Microbiota promotes systemic T-cell survival through suppression of an apoptotic factor

The microbiota and T cells non-genetically modulate inherited phenotypes transgenerationally

The host-microbiota relationship has evolved to shape mammalian physiology, including immunity, metabolism, and development. Germ-free models are widely used to study microbial effects on host processes such as immunity. Here, we find that both germ-free and T cell-deficient mice exhibit a robust sebum secretion defect persisting across multiple generations despite microbial colonization and T cell repletion. These phenotypes are inherited by progeny conceived during in vitro fertilization using germ-free sperm and eggs, demonstrating that non-genetic information in the gametes is required for microbial-dependent phenotypic transmission. Accordingly, gene expression in early embryos derived from gametes from germ-free or T cell-deficient mice is strikingly and similarly altered. Our findings demonstrate that microbial- and immune-dependent regulation of non-genetic information in the gametes can transmit inherited phenotypes transgenerationally in mice. This mechanism could rapidly generate phenotypic diversity to enhance host adaptation to environmental perturbations.

The roles of lncRNAs and miRNAs in pancreatic cancer: a focus on cancer development and progression and their roles as potential biomarkers

Pancreatic ductal adenocarcinoma (PDAC) is among the most penetrative malignancies affecting humans, with mounting incidence prevalence worldwide. This cancer is usually not diagnosed in the early stages. There is also no effective therapy against PDAC, and most patients have chemo-resistance. The combination of these factors causes PDAC to have a poor prognosis, and often patients do not live longer than six months. Because of the failure of conventional therapies, the identification of key biomarkers is crucial in the early diagnosis, treatment, and prognosis of pancreatic cancer. 65% of the human genome encodes ncRNAs. There are different types of ncRNAs that are classified based on their sequence lengths and functions. They play a vital role in replication, transcription, translation, and epigenetic regulation. They also participate in some cellular processes, such as proliferation, differentiation, metabolism, and apoptosis. The roles of ncRNAs as tumor suppressors or oncogenes in the growth of tumors in a variety of tissues, including the pancreas, have been demonstrated in several studies. This study discusses the key roles of some lncRNAs and miRNAs in the growth and advancement of pancreatic carcinoma. Because they are involved not only in the premature identification, chemo-resistance and prognostication, also their roles as potential biomarkers for better management of PDAC patients.

Erdr1 Drives Macrophage Programming via Dynamic Interplay with YAP1 and Mid1

Erythroid differentiation regulator 1 (Erdr1) is a stress-induced, widely expressed, highly conserved secreted factor found in both humans and mice. Erdr1 is linked with the Hippo-YAP1 signaling. Initially identified as an inducer of hemoglobin synthesis, Erdr1 emerged as a multifunctional protein, especially in immune cells. Although Erdr1 has been implicated in regulating T cells and NK cell function, its role in macrophage remains unclear. This study explored the function and mechanism of Erdr1 in macrophage inflammatory response. The data demonstrated that Erdr1 could promote anti-inflammatory cytokine production, a function that also has been reported by previous research. However, I found Erdr1 also could play a proinflammatory role. The function of Erdr1 in macrophages depends on its dose and cell density. I observed that Erdr1 expression was inhibited in M1 macrophages but was upregulated in M2 macrophages compared with unpolarized macrophages. I hypothesized that Erdr1 balances the inflammatory response by binding with distinct adaptors dependent on varying concentrations. Mechanistically, I demonstrated YAP1 and Mid1 as the two adaptor proteins of Erdr1. The Erdr1-YAP1 interaction promotes anti-inflammatory cytokine production when Erdr1 levels are elevated, whereas the Erdr1-Mid1 interaction induces proinflammatory cytokine production when Erdr1 levels are decreased. This study highlights the effects of Erdr1 on regulating cytokine production from polarized macrophages potentially by regulating YAP1 in the nonclassical Hippo pathway.

