CD11c regulates late-stage T cell development in the thymus

Exploring the Relationship Between Immune Cells and Chronic Kidney Disease by Mendelian Randomization, Colocalization Analysis, and SMR

Background: Chronic kidney disease (CKD) impacts millions of individuals annually. Current research suggests that immune factors played a significant role in CKD. However, the potential causal relationship between them remains unclear. Methods: We conducted a comprehensive Mendelian randomization (MR) analysis to assess the potential causal association between 731 immune cells and CKD. Sensitivity analysis was performed to test for heterogeneity and horizontal pleiotropy, including the Cochran Q test, leave-one-out test, MR-Egger intercept analysis, and MR-PRESSO test. The bidirectional MR was utilized to investigate the bidirectional relationship between the immune cells and CKD. Multivariable MR was also conducted to mitigate confounding among immune cells. The colocalization analysis was performed to find the key genes of immune cells. We used the Summary data-based MR (SMR) analysis to generate effect estimates between the cis-eQTL and immune cells. The heterogeneity in dependent instruments (HEIDIs) test was used to test the heterogeneity between dependent instrumental variables. Results: We identified 14 potential pathogenic factors and six potential protective factors through the univariable MR. Moreover, we did not find reverse causation by using the bidirectional MR. We finally identified one risk factor and two protective factors after multivariate MR adjustment for effects between immune cells. CD28 on CD28+ CD45RA+ CD8+ T cell could increase the risk of CKD (Pval: 0.033, OR: 1.112, 95% CI: 1.009-1.227). CD11c on myeloid dendritic cell (DC) could decrease the risk of CKD (Pval: 0.02, OR: 0.854, 95% CI: 0.748-0.975). CD45RA on naive CD4+ T cell could decrease the risk of CKD (Pval: 0.026, OR: 0.918, 95% CI: 0.852-0.990). Importantly, we observed no evidence of heterogeneity and pleiotropy, signifying the robustness of our results. BACH2 (PPH4.abf = 0.999, P_SMR: <0.001, P_HIEDI: 0.132) and HLA-G (PPH4.abf = 0.990, P_SMR: <0.001, P_HIEDI: 0.141) shared the same variant with CD28 on CD28+ CD45RA+ CD8+ T cell. PAQR9 (PPH4.abf = 0.992, P_SMR: <0.001, P_HIEDI: 0.215) shared the same variant with CD11c on myeloid DC. Conclusion: MR identified a potential correlation between CKD and immune cells. Colocalization and SMR found the key genes of immune cells. Our findings offer insights into the prevention and management of CKD. However, further investigation is required to elucidate the precise mechanisms underlying this relationship.

Multifaceted, unique role of CD11c in leukocyte biology

CD11c is widely known as a dendritic cell surface marker but its non-dendritic cell expression profiles as well as its functional role have been gradually delineated. As a member of leukocyte-specific β2 integrin family, CD11c forms a heterodimer with CD18. CD11c/CD18 takes different conformations, which dictate its ligand binding. Here we reviewed CD11c current state of art, in comparison to its sister proteins CD11a, CD11b, and CD11d, illustrating its unique feature in leukocyte biology.

Exploring Localized Provoked Vulvodynia: Insights from Animal Model Research

Provoked vulvodynia represents a challenging chronic pain condition, characterized by its multifactorial origins. The inherent complexities of human-based studies have necessitated the use of animal models to enrich our understanding of vulvodynia's pathophysiology. This review aims to provide an exhaustive examination of the various animal models employed in this research domain. A comprehensive search was conducted on PubMed, utilizing keywords such as "vulvodynia", "chronic vulvar pain", "vulvodynia induction", and "animal models of vulvodynia" to identify pertinent studies. The search yielded three primary animal models for vulvodynia: inflammation-induced, allergy-induced, and hormone-induced. Additionally, six agents capable of triggering the condition through diverse pathways were identified, including factors contributing to hyperinnervation, mast cell proliferation, involvement of other immune cells, inflammatory cytokines, and neurotransmitters. This review systematically outlines the various animal models developed to study the pathogenesis of provoked vulvodynia. Understanding these models is crucial for the exploration of preventative measures, the development of novel treatments, and the overall advancement of research within the field.

Integrin CD11c regulates B cell homeostasis

CD11c is widely known as a cell surface marker for dendritic cells, but we recently showed that it regulates neutrophil and T cell functions. Because we found that CD11c knockout (KO) mice had lower blood B cell counts, we characterized B cell profile in developmental stages. We found that CD11c KO recirculating and mature B cells was significantly fewer compared with wild type, associated with exaggerated proliferation and apoptosis. Because they did not express CD11c, we sought for the possibility of CD11c-mediated non-intrinsic regulation of B cell proliferation and apoptosis. Here we hypothesized that dendritic cells, major cells expressing CD11c would regulate B cells indirectly. The proteomics of dendritic cells cultured in vitro indicated the downregulation of macrophage migration inhibitory factor (MIF). Less MIF was also confirmed by ELISA. Furthermore, plasma MIF level was significantly lower in naïve CD11c KO mice. Because MIF regulates B cell survival, we demonstrated a novel regulatory mechanism of naïve B cells via CD11c.

CD11a regulates hematopoietic stem and progenitor cells

Integrin αLβ2 (CD11a/CD18, CD11a) is a critical leukocyte adhesion molecule in leukocyte arrest and immunological synapse formation. However, its role in the bone marrow has not been investigated in depth. Here we showed that CD11a was expressed on all subsets of hematopoietic stem and progenitor cells (HPSCs). CD11a deficiency enhanced HSPCs activity under lipopolysaccharide (LPS) stimulation as demonstrated by a higher HSPC cell count along with an increase in cell proliferation. However, our mixed chimera experiment did not support that this phenotype was driven in a cell-intrinsic manner. Rather we found that the production of IL-27, a major cytokine that drives HSPC proliferation, was significantly upregulated both in vivo and in vitro. This adds a novel role of CD11a biology.