Semaphorin 4B is an ADAM17-cleaved adipokine that inhibits adipocyte differentiation and thermogenesis

Multi-Omics Analysis Identifies Genetic Mechanisms and Therapeutic Targets for Acne Vulgaris

Acne vulgaris is a chronic inflammatory disorder with complex pathophysiology. However, challenges such as antibiotic resistance, side effects, and recurrence highlight the need for precision therapies. This study employed a multi-omics approach, integrating summary-data-based Mendelian randomization (SMR), colocalization, two-sample MR (TSMR), transcriptome-wide (TWAS) and proteome-wide (PWAS) association studies, and functional analyses to identify acne-associated genes and proteins. We analyzed acne GWAS data (n_cases = 34,422; n_controls = 364,991), eQTL datasets from blood, skin-related tissues, and fibroblasts, along with six pQTL databases and a blood mQTL dataset. SMR and sensitivity analyses identified 16 candidate genes, refined to 9 by TWAS. Protein-level SMR and PWAS further recognized two plasma proteins (CRELD2 and TIMP4), with CRELD2 also supported by gene-level associations. A total of 10 non-redundant targets were functionally analyzed, revealing pathways beyond molecular transport, such as carnitine metabolism. Moreover, methylation regulated key genes, and immune cell-specific loci overlapped with acne risk. Transcriptomic data confirmed differential expression of several targets in acne lesions. Finally, we prioritized acne drug targets based on our results and their druggability, highlighting SLC22A5 activators and CRELD2 inhibitors as promising tier 1 candidates. These findings advance the molecular understanding of acne pathogenesis and suggest potential therapeutic targets.

MAFB in macrophages regulates cold-induced neuronal density in brown adipose tissue

Transcription factor MAFB regulates various homeostatic functions of macrophages. This study explores the role of MAFB in brown adipose tissue (BAT) thermogenesis using macrophage-specific Mafb-deficient (Mafbf/f::LysM-Cre) mice. We find that Mafb deficiency in macrophages reduces thermogenesis, energy expenditure, and sympathetic neuron (SN) density in BAT under cold conditions. This phenotype features a proinflammatory environment that is characterized by macrophage/granulocyte accumulation, increases in interleukin-6 (IL-6) production, and IL-6 trans-signaling, which lead to decreases in nerve growth factor (NGF) expression and reduction in SN density in BAT. We confirm MAFB regulation of IL-6 expression using luciferase readout driven by IL-6 promoter in RAW-264.7 macrophage cell lines. Immunohistochemistry shows clustered organization of NGF-producing cells in BAT, which are primarily TRPV1+ vascular smooth muscle cells, as additionally shown using single-cell RNA sequencing and RT-qPCR of the stromal vascular fraction. Treating Mafbf/f::LysM-Cre mice with anti-IL-6 receptor antibody rescues SN density, body temperature, and energy expenditure.

Pathophysiological functions of semaphorins in the sympathetic nervous system

Upon exposure to external stressors, the body senses them and activates the sympathetic nervous system (SNS) to maintain the homeostasis, which is known as the "fight-or-flight" response. Recent studies have revealed that the SNS also plays pivotal roles in regulating immune responses, such as hematopoiesis, leukocyte mobilization, and inflammation. Indeed, overactivation of the SNS causes many inflammatory diseases, including cardiovascular diseases, metabolic disorders, and autoimmune diseases. However, the molecular basis essential for SNS-mediated immune regulation is not completely understood. In this review, we focus on axon guidance cues, semaphorins, which play multifaceted roles in neural and immune systems. We summarize the functions of semaphorins in the crosstalk between the SNS and the immune system, exploring its pathophysiological roles.