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Complex bidirectional cross talk between adipocytes and adipose tissue immune cells plays an important role in regulating adipose function, inflammation, and insulin responsiveness. Adipocytes secrete the pleiotropic cytokine IL-6 in response to both inflammatory and catabolic stimuli. Previous studies have suggested that IL-6 secretion from adipocytes in obesity may promote adipose tissue inflammation. Here, we investigated catabolic stimulation of adipocyte IL-6 secretion and its impact on adipose tissue immune cells. In obesity, catecholamine resistance reduces cAMP-driven adipocyte IL-6 secretion in response to catabolic signals. By restoring adipocyte catecholamine sensitivity in obese adipocytes, amlexanox stimulates adipocyte-specific IL-6 secretion. We report that in this context, adipocyte-secreted IL-6 activates local macrophage STAT3 to promote Il4ra expression, thereby sensitizing them to IL-4 signaling and promoting an anti-inflammatory gene expression pattern. Supporting a paracrine adipocyte to macrophage mechanism, these effects could be recapitulated using adipocyte conditioned media to pretreat bone marrow-derived macrophages prior to polarization with IL-4. The effects of IL-6 signaling in adipose tissue are complex and context specific. These results suggest that cAMP-driven IL-6 secretion from adipocytes sensitizes adipose tissue macrophages to IL-4 signaling.

Renal arginine vasopressin receptor 2 (AVPR2) plays a crucial role in osmoregulation. Engagement of ligand with AVPR2 results in aquaporin 2 movement to the apical membrane and water reabsorption from the urinary filtrate. Despite this essential role, little is known about transcriptional regulation of Avpr2. Here, we identify novel roles for PAX2, a transcription factor crucial for kidney development, and its adaptor protein, Pax transcription interacting protein (PTIP), for epigenetic regulation of Avpr2 and thus body water balance. Chromatin immunoprecipitation (ChIP) from murine inner medulla cells (IMCD-3) identified the minimal DNA-binding region of PAX2 on the Avpr2 promoter. Regulation of Avpr2 by PAX2 was confirmed using a heterologous DNA expression system. PAX2 recruits the adaptor protein PTIP and its associated histone methyltransferase (HMT) complex to Avpr2 promoter, imposing epigenetic marks on this region and throughout the coding sequence that modulate Avpr2 gene transcription. Reduction of PAX2 or PTIP protein levels by siRNA prevented histone lysine methylation and expression of Avpr2. ChIP using mouse or human kidneys determined that PAX2 is highly enriched in the AVPR2 promoter alongside PTIP and HMT proteins, leading to high levels of histone H3 lysine trimethylation within the promoter and throughout the gene. In conclusion, PAX2 provides locus specificity for PTIP, allowing the HMT complex to impart epigenetic changes at the Avpr2 locus and regulate Avpr2 transcription. These finding have major implications for understanding regulation of body water balance. NEW & NOTEWORTHY The transcription factor PAX2 plays an indispensable role in kidney development. In the adult kidney, we identified the first described protein this protein regulates. PAX2 and its interacting partner Pax transcription interacting protein recruit a histone methyltransferase complex to the promoter and epigentically regulate the expression of arginine vasopressin receptor 2, a protein that plays a crucial role in osmoregulation in the distal tubule. [ABSTRACT FROM AUTHOR]

Obesity causes dramatic proinflammatory changes in the adipose tissue immune environment, but relatively little is known regarding how this inflammation responds to weight loss (WL). To understand the mechanisms by which meta-inflammation resolves during WL, we examined adipose tissue leukocytes in mice after withdrawal of a high-fat diet. After 8 weeks of WL, mice achieved similar weights and glucose tolerance values as age-matched lean controls but showed abnormal insulin tolerance. Despite fat mass normalization, total and CD11c+ adipose tissue macrophage (ATM) content remained elevated in WL mice for up to 6 months and was associated with persistent fibrosis in adipose tissue. ATMs in formerly obese mice demonstrated a proinflammatory profile, including elevated expression of interferon-γ, tumor necrosis factor-α, and interleukin-1β. T-cell-deficient Rag1-/- mice showed a degree of ATM persistence similar to that in WT mice, but with reduced inflammatory gene expression. ATM proliferation was identified as the predominant mechanism by which ATMs are retained in adipose tissue with WL. Our study suggests that WL does not completely resolve obesity-induced ATM activation, which may contribute to the persistent adipose tissue damage and reduced insulin sensitivity observed in formerly obese mice. [ABSTRACT FROM AUTHOR]

Patients treated with chimeric antigen receptor T-cell (CAR-T) therapy are subject to profound immune suppression. Dynamics of immune reconstitution (IR) and impacts of IR on outcomes following infusion across CAR-T products are not well understood. Here, we profiled IR in 263 patients with relapsed/refractory large B-cell lymphoma receiving CAR-T therapy (axicabtagene ciloleucel 44.9%, lisocabtagene maraleucel 30.4%, tisagenlecleucel 24.7%). Following infusion, patients remain persistently immunosuppressed, with 48.1% having CD4+ T cell counts <200/µL and median CD3-19+ B cell counts remaining zero through 1 year after CAR-T. IR differences exist by product, with fastest CD4+ T cell recovery seen for tisagenlecleucel, driven primarily by more rapid recovery of the CD4+CCR7-45RA- effector memory subset. Natural killer cell, but not CD4+ T cell, recovery is significantly associated with favorable progression-free (HR: 0.647; 95% CI: 0.476-0.880) and overall survival (HR: 0.637; 95% CI: 0.441-0.920) and inversely correlated with inflammatory markers measured at time of infusion.

Background: Stellate ganglion blockade has been demonstrated as an efficacious treatment for refractory ventricular tachyarrhythmias. There are no published reports of the use of this technique in management of rapid atrial arrhythmia., Case Summary: A 73-year-old woman presented to our institution in rapid atrial fibrillation and cardiogenic shock. She was intubated for airway protection and underwent successful electrical cardioversion. However, atrial fibrillation returned multiple times with weaning of sedation for extubation. Stellate ganglion infusion catheter was placed with infusion of ropivacaine and subsequent maintenance of sinus rhythm, with successful extubation, ablation of atrial fibrillation, improvement of left ventricular ejection fraction, and discharge., Take-Home Message: For selected patients, stellate ganglion blockade can be used as a technique to aid in the management of rapid atrial fibrillation., Competing Interests: Dr Cheung has been a consultant for Abbott, Biosense Webster, Biotronik, Boston Scientific, and Medtronic; and has provided research support to Boston Scientific. Dr Markowitz has done consulting for Boston Scientific, Abbott Laboratories, and Zoll Medical. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2024 Published by Elsevier on behalf of the American College of Cardiology Foundation.)