Neuronal signals have emerged as pivotal regulators of B cells that regulate antitumor immunity and tumor progression. However, the functional relevance and mechanistic basis of the effects of the neurotransmitter dopamine (DA) on tumor immunity remain elusive. Here, we discovered that plasma DA levels are positively correlated with circulating B cell numbers and potently activate B cell responses in a manner dependent on the DRD5 receptor. Notably, DRD5 signaling enhanced the Janus kinase 1 (JAK1)-STAT1 signaling in B cell responses, which enhanced B cell activation and increased antigen presentation and co-stimulation, resulting in increased expansion and cytotoxicity in tumor-specific effector of T cells. Our findings demonstrate that DA signaling suppresses tumor progression and highlight DRD5 as a promising target for cancer immunotherapy.

Memory CD8 + T cells play a crucial role in infection and cancer and mount rapid responses to repeat antigen exposure. Although memory cell transcriptional programmes have been previously identified, the regulatory mechanisms that control the formation of CD8 + T cells have not been resolved. Here we report ECSIT as an essential mediator of memory CD8 + T cell differentiation. Ablation of ECSIT in T cells resulted in loss of fumarate synthesis and abrogated TCF-1 expression via demethylation of the TCF-1 promoter by the histone demethylase KDM5, thereby impairing memory CD8 + T cell development in a cell-intrinsic manner. In addition, ECSIT expression correlated positively with stem-like memory progenitor exhausted CD8 + T cells and the survival of patients with cancer. Our study demonstrates that ECSIT-mediated fumarate synthesis stimulates TCF-1 activity and memory CD8 + T cell development during viral infection and tumorigenesis and highlights the utility of therapeutic fumarate analogues and PD-L1 inhibition for tumour immunotherapy.

Psoriasis is a multifactorial immune-mediated inflammatory disease. Its pathogenesis involves abnormal accumulation of neutrophils and T-cell-related abnormalities. Pyroptosis is a type of regulated cell death associated with innate immunity, but its role in psoriasis is unclear. In this study, we found that gasdermin D (GSDMD ) is higher in human psoriatic skin than that in normal skin, and in imiquimod-induced psoriasis-like mouse skin, the expression of Gsdmd was most significantly altered in neutrophils and Il1b was also mainly expressed in neutrophils. Immunohistochemical staining of serial sections of skin lesions from psoriasis patients and healthy control also showed that GSDMD expression is higher in psoriasis lesion, especially in neutrophils. Gsdmd deficiency mitigates psoriasis-like inflammation in mice. GSDMD in neutrophils contributes to psoriasis-like inflammation, while Gsdmd depletion in neutrophils attenuates the development of skin inflammation in psoriasis and reduces the release of the inflammatory cytokines. We found that neutrophil pyroptosis is involved in and contributes to psoriasis inflammation, which provides new insights into the treatment of psoriasis by targeting neutrophil pyroptosis.

Inflammation in the testes induced by infection and autoimmunity contributes significantly to male infertility, a public health issue. Current therapies using antibiotics and broad-spectrum anti-inflammatory drugs are ineffective against non-bacterial orchitis and induce side effects. This highlights the need to explore the pathogenesis of orchitis and develop alternative therapeutic strategies. In this study, we demonstrated that Gasdermin D (GSDMD) was activated in the testes during uropathogenic Escherichia coli (UPEC)-induced acute orchitis, and that GSDMD in macrophages induced inflammation and affected spermatogenesis during acute and chronic orchitis. In testicular macrophages, GSDMD promoted inflammation and antigen presentation, thereby enhancing the T-cell response after orchitis. Furthermore, the pharmacological inhibition of GSDMD alleviated the symptoms of UPEC-induced acute orchitis. Collectively, these findings provide the first demonstration of GSDMD’s role in driving orchitis and suggest that GSDMD may be a potential therapeutic target for treating orchitis.

