H, FAK and α5 integrin expression and inhibition of FAK and α5β1 integrin with inhibitor and blocking antibody, respectively, led to diminished TNF-mediated pro-inflammatory response. Thus, our studies show extracellular 25HC linking TNF pathway with integrin-FAK signaling for optimal pro-inflammatory activity and MAPK/NFκB-C25H-25HC-integrin-FAK signaling network playing an essential role to amplify TNF dependent pro-inflammatory response. Thus, we have identified 25HC as the key factor involved in FAK activation during TNF mediated response and further demonstrated a role of cell surface integrins in positively regulating TNF dependent pro-inflammatory response.

Accelerated Discovery of Potent Bioactive anti-TNFα Aptamers by Microbead-Assisted Capillary Electrophoresis (MACE)-SELEX

Dysregulation of tumor necrosis factor-α (TNFα), a pro-inflammatory cytokine, causes several diseases, making it an important therapeutic target. Here, we identified a novel DNA aptamer against human TNFα using in vitro selection, which included a high exclusion pressure process against non-binding and weak binders through microbead-assisted capillary electrophoresis (MACE) in only three rounds. Among the 15 most enriched aptamers, Apt14 exhibited the highest inhibitory activity for the interaction between TNFα and its cognate receptor in mouse L929 cells. For further improving the bioactivity of the aptamer, dimerization programed by hybridization was evaluated, resulting in the Apt14 dimer exhibited a twofold higher binding affinity and stronger inhibition compared to the monomer counterpart. Rapid identification of bioactive aptamers using MACE in combination with facile dimerization by hybridization accelerates the discovery of novel bioactive aptamers, paving the way toward replacing current monoclonal antibody therapy with the less expensive and non-immunogenic aptamer therapy.

Lymphopenia Caused by Virus Infections and the Mechanisms Beyond

Viral infections can give rise to a systemic decrease in the total number of lymphocytes in the blood, referred to as lymphopenia. Lymphopenia may affect the host adaptive immune responses and impact the clinical course of acute viral infections. Detailed knowledge on how viruses induce lymphopenia would provide valuable information into the pathogenesis of viral infections and potential therapeutic targeting. In this review, the current progress of viruses-induced lymphopenia is summarized and the potential mechanisms and factors involved are discussed.

Evaluation and Validation of the Prognostic Value of Serum Albumin to Globulin Ratio in Patients With Cancer Cachexia: Results From a Large Multicenter Collaboration

BACKGROUND

Recently, albumin-globulin ratio (AGR), a serological indicator that reflects nutritional status and systemic inflammatory, has been reported to be associated with the prognosis of various cancers. However, there is currently no research report on its relationship with cancer cachexia.

OBJECTIVES

This study aimed to explore the prognostic value of AGR in patients with cancer cachexia through a multicenter retrospective analysis.

METHODS

We recruited 2,364 patients with cancer cachexia and randomly divided the patients into training and validation cohorts at a ratio of 7:3. The optimal stratification method was used to determine the optimal cutoff value of AGR. The survival curve was evaluated by the Kaplan-Meier method. Cox regression proportional-hazards model was used to determine independent prognostic factors in patients with cancer cachexia. The time-dependent receiver operating characteristic curve was used to compare the prognostic performance of different malnutrition evaluation tools.

RESULTS

The optimal cutoff value of AGR is 1.24 in patients with cancer cachexia. Increasing AGR was associated with survival in a dose-response manner with a forward L-shape. Compared with the high AGR group, the low AGR group had a shorter overall survival; and there was consistency in training and validation cohorts. In the stratified analysis of TNM stage, AGR has good prognostic distinguishing ability for advanced patients. Multivariate survival analysis determined that low AGR was an independent risk factor affecting all-cause mortality in patients with cancer cachexia. In addition, compared with other malnutrition evaluation tools, AGR could effectively stratify the prognosis of patients with cancer cachexia.

CONCLUSION

AGR was an independent prognostic factor affecting patients with cancer cachexia, especially in advanced patients. Compared with other malnutrition evaluation tools, AGR can effectively stratify the prognosis of patients with cancer cachexia.

