Cold stress induces adaptive remodeling of adipose tissue, yet the coordinated molecular network, particularly the interplay between upstream signaling pathways and downstream cellular responses, remains incompletely understood. This study investigated whether cold stress regulates adipose tissue beiging, apoptosis, and systemic metabolic remodeling through autophagy and inflammation mediated by the β3-adrenergic receptor (ADRB3)-extracellular signal-regulated kinase (ERK) signaling axis. The results demonstrated that cold stress significantly increased energy expenditure and markedly improved glucose tolerance and insulin sensitivity in Min pigs. In subcutaneous adipose tissue, cold stress induced pronounced beiging, as evidenced by reduced adipocyte size, the presence of multilocular lipid droplets, and upregulation of beige adipocyte marker genes, accompanied by increased preadipocyte apoptosis. Transcriptomic analysis revealed significant enrichment of pathways related to autophagy and lipolysis, with inflammation (notably the TNF signaling pathway) also identified as a potential contributing process. Mechanistically, cold stress activated the ADRB3-ERK signaling axis, leading to enhanced autophagic activity, and inflammation-related genes were also upregulated, suggesting that inflammation may serve as a candidate process cooperating with autophagy. In conclusion, this study reveals a novel molecular mechanism whereby cold stress activates the ADRB3-ERK signaling axis to stimulate autophagy, with inflammation potentially cooperating as a candidate process, thereby driving adipose tissue beiging, apoptosis, and systemic metabolic remodeling.

Meat quality in pigs is fundamentally shaped by the relative abundance and metabolic properties of distinct skeletal muscle fiber types. Dihydrolipoyl dehydrogenase (DLDH), an indispensable catalytic subunit of mitochondrial dehydrogenase complexes, has been documented to link with myocyte development; nevertheless, the effects of the causal regulatory variants governing transcription of its encoding gene DLD on the myogenic fate remain largely uncharacterized. In this study, comparative polymorphism analysis between Large White and Min pigs uncovered a regulatory single nucleotide polymorphism (SNP) at position −143 A>C within the porcine DLD promoter. Mechanistic dissection using dual-luciferase reporter, electrophoretic mobility shift, and chromatin immunoprecipitation assays revealed that the C allele strengthens Krüppel-like factor 2 (KLF2) DNA-binding affinity and potentiates KLF2-mediated transcriptional repression, leading to significantly reduced DLD expression. Functional characterization in porcine primary myoblasts demonstrated that DLD promotes myoblast proliferation by accelerating G2/M transition and upregulating cell-cycle regulators while suppressing terminal differentiation. Furthermore, DLD overexpression inhibited slow-twitch (myosin heavy chain (MYH) 7-positive) myogenic differentiation and suppressed the expression of myogenic regulatory factors MYOD and MYOG, whereas DLD knockdown produced converse effects. Taken together, these multiple lines of evidence suggest that the −143 A>C variant may reinforce transcriptional repression of DLD by increasing KLF2-binding occupancy. Because reduced DLD expression favors MYH7-positive myotube formation in our myoblast assays, this variant is hypothesized to influence myotube subtype balance. These findings may provide a potential molecular mechanism contributing to pork-quality variation and suggest the −143 A>C variant on the DLD promoter as a candidate marker for future genomic-selection studies.

Pathogenic infections caused by intestinal microecological imbalance pose a critical threat to livestock breeding and human health. Multiple probiotic functions of Lacticaseibacillus casei (L. casei), an important probiotic, are modulated by pyrR-mediated pyrimidine metabolism. This study used L. casei isolated from the intestines of Min pigs (a local pig breed from northeastern China) and its pyrR gene knockout mutant (named L. casei ΔpyrR, ΔpyrR) to investigate their antibacterial, anti-inflammatory, and antioxidant capacities. The results showed that the mutant exhibited significantly attenuated effects compared with the wild-type in disrupting pre-formed biofilms, damaging bacterial morphology, and downregulating the expression of related genes (biofilm and flagellar genes) in Staphylococcus aureus (S. aureus) and Salmonella typhimurium (S. typhimurium). The mutant-derived supernatant also exhibited impaired anti-inflammatory effects in S. typhimurium-challenged IPEC-J2 cells: it was less effective at restraining pathogen-induced IL-1β upregulation and boosting the production of host-derived TGF-β and IL-10, accompanied by altered regulation of the host STING signaling pathway. However, existing data cannot fully distinguish whether STING alteration corresponds to suppressed inflammation or impaired immunity. Additionally, pyrimidine metabolism in L. casei suppresses pathogen-induced reactive oxygen species (ROS) accumulation. These findings are consistent with pyrR-mediated pyrimidine synthesis contributing to the probiotic functions of L. casei, providing an experimental basis for optimizing probiotic preparations and substituting antibiotics.

Cold exposure is a major physiological stimulus that promotes adipose tissue browning and enhances thermogenic capacity. As a cold-tolerant breed, Min pigs may rely on distinct adaptive mechanisms in adipose tissues, but how different adipose depots respond to cold stress remains unclear. This study systematically examines how cold exposure affects adipose tissue morphology, thermogenic gene expression, and the differentiation potential of preadipocytes derived from four adipose depots—cervical, axillary, perirenal, and inguinal—in Min pigs. Adipose tissues from the four depots were collected and analyzed using infrared thermography, histological staining, scanning electron microscopy, real-time quantitative PCR, Western blotting and in vitro differentiation assays. The results demonstrated that cold stress induced depot-specific remodeling patterns. Infrared thermography showed that the subcutaneous adipose depots including inguinal and axillary depots maintained relatively higher surface temperatures following cold exposure. Histological and ultrastructural analyses revealed typical beige-like characteristics in inguinal depots, including the accumulation of small lipid droplets, whereas changes in other depots were minimal. Molecular analyses further confirmed this heterogeneity: inguinal depots exhibited the strongest beiging response, characterized by significant upregulation of key thermogenic markers (PGC1α, UCP3, and DIO2) and lipolytic genes (HSL and ATGL) at the mRNA and/or protein levels. In contrast, visceral adipose depots showed weak or suppressed thermogenic activation. In vitro differentiation assays demonstrated that preadipocytes isolated from inguinal depot had the strongest beiging potential, forming tightly packed small lipid droplets and markedly increasing the expression of beige adipose-related genes upon induction. In conclusion, this study demonstrates that cold stress induces distinct beige remodeling across adipose depots in Min pigs, with the inguinal depot exhibiting the strongest thermogenic response and differentiation potential at morphological, molecular, and cellular levels. These findings identify the inguinal depot as a key site for adaptive thermogenesis and provide novel insights into adipose tissue remodeling and environmental adaptation in large mammals.