The intestinal epithelium is the fastest renewing tissue in mammals and its regenerative process must be tightly controlled to minimize the risk of dysfunction and tumorigenesis. The orderly expression and activation of Yes‐associated protein (YAP) are the key steps in driving intestinal regeneration and crucial for intestinal homeostasis. However, the regulatory mechanisms controlling this process remain largely unknown. Here, it is discovered that evolutionarily conserved signaling intermediate in Toll pathways (ECSIT), a multi‐functional protein, is enriched along the crypt–villus axis. Intestinal cell‐specific ablation of ECSIT results in the dysregulation of intestinal differentiation unexpectedly accompanied with enhanced YAP protein dependent on translation, thus transforming intestinal cells to early proliferative stem “‐like” cells and augmenting intestinal tumorigenesis. Loss of ECSIT leads to metabolic reprogramming in favor of amino acid–based metabolism, which results in demethylation of genes encoding the eukaryotic initiation factor 4F pathway and their increased expression that further promotes YAP translation initiation culminating in intestinal homeostasis imbalance and tumorigenesis. It is also shown that the expression of ECSIT is positively correlated with the survival of patients with colorectal cancer. Together, these results demonstrate the important role of ECSIT in regulating YAP protein translation to control intestinal homeostasis and tumorigenesis.

Abstract The intestinal epithelium is the fastest renewing tissue in mammals and has extensive flexibility to adapt to different types of damage. The orderly expression and activation of the YAP protein is the initial step in driving intestinal development and crucial for intestinal regenerative responses and regulating intestinal homeostasis[1–4]. However, the regulatory mechanisms controlling this process are still unknown. Mitochondria are enriched in the intestinal epithelium and particularly along the crypt-villus axis [5]. But we have little known about the role of mitochondria in maintaining intestinal homeostasis and regulating cell fate determination. In this study, we discovered that mitochondrial complex I assembly was the top enriched mitochondrial gene ontology (GO) along the crypt-villus axis, and ECSIT, the core subunit of Mitochondrial Complex I Intermediate Assembly (MCIA) complex [6, 7], was the top up-regulated mitochondrial factor I factor among this ontology. Intestinal cell-specific ablation of ECSIT results in the dysregulation of intestinal epithelial cell (IEC) differentiation and the development of a spontaneous intestinal inflammation phenotype. Single-cell RNA sequencing also revealed that mice lacking ECSIT in intestinal cells displayed a distinct, early proliferation- type signature in all the major intestinal cells, which we term “-like” cells. The “-like” cells are marked by high YAP protein and downstream YAP transcriptional programs but have no alteration in Yap mRNA level. Mechanistically, we show that the absence of ECSIT in intestinal cells promotes YAP translation initiation through the upregulation of the eIF4F complex. This upregulation is due to the reduced DNA methylation in genes encoding eIF4A1 and eIF4G2. Such DNA methylation reduction is caused by the increased a-ketoglutarate (a-KG): succinate ratio activating Ten-eleven translocation (TET)-dependent DNA demethylation in ECSIT deficient cells. Moreover, decreased ECSIT expression in intestinal cells enhanced susceptibility to tumorigenesis in the context of dysregulated WNT signaling, and the expression of ECSIT is positively correlated with the survival of patients with colorectal cancer. Together, our results reveal a novel and important role of the mitochondrial complex I assembly factor ECSIT and mitochondrial metabolism in maintaining optimal intestinal homeostasis and controlling the development of tumorigenesis by critical regulation of the eIF4F-YAP signalling axis.

Psoriasis, an immune-mediated inflammatory disease, is associated with poor pregnancy outcomes. Emerging evidence indicates that these defects are likely attributed to compromised oocyte competence. Nevertheless, little is known about the underlying associated mechanisms between psoriasis and poor oocyte quality. In this study, we construct an imiquimod-induced chronic psoriasis-like mouse model to review the effects of psoriasis on oocyte quality. We discover that oocytes from psoriasis-like mice display spindle/chromosome disorganization, kinetochore-microtubule mis-attachment, and aneuploidy. Importantly, our results show that melatonin supplement in vitro and in vivo not only increases the rate of matured oocytes but also significantly attenuates oxidative stress and meiotic defects by restoring mitochondrial function in oocytes from psoriasis-like mice. Altogether, our data uncover the adverse effects of psoriasis symptoms on oocytes, and melatonin supplement ameliorates oxidative stress and meiotic defects of oocytes from psoriatic mice.