Erdr1 orchestrates macrophage polarization and determines cell fate via dynamic interplay with YAP1 and Mid1

Erythroid differentiation regulator 1 (Erdr1) is a stress-induced, widely distributed, extremely conserved secreted factor found in both humans and mice. Erdr1 is highly linked with the Hippo-YAP1 signaling. Initially identified as an inducer of hemoglobin synthesis, it has emerged as a multifunctional protein, especially in immune cells. Although Erdr1 has been implicated in T cells and NK cell function, its role in macrophage remains unclear. This study aims to explore the function and mechanism of Erdr1 in IL-1β production in macrophages. Data manifest Erdr1 could play an inhibition role in IL-1β production, which also has been reported by previous research. What significance is we discovered Erdr1 can promote IL-1β production which is associated with Erdr1 dose and cell density. We observed that Erdr1 was inhibited in pro-inflammatory (M1) macrophages but was upregulated in anti-inflammatory (M2) macrophages compared to naive macrophages. We hypothesized that Erdr1 dual drives and modulates IL-1β production by binding with distinct adaptors via concentration change. Mechanistically, we demonstrated that Erdr1 dual regulates IL-1β production by dynamic interaction with YAP1 and Mid1 by distinct domains. Erdr1-YAP1 interplay mediates macrophage M2 polarization by promoting an anti-inflammatory response, enhancing catabolic metabolism, and leading to sterile cell death. Whereas, Erdr1-Mid1 interplay mediates macrophage M1 polarization by initiating a pro-inflammatory response, facilitating anabolic metabolism, and causing inflammatory cell death. This study highlights Erdr1 orchestrates macrophage polarization and determines cell date by regulating YAP1 through non-classical Hippo pathway.

IL-24 is the key effector of Th9 cell-mediated tumor immunotherapy

Th9 cells are powerful effector T cells for cancer immunotherapy. However, the underlying antitumor mechanism of Th9 cells still needs to be further elucidated. Here, we show that Th9 cells express high levels of not only IL-9, but also IL-24. We found that knockout of Il24 gene in Th9 cells promotes Th9 cell proliferation in vitro, but decreases Th9 cell survival in vitro and in vivo. Interestingly, knockout of Il24 gene in Th9 cells decreases the tumor-specific cytotoxicity of Th9 cells in vitro. In addition, immunotherapy with Il24 knockout Th9 cells exhibit less tumor inhibition than regular Th9 cells in mouse tumor models. We found that inhibition of Foxo1 by a specific inhibitor downregulates IL-24 expression in Th9 cells and decreases Th9 cell antitumor efficacy in vivo. Our results identify IL-24 as a powerful antitumor effector of Th9 cells and provide a target in Th9 cell-mediated tumor therapy.

Endothelial-specific loss of IKKβ disrupts pulmonary endothelial angiogenesis and impairs postnatal lung growth

Pulmonary angiogenesis drives alveolarization, but the transcriptional regulators directing pulmonary angiogenesis remain poorly defined. Global, pharmacological inhibition of nuclear factor-kappa B (NF-κB) impairs pulmonary angiogenesis and alveolarization. However, establishing a definitive role for NF-κB in pulmonary vascular development has been hindered by embryonic lethality induced by constitutive deletion of NF-κB family members. We created a mouse model allowing inducible deletion of the NF-κB activator, IKKβ, in endothelial cells (ECs) and assessed the effect on lung structure, endothelial angiogenic function, and the lung transcriptome. Embryonic deletion of IKKβ permitted lung vascular development but resulted in a disorganized vascular plexus, while postnatal deletion significantly decreased radial alveolar counts, vascular density, and proliferation of both endothelial and nonendothelial lung cells. Loss of IKKβ impaired survival, proliferation, migration, and angiogenesis in primary lung ECs in vitro, in association with decreased expression of VEGFR2 and activation of downstream effectors. Loss of endothelial IKKβ in vivo induced broad changes in the lung transcriptome with downregulation of genes related to mitotic cell cycle, extracellular matrix (ECM)-receptor interaction, and vascular development, and the upregulation of genes related to inflammation. Computational deconvolution suggested that loss of endothelial IKKβ decreased general capillary, aerocyte capillary, and alveolar type I cell abundance. Taken together, these data definitively establish an essential role for endogenous endothelial IKKβ signaling during alveolarization. A deeper understanding of the mechanisms directing this developmental, physiological activation of IKKβ in the lung vasculature may provide novel targets for the development of strategies to enhance beneficial proangiogenic signaling in lung development and disease.NEW & NOTEWORTHY This study highlights the cell-specific complexity of nuclear factor kappa B signaling in the developing lung by demonstrating that inducible loss of IKKβ in endothelial cells impairs alveolarization, disrupts EC angiogenic function, and broadly represses genes important for vascular development.

The microbiota and immune system non-genetically affect offspring phenotypes transgenerationally

The host-microbiota relationship has evolved to shape mammalian processes, including immunity, metabolism, and development 1-3 . Host phenotypes change in direct response to microbial exposures by the individual. Here we show that the microbiota induces phenotypic change not only in the individual but also in their succeeding generations of progeny. We found that germ-free mice exhibit a robust sebum secretion defect and transcriptional changes in various organs, persisting across multiple generations despite microbial colonization and breeding with conventional mice. Host-microbe interactions could be involved in this process, since T cell-deficient mice, which display defective sebum secretion 4 , also transgenerationally transmit their phenotype to progeny. These phenotypes are inherited by progeny conceived during in vitro fertilization using germ-free sperm and eggs, demonstrating that epigenetic information in the gametes is required for phenotypic transmission. Accordingly, small non-coding RNAs that can regulate embryonic gene expression 5 were strikingly and similarly altered in gametes of germ-free and T cell-deficient mice. Thus, we have uncovered a novel mechanism whereby the microbiota and immune system induce phenotypic changes in successive generations of offspring. This epigenetic form of inheritance could be advantageous for host adaptation to environmental perturbation, where phenotypic diversity can be introduced more rapidly than by genetic mutation.

Disequilibrium in the Thioredoxin Reductase-1/Thioredoxin-1 Redox Couple Is Associated with Increased T-Cell Apoptosis in Children with Autism

Autism spectrum disorder (ASD) is a neuropsychiatric childhood disorder that affects social skill and language development, and is characterized by persistent stereotypic behaviors, restricted social interests, and impaired language/social skills. ASD subjects have dysregulated immune responses due to impairment in inflammatory and antioxidant signaling in immune cells, such as T cells. Thioredoxin reductase-1 (TrxR1) and thioredoxin-1 (Trx1) play a crucial role in the maintenance of redox equilibrium in several immune cells, including T cells. T-cell apoptosis plays a crucial role in the pathogenesis of several inflammatory diseases. However, it remains to be explored how the TrxR1/Trx1 redox couple affects T-cells apoptosis in ASD and typically developing control (TDC) groups. Therefore, this single-center cross-sectional study explored the expression/activity of TrxR1/Trx1, and Bcl2, 7-AAD/annexin V immunostaining in T cells of ASD (n = 25) and TDC (n = 22) groups. Further, effects of the LPS were determined on apoptosis in TDC and ASD T cells. Our data show that T cells have increased TrxR1 expression, while having decreased Trx1 expression in the ASD group. Further, TrxR enzymatic activity was also elevated in T cells of the ASD group. Furthermore, T cells of the ASD group had a decreased Bcl2 expression and an increased % of annexin V immunostaining. Treatment of T cells with LPS caused greater apoptosis in the ASD group than the TDC group, with same treatment. These data reveal that the redox couple TrxR1/Trx1 is dysregulated in T cells of ASD subjects, which is associated with decreased Bcl2 expression and increased apoptosis. This may lead to decreased survival of T cells in ASD subjects during chronic inflammation. Future studies should investigate environmental factors, such as gut dysbiosis and pollutants, that may cause abnormal immune responses in the T cells of ASD subjects due to chronic inflammation.