Function of Protein S-Palmitoylation in Immunity and Immune-Related Diseases

Protein S-palmitoylation is a covalent and reversible lipid modification that specifically targets cysteine residues within many eukaryotic proteins. In mammalian cells, the ubiquitous palmitoyltransferases (PATs) and serine hydrolases, including acyl protein thioesterases (APTs), catalyze the addition and removal of palmitate, respectively. The attachment of palmitoyl groups alters the membrane affinity of the substrate protein changing its subcellular localization, stability, and protein-protein interactions. Forty years of research has led to the understanding of the role of protein palmitoylation in significantly regulating protein function in a variety of biological processes. Recent global profiling of immune cells has identified a large body of S-palmitoylated immunity-associated proteins. Localization of many immune molecules to the cellular membrane is required for the proper activation of innate and adaptive immune signaling. Emerging evidence has unveiled the crucial roles that palmitoylation plays to immune function, especially in partitioning immune signaling proteins to the membrane as well as to lipid rafts. More importantly, aberrant PAT activity and fluctuations in palmitoylation levels are strongly correlated with human immunologic diseases, such as sensory incompetence or over-response to pathogens. Therefore, targeting palmitoylation is a novel therapeutic approach for treating human immunologic diseases. In this review, we discuss the role that palmitoylation plays in both immunity and immunologic diseases as well as the significant potential of targeting palmitoylation in disease treatment.

8-Geranylumbelliferone isolated from Paramignya trimera triggers RIPK1/RIPK3-dependent programmed cell death upon TNFR1 ligation

In tumor necrosis factor (TNF) signaling, IκB kinase (IKK) complex-mediated activation of NF-κB is a well-known protective mechanism against cell death via transcriptional induction of pro-survival genes occurring as a late checkpoint. However, recent belief holds that IKK functions as an early cell death checkpoint to suppress the death-inducing signaling complex by regulating receptor interacting protein kinase1 (RIPK1) phosphorylation. In this study, we propose that two major gernaylated 7-hydroxy coumarins, 6-geranyl-7-hydroxycoumarin (ostruthin) and 8-geranyl-7-hydroxycoumarin (8-geranylumbelliferone, 8-GU) isolated from Paramignya timera, facilitate RIPK1-dependent dual modes of apoptosis and necroptosis by targeting IKKβ upon TNF receptor1 (TNFR1) ligation. Analysis of events upstream of NF-κB revealed that 8-GU and ostruthin drastically inhibited TNF-induced IKK phosphorylation, while having no effect on TAK1 phosphorylation and TNFR1 complex-I formation. Interestingly, 8-GU did not affect the cell death induced by Fas ligand or TNF-related apoptosis-inducing ligand or that induced by DNA-damaging agents, indicating that 8-GU sensitizes TNF-induced cell death exclusively. Moreover, 8-GU accelerated TNF-driven necroptosis by up-regulating necrosome formation in FADD deficient cancer cells harboring RIPK3. Thus, the present study provides new insights into the molecular mechanism underlying geranylated 7-hydroxy coumarin-mediated control of the RIPK1-dependent early cell death checkpoint and suggests that 8-GU is a potential anti-cancer therapeutic via an alternative apoptosis-independent strategy to overcome TNF resistance.

Ferroptosis: A Trigger of Proinflammatory State Progression to Immunogenicity in Necroinflammatory Disease

Until recently, necrosis is generally regarded as traumatic cell death due to mechanical shear stress or other physicochemical factors, while apoptosis is commonly thought to be programmed cell death, which is silent to immunological response. Actually, multiple modalities of cell death are programmed to maintain systematic immunity. Programmed necrosis, such as necrosis, pyroptosis, and ferroptosis, are inherently more immunogenic than apoptosis. Programmed necrosis leads to the release of inflammatory cytokines, defined as danger-associated molecular patterns (DAMPs), resulting in a necroinflammatory response, which can drive the proinflammatory state under certain biological circumstances. Ferroptosis as a newly discovered non-apoptotic form of cell death, is characterized by excessive lipid peroxidation and overload iron, which occurs in cancer, neurodegeneration, immune and inflammatory diseases, as well as ischemia/reperfusion (I/R) injury. It is triggered by a surplus of reactive oxygen species (ROS) induced in an imbalanced redox reaction due to the decrease in glutathione synthesis and inaction of enzyme glutathione peroxidase 4 (GPX4). Ferroptosis is considered as a potential therapeutic and molecular target for the treatment of necroinflammatory disease, and further investigation into the underlying pathophysiological characteristics and molecular mechanisms implicated may lay the foundations for an interventional therapeutic strategy. This review aims to demonstrate the key roles of ferroptosis in the development of necroinflammatory diseases, the major regulatory mechanisms involved, and its potential as a therapeutic target.

