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Adrenocortical carcinomas (ACC) are aggressive and resistant to medical treatment. This study reports a single-nucleus transcriptome atlas of steroid and microenvironment cells in 38 human normal adrenals and adrenocortical tumors. We identify intermediate-state cells between glomerulosa and fasciculata, a transition state in the centripetal trans-differentiation of normal steroid cells. In tumors, steroid cells show expression programs reflecting this zonation. Although ACC microenvironment is scarce, its signatures combine with those of steroid cells into ecotypes. A first ecotype combines cancer-associated fibroblasts, tumor-associated endothelial cells, with hypoxia and mitosis signatures in steroid cells. Another ecotype combines exhausted T cells, with fasciculata steroid signature. These ecotypes are associated with poor survival. Conversely, a third ecotype combines inflammatory macrophages, with reticularis steroid signature, and better outcome. These steroid/microenvironment cells interplays improve outcome predictions and may open therapeutic options in aggressive ACC, through immune microenvironment activation by modulating glucocorticoids/androgens balance. Adrenocortical carcinomas (ACC) are aggressive and often resistant to therapy. Here, the authors provide a single-nucleus transcriptomic atlas of ACCs and normal adrenal glands, finding ecotypes in steroid and microenvironment cells that are associated with clinical outcomes.

As an important immune stimulator and modulator, IFNγ is crucial for gut homeostasis and its dysregulation links to diverse colon pathologies, such as colitis and colorectal cancer (CRC). Here, we demonstrated that the epigenetic regulator, CBX3 (also known as HP1γ) antagonizes IFNγ signaling in the colon epithelium by transcriptionally repressing two critical IFNγ-responsive genes: STAT1 and CD274 (encoding Programmed death-ligand 1, PD-L1). Accordingly, CBX3 deletion resulted in chronic mouse colon inflammation, accompanied by upregulated STAT1 and CD274 expressions. Chromatin immunoprecipitation indicated that CBX3 tethers to STAT1 and CD274 promoters to inhibit their expression. Reversely, IFNγ significantly reduces CBX3 binding to these promoters and primes gene expression. This antagonist effect between CBX3 and IFNγ on STAT1/PD-L1 expression was also observed in CRC. Strikingly, CBX3 deletion heightened CRC cells sensitivity to IFNγ, which ultimately enhanced their chemosensitivity under IFNγ stimulation in vitro with CRC cells and in vivo with a syngeneic mouse tumor model. Overall, this work reveals that by negatively tuning IFNγ-stimulated immune genes’ transcription, CBX3 participates in modulating colon inflammatory response and CRC chemo-resistance. Synopsis The epigenetic regulator CBX3 (also known as HP1γ) antagonized IFNγ/STAT1/PD-L1 axis and thereby decreased IFNγ-stimulated immune genes transcription, which ultimately modulated colon inflammatory response and CRC chemo-resistance. CBX3 deletion resulted in chronic mouse colon inflammation, accompanied by upregulated STAT1 and PD-L1 levels in the colon epithelium. CBX3 deletion heightened CRC cells’ sensitivity to IFNγ stimulation and increased STAT1/PD-L1 expression. CBX3 antagonized IFNγ signaling by tethering to the promotors of Stat1 and Cd274, and transcriptionally repressing their expression. IFNγ stimulation reduced CBX3 binding and primed gene expression. Re-sensitizing CRC cells to IFNγ by deletion CBX3 enhanced their chemosensitivity under IFNγ stimulation in vitro as well as in vivo. The epigenetic regulator CBX3 (also known as HP1γ) antagonized IFNγ/STAT1/PD-L1 axis and thereby decreased IFNγ-stimulated immune genes transcription, which ultimately modulated colon inflammatory response and CRC chemo-resistance.

Ehlers-Danlos syndromes (EDS) comprise a genetically and clinically heterogenous group of rare diseases that cause severe, often fatal, damage to connective tissue. The molecular basis of EDS implicates defects in extracellular matrix components, including various fibrillar collagens and glycosaminoglycans (GAGs). However, the precise pathogenic mechanisms behind EDS remain elusive. Here, we have implemented a multi-tiered approach to demonstrate the functional impact of B3GALT6 mutations on biochemical and developmental processes, ultimately leading to the spondylodysplastic subtype of EDS (spEDS), characterized by severe musculoskeletal symptoms. We show that the loss of function of β1,3-galactosyltransferase 6 (β3GalT6) is partially compensated by β1,3-glucuronosyltransferase 3 (GlcAT-I), the next enzyme in the GAG biosynthetic pathway. In addition, results from transcriptomics, collagen analysis, and biophysical experiments revealed that impaired collagen maturation, including defective glycosylation of collagen XII, contributes to altered tissue structure and biomechanics, the hallmarks of spEDS. Our findings unravel a new pathogenic mechanism of spEDS and bring us one step closer to therapeutic strategies, including cell and tissue engineering.

Abstract Disclosure: P. Houeiss: None. S. luce: None. C. Boitard: None. Anti-PD1 is an immune checkpoint inhibitor that has revolutionized cancer treatment. It blocks the interaction between PD1, a receptor on the surface of activated or exhausted T cells, and its ligands PDL1 and PDL2, to inhibit the immune response. However, anti-PD1 induces T1D in 0.4-2% of patients raising questions about the risk factors and the mechanisms behind T1D development. Since the pancreas of these patients is inaccessible, we focus on autoimmune diabetes induction in a transgenic mouse model modified to express the T1D susceptibility genes HLA-DQ8, HLA-A2.1 and the human preproinsulin and on identifying new targets to prevent or treat this disease. Thus, 8 to 12 weeks old mice were treated initially with 500 micrograms of anti-PD1 followed by 250 micrograms every other day for 10 days. Control mice received 6 injections of PBS. Mice were followed up for evidence of hyperglycemia for 60 days. Cells and tissues from the pancreas, and the spleens were isolated 15-, 30- or 60-days post-treatment initiation and analyzed by flow cytometry and immunohistochemistry. Although diabetes incidence in treated mice was 14% (n=14), insulitis incