Spexin modulates molecular thermogenic profile of adipose tissue and thermoregulatory behaviors in female C57BL/6 mice

Thermoregulation is the physiological process by which an animal regulates body temperature in response to its environment. It is known that galanin, a neuropeptide widely distributed throughout the central nervous system and secreted by the gut, plays a role in thermoregulatory behaviors and metabolism. We tested the ability of the novel neuropeptide spexin, which shares sequence homology to galanin, to regulate these functions in female mice. Supraphysiological levels of spexin in C57BL/6 mice did not lead to weight loss after 50 days of treatment. Behavioral analysis of long-term spexin treatment showed it decreased anxiety and increased thermoregulatory nest building, which was not observed when mice were housed at thermoneutral temperatures. Treatment also disrupted the thermogenic profile of brown and white adipose tissue, decreasing mRNA expression of Ucp1 in BAT and immunodetection of β3-adrenergic receptors in gWAT. Our results reveal novel functions for spexin as a modulator of thermoregulatory behaviors and adipose tissue metabolism.

Antigen-Multimers: Specific, Sensitive, Precise, and Multifunctional High-Avidity CAR-Staining Reagents

Although chimeric antigen receptor (CAR) T-cell therapy has transformed cancer treatment, high-quality and universal CAR-staining reagents are urgently required to manufacture CAR T cells, predict therapy response, decipher CAR biology, and engineer new CARs. Here, we developed tetrameric and dodecameric forms of a multifunctional and extensible category of high-avidity CAR-staining reagents: antigen-multimers. Antigen-multimers detected CARs against CD19, HER2, and Tn-glycoside with significantly higher specificity, sensitivity, and precision than existing reagents. In addition to accurate CAR T-cell detection by flow cytometry, antigen-multimers also enabled ≥100-fold magnetic enrichment of rare CAR T cells, selective CAR T-cell stimulation, and high-dimensional CAR T-cell profiling by single-cell multi-omics analyses. Finally, antigen-multimers accurately captured clinical anti-CD19 CAR T cells from patients' cellular infusion products, post-infusion peripheral blood, and tumor biopsies. Antigen-multimers can be readily extended to other CAR systems by switching its antigen ligand. As such, antigen-multimers have broad clinical and research applications.

SUN-102 Spexin Differentially Regulates Adipogenesis in Brown and White Adipose Tissue Depots

In the last decade, neuropeptide Q or spexin (SPX) was implicated in central and peripheral functions including feeding suppression and lipid metabolism. To test whether spexin acts on brown and white adipose tissue, we performed subcutaneous micro-osmotic infusion of spexin in mice with diet-induced obesity. Our preliminary results indicate that spexin may differentially regulate biomarkers of adipogenesis and insulin sensitivity in brown and white adipose tissue. Spexin infusion increased interscapular brown adipose tissue mass and mRNA expression of adiponectin, fatty-acid binding protein 4, lipoprotein lipase, and C/EBP-⍺ in female C57BL/6 mice. Within gonadal white adipose tissue, spexin and PPAR-γ2 mRNA expression was upregulated while immunohistochemistry of gWAT revealed that β3-adrenergic receptor expression was significantly decreased while adipocyte diameter was increased. These results indicate that spexin infusion differentially regulates adipogenesis within brown adipose tissue by increasing BAT mass and increasing non-adrenergic regulation of adipogenesis within gonadal white adipose tissue.