Inflammatory pathways usually utilize negative feedback regulatory systems to prevent tissue damage arising from excessive inflammatory response. Whether such negative feedback mechanisms exist in inflammasome activation remains unknown. Gasdermin D (GSDMD) is the pyroptosis executioner of downstream inflammasome signaling. Here, we found that GSDMD, after its cleavage by caspase-1/11, utilizes its RFWK motif in the N-terminal β1-β2 loop to inhibit the activation of caspase-1/11 and downstream inflammation in a negative feedback manner. Furthermore, an RFWK motif-based peptide inhibitor can inhibit caspase-1/11 activation and its downstream substrates GSDMD and interleukin-1β cleavage, as well as lipopolysaccharide-induced sepsis in mice. Collectively, these findings provide a demonstration of the N-terminal fragment of GSDMD as a negative feedback regulator controlling inflammasome activation and a detailed delineation of the underlying inhibitory mechanism.

Tumor microenvironments (TMEs) require co-operation of innate and adaptive immune cells, which influence tumor progression and immunotherapy. Caspase-activated gasdermins facilitate tumor death and promote anti-tumor immunity. How pyroptosis in immune cells affects the TME remains unclear. TME expression of gasdermin D (GSDMD) is highly expressed in antigen-presenting cells (APCs) and correlates with immune checkpoint signatures. Through conditional deletion of GSDMD, we demonstrate that GSDMD in TME APCs restricts anti-tumor immunity during PD-L1 inhibition. Loss of GSDMD in APCs enhances interferon-stimulated genes (ISGs), thereby promoting CD8+ T cell activation in a cGAS-dependent manner. Moreover, pharmacological inhibition of GSDMD-mediated pyroptosis and PD-L1 improve anti-tumor immunity, highlighting the potential of combining GSDMD/PD-L1 inhibition for immunotherapy as a therapeutic strategy.

Abstract In mammals, ovarian function is dependent on the primordial follicle pool and the rate of primordial follicle activation determines a female's reproductive lifespan. Ovarian ageing is characterised by chronic low‐grade inflammation with accelerated depletion of primordial follicles and deterioration of oocyte quality. Macrophages (Mφs) play critical roles in multiple aspects of ovarian functions; however, it remains unclear whether Mφs modulate the primordial follicle pool and what is their role in ovarian ageing. Here, by using super‐ or naturally ovulated mouse models, we demonstrated for the first time that ovulation‐induced local inflammation acted as the driver for selective activation of surrounding primordial follicles in each estrous cycle. This finding was related to infiltrating Mφs in ovulatory follicles and the dynamic changes of the two polarised Mφs, M1 and M2 Mφs, during the process. Further studies on newborn ovaries cocultured with different subtypes of Mφs demonstrated the stimulatory effect of M1 Mφs on primordial follicles, whereas M2 Mφs maintained follicles in a dormant state. The underlying mechanism was associated with the differential regulation of the Phosphatidylinositol 3‐kinase/Mechanistic target of rapamycin (PI3K/mTOR) signaling pathway through secreted extracellular vesicles (EVs) and the containing specific miRNAs miR‐107 (M1 Mφs) and miR‐99a‐5p (M2 Mφs). In aged mice, the intravenous injection of M2‐EVs improved ovarian function and ameliorated the inflammatory microenvironment within the ovary. Thus, based on the anti‐ageing effects of M2 Mφs in old mice, M2‐EVs may represent a new approach to improve inflammation‐related infertility in women.

The decrease of neurotransmitter dopamine (DA) levels in the intestine is closely related to the development of inflammatory bowel disease (IBD). However, the functional relevance and underlying mechanistic basis of the effects of DA signaling on IBD remains unclear. Here, we observed that the DRD5 receptor is highly expressed in colonic macrophages, and the deficiency of DA-DRD5 signaling exacerbated experimental colitis. Moreover, DA-DRD5 signaling can inhibit M1 by negatively regulating NF-κB signaling but promote M2 macrophage polarization through activation of the CREB pathway, respectively. The deficiency of DRD5 signaling increased colonic M1 macrophages but reduced M2 cells during colitis. Additionally, the administration of a D1-like agonist that has a higher affinity to DRD5 can attenuate the colitogenic phenotype of mice. Collectively, these findings provide the first demonstration of DA-DRD5 signaling in colonic macrophages controlling the development of colitis by regulating M1/M2 macrophage polarization.