Exploring the cellular landscape of circular RNAs using full-length single-cell RNA sequencing

Previous studies have demonstrated the highly specific expression of circular RNAs (circRNAs) in different tissues and organisms, but the cellular architecture of circRNA has never been fully characterized. Here, we present a collection of 171 full-length single-cell RNA-seq datasets to explore the cellular landscape of circRNAs in human and mouse tissues. Through large-scale integrative analysis, we identify a total of 139,643 human and 214,747 mouse circRNAs in these scRNA-seq libraries. We validate the detected circRNAs with the integration of 11 bulk RNA-seq based resources, where 216,602 high-confidence circRNAs are uniquely detected in the single-cell cohort. We reveal the cell-type-specific expression pattern of circRNAs in brain samples, developing embryos, and breast tumors. We identify the uniquely expressed circRNAs in different cell types and validate their performance in tumor-infiltrating immune cell composition deconvolution. This study expands our knowledge of circRNA expression to the single-cell level and provides a useful resource for exploring circRNAs at this unprecedented resolution.

Studies of circular RNAs have often been limited to the tissue or organism level. Here, authors investigate the comprehensive expression landscape of circRNAs in human and mouse at single-cell resolution, revealing highly specific and dynamic changes of circRNAs during multiple biological processes.

Erythroid Differentiation Regulator 1 Ameliorates Collagen-Induced Arthritis via Activation of Regulatory T Cells

Erythroid differentiation regulator 1 (Erdr1) has been identified as an anti-inflammatory factor in several disease models, including collagen-induced arthritis (CIA), but its exact mechanisms are still not fully understood. Here, the involvement of regulatory T (Treg) cells in Erdr1-improved CIA was investigated. In the CIA model, Erdr1 was confirmed to reduce collagen-specific IgM in plasma and plasma cells in draining lymph nodes. Importantly, the downregulated Treg cell ratio in draining lymph nodes from CIA mice was recovered by Erdr1 treatment. In addition, administration of Erdr1 improved the CIA score and joint tissue damage, while it revealed no effect in Treg cell-depleted CIA mice, indicating that Treg cells mediate the therapeutic effects of Erdr1 in the CIA model. Results from in vitro experiments also demonstrated that Erdr1 significantly induced Treg cell differentiation and the expression of Treg activation markers, including CD25, CD69, and CTLA4 in CD4⁺Foxp3⁺ cells. Furthermore, Erdr1-activated Treg cells dramatically suppressed the proliferation of responder T cells, suggesting that they are functionally active. Taken together, these results show that Erdr1 induces activation of Treg cells and ameliorates rheumatoid arthritis via Treg cells.

Erythroid differentiation regulator 1 promotes wound healing by inducing the production of C‑C motif chemokine ligand 2 via the activation of MAP kinases in vitro and in vivo

The erythroid differentiation regulator 1 (Erdr1) protein has been studied for its role in various inflammatory skin diseases, including skin cancer, actinic keratosis and psoriasis. However, the therapeutic effects of Erdr1 on wound repair and its underlying mechanisms remain unknown. The present study aimed to investigate the effects of Erdr1 on wound healing in vitro and in vivo. The results demonstrated that treatment with recombinant Erdr1 enhanced wound healing in vivo and in vitro. In addition, Erdr1 increased the proliferation and migration of human dermal fibroblasts (HDFs). Notably, Erdr1 significantly induced the production of the chemoattractant C-C motif chemokine ligand 2 (CCL2) and recruited immune cells involved in wound healing. Treatment with recombinant Erdr1 induced the activation of the ERK1/1, p38 and JNK1/2 mitogen-activated protein (MAP) kinases. Treatment with specific inhibitors for MAP kinase inhibitors markedly suppressed cell proliferation and migration, and inhibited the production of CCL2 in HDFs. Furthermore, the inhibition of CCL2 with a neutralizing antibody significantly suppressed the recombinant Erdr1-induced proliferation and migration of HDFs. The wound healing activity of Erdr1 was comparable to that of epidermal growth factor. Taken together, these results demonstrated that Erdr1 promoted the proliferation and migration of HDFs and exhibited potent wound healing properties mediated by CCL2. Therefore, the results of the present study suggested that Erdr1 may be a potential therapeutic target for promoting wound healing.