Interactions Between Specific Immune Status of Pregnant Women and SARS-CoV-2 Infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the pathogen responsible for the Coronavirus Disease 2019 (COVID-19) global pandemic. Because it is a new and highly contagious coronavirus, most people, especially pregnant women, lack immunity. It is therefore important to understand the interaction between why pregnant women are susceptible to SARS-CoV-2 and the specific immune systems of pregnant women. Here, we provide an overview of the changes that occur in the immune system during pregnancy, the activation and response of the immune system in pregnant women with COVID-19, adverse pregnancy outcomes in pregnant women with COVID-19, and the treatment and prevention of COVID-19 in this population.

Apoptotic Pathways and Alzheimer's Disease: Probing Therapeutic Potential

Apoptosis is an intrinsic biochemical, cellular process that regulates cell death and is crucial for cell survival, cellular homeostasis, and maintaining the optimum functional status. Apoptosis in a predetermined and programmed manner regulates several molecular events, including cell turnover, embryonic development, and immune system functions but may be the exclusive contributor to several disorders, including neurodegenerative manifestations, when it functions in an aberrant and disorganized manner. Alzheimer's disease (AD) is a fatal, chronic neurodegenerative disorder where apoptosis has a compelling and divergent role. The well-characterized pathological features of AD, including extracellular plaques of amyloid-beta, intracellular hyperphosphorylated tangles of tau protein (NFTs), inflammation, mitochondrial dysfunction, oxidative stress, and excitotoxic cell death, also instigate an abnormal apoptotic cascade in susceptible brain regions (cerebral cortex, hippocampus). The apoptotic players in these regions affect cellular organelles (mitochondria and endoplasmic reticulum), interact with trophic factors, and several pathways, including PI3K/AKT, JNK, MAPK, mTOR signalling. This dysregulated apoptotic cascade end with an abnormal neuronal loss which is a primary event that may precede the other events of AD progression and correlates well with the degree of dementia. The present review provides insight into the diverse and versatile apoptotic mechanisms that are indispensable for neuronal survival and constitute an integral part of the pathological progression of AD. Identification of potential targets (restoring apoptotic and antiapoptotic balance, caspases, TRADD, RIPK1, FADD, TNFα, etc.) may be valuable and advantageous to decide the fate of neurons and to develop potential therapeutics for treatment of AD.

Caspase-8 mutations associated with head and neck cancer differentially retain functional properties related to TRAIL-induced apoptosis and cytokine induction

The cysteine protease, caspase-8, undergoes dimerization, processing, and activation following stimulation of cells with death ligands such as TRAIL, and mediates TRAIL induction of the extrinsic apoptosis pathway. In addition, caspase-8 mediates TRAIL-induced activation of NF-κB and upregulation of immunosuppressive chemokines/cytokines, via a mechanism independent of caspase-8 catalytic activity. The gene encoding procaspase-8 is mutated in 10% of human head and neck squamous cell carcinomas (HNSCCs). Despite a paucity of experimental evidence, HNSCC-associated caspase-8 mutations are commonly assumed to be loss of function. To investigate their functional properties and phenotypic effects, 18 HNSCC-associated caspase-8 mutants were expressed in doxycycline-inducible fashion in cell line models wherein the endogenous wild-type caspase-8 was deleted. We observed that 5/8 mutants in the amino-terminal prodomain, but 0/10 mutants in the carboxyl-terminal catalytic region, retained an ability to mediate TRAIL-induced apoptosis. Caspase-8 proteins with mutations in the prodomain were defective in dimerization, whereas all ten of the catalytic region mutants efficiently dimerized, revealing an inverse relationship between dimerization and apoptosis induction for the mutant proteins. Roughly half (3/8) of the prodomain mutants and 9/10 of the catalytic region mutants retained the ability to mediate TRAIL induction of immunosuppressive CXCL1, IL-6, or IL-8. Doxycycline-induced expression of wild-type caspase-8 or a representative mutant led to an increased percentage of T and NKT cells in syngeneic HNSCC xenograft tumors. These findings demonstrate that HNSCC-associated caspase-8 mutants retain properties that may influence TRAIL-mediated apoptosis and cytokine induction, as well as the composition of the tumor microenvironment.