P2X7 Receptor Activity Limits Accumulation of T Cells within Tumors

Extracellular ATP (eATP) is a signaling molecule that variably affects all cells of the immune system either directly or after hydrolysis to adenosine. Although eATP is virtually absent in the interstitium of normal tissues, it can be present in the hundreds of micromolar range in tumors, a concentration compatible with activation of the ATP-gated ionotropic P2X7 receptor. Here, we show that P2X7 activity in tumor-infiltrating lymphocytes (TIL) induces cellular senescence and limits tumor suppression. P2X7 stimulation affected cell cycling of effector T cells and resulted in generation of mitochondrial reactive oxygen species and p38 MAPK-dependent upregulation of cyclin-dependent kinase inhibitor 1A (Cdkn1a, encoding for p21^Waf1/Cip1). Lack of P2X7 promoted a transcriptional signature that correlated with enhanced cytotoxic T-cell response in human solid tumors. In mice, transfer of tumor-specific T cells with deletion of P2rx7 significantly reduced tumor growth and extended survival. Collectively, these findings uncover a purinergic checkpoint that can be targeted to improve the efficacy of cancer immunotherapy strategies. SIGNIFICANCE: These findings suggest that the purinergic checkpoint P2X7 may be targeted to enhance T-cell-mediated cancer immunotherapy and improve T effector cell accumulation in the tumor microenvironment. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/18/3906/F1.large.jpg.

The Role of Erythroid Differentiation Regulator 1 (ERDR1) in the Control of Proliferation and Photodynamic Therapy (PDT) Response

Erythroid differentiation regulator 1 (ERDR1) was newly identified as a secreted protein that plays an essential role in maintaining cell growth homeostasis. ERDR1 enhances apoptosis at high cell densities, leading to the inhibition of cell survival. Exogenous ERDR1 treatment decreases cancer cell proliferation and tumor growth as a result of increased apoptosis via the regulation of apoptosis-related gene expression. Moreover, ERDR1 plays a pivotal role in skin diseases; ERDR1 expression in actinic keratosis (AK) is negatively correlated with the increase in apoptosis. Because of its high specificity and efficiency, photodynamic therapy (PDT) is a common therapy for patients with various skin diseases, including cancer. Many studies indicate that apoptosis is mainly induced by PDT treatment. As an apoptosis inducer, the recovery of the ERDR1 expression after PDT is correlated with good therapeutic outcomes. Here, we review recent findings that highlight the function of ERDR1 in the control of apoptosis. Thus, ERDR1 may have a role in the apoptosis regulation of target cells in the lesions, as the recovery of its expression after PDT is correlated with good therapeutic outcomes.

When Rhythms Meet the Blues: Circadian Interactions with the Microbiota-Gut-Brain Axis

The microbiota-gut-brain axis encompasses a bidirectional mode of communication between the microorganisms residing in our gut, and our brain function and behavior. The composition of the gut microbiota is subject to diurnal variation and is entrained by host circadian rhythms. In turn, a diverse microbiota is essential for optimal regulation of host circadian pathways. Disruption of the cyclical nature of this microbe-host interaction profoundly influences disease pathology and severity. This review aims to summarize current knowledge on this bidirectional relationship. Indeed, the past few years have revealed promising data regarding the relationship between the microbiota-gut-brain axis and circadian rhythms and how they act in concert to influence disease, but further research needs to be done to examine how they coalesce to modulate severity of, and risk for, certain diseases. Moreover, there is a need for a greater understanding of the molecular mechanisms underlying the close relationship between circadian-microbiome-brain interactions.

Erythroid differentiation regulator-1 induced by microbiota in early life drives intestinal stem cell proliferation and regeneration

Gut microbiota and their metabolites are instrumental in regulating intestinal homeostasis. However, early-life microbiota associated influences on intestinal development remain incompletely understood. Here we demonstrate that co-housing of germ-free (GF) mice with specific-pathogen free (SPF) mice at weaning (exGF) results in altered intestinal gene expression. Our results reveal that one highly differentially expressed gene, erythroid differentiation regulator-1 (Erdr1), is induced during development in SPF but not GF or exGF mice and localizes to Lgr5⁺ stem cells and transit amplifying (TA) cells. Erdr1 functions to induce Wnt signaling in epithelial cells, increase Lgr5⁺ stem cell expansion, and promote intestinal organoid growth. Additionally, Erdr1 accelerates scratch-wound closure in vitro, increases Lgr5⁺ intestinal stem cell regeneration following radiation-induced injury in vivo, and enhances recovery from dextran sodium sulfate (DSS)-induced colonic damage. Collectively, our findings indicate that early-life microbiota controls Erdr1-mediated intestinal epithelial proliferation and regeneration in response to mucosal damage.

Gut microbiota and their metabolites regulate homeostasis of the intestine, but their effects on intestine development are unclear. Here the authors use RNAseq and germ free mice to show that intestinal microbiota promote the expression of Erdr1, which increases Lgr5⁺ intestinal stem cell number and activity.

The microbiota protects from viral-induced neurologic damage through microglia-intrinsic TLR signaling

Symbiotic microbes impact the function and development of the central nervous system (CNS); however, little is known about the contribution of the microbiota during viral-induced neurologic damage. We identify that commensals aid in host defense following infection with a neurotropic virus through enhancing microglia function. Germfree mice or animals that receive antibiotics are unable to control viral replication within the brain leading to increased paralysis. Microglia derived from germfree or antibiotic-treated animals cannot stimulate viral-specific immunity and microglia depletion leads to worsened demyelination. Oral administration of toll-like receptor (TLR) ligands to virally infected germfree mice limits neurologic damage. Homeostatic activation of microglia is dependent on intrinsic signaling through TLR4, as disruption of TLR4 within microglia, but not the entire CNS (excluding microglia), leads to increased viral-induced clinical disease. This work demonstrates that gut immune-stimulatory products can influence microglia function to prevent CNS damage following viral infection.

Erythroid differentiation regulator 1 strengthens TCR signaling in thymocytes by modulating calcium flux

Erythroid differentiation regulator 1 (Erdr1) has been identified as a stromal survival factor released under stressful conditions. Previously, Erdr1 was reported to be expressed highly in thymus, but roles of Erdr1 in thymus were not known. Here, the effects of Erdr1 on T cell development were investigated. The expression of Erdr1 was higher in thymus than bone marrow and Erdr1 was detected in both the cortex and medulla of thymus. Erdr1 treatment significantly induced the expression of activation marker, CD69, from thymocytes in the presence of TCR stimuli in vitro and the induction was dependent on increased Ca²⁺ influx. In addition, in vivo administration of Erdr1 resulted in significant increase of total and positive selected thymocyte numbers, particularly in the number of CD3TCR^hiCD69⁺ DP thymocytes. Taken together, our results show that Erdr1 enhances the strength of TCR signaling and cellularity of thymocytes by amplifying Ca²⁺ influx in thymocytes receiving TCR signals.

Commensal regulation of T cell survival through Erdr1

The commensal microbiota influences many aspects of immune system regulation, including T cells, but molecular details of how this occurs are largely unknown. Here we review our findings that the microbiota regulates Erdr1, a secreted apoptotic factor, to control T cell survival. Erdr1 is highly upregulated in CD4+ T cells from germfree mice and antibiotic treated animals, and our study shows that Erdr1 is suppressed by the microbiota via Toll-like receptor signaling and MyD88 dependent pathways. Erdr1 functions in an autocrine fashion and promotes apoptosis through the FAS/FASL pathway. Suppression of Erdr1 leads to survival of autoreactive T cells and exacerbated autoimmune disease in the EAE model, and overexpression of Erdr1 results in lessened disease. This novel T cell apoptotic factor has implications for autoimmunity, cancer biology, and invasive pathogens and thus represents a novel therapeutic target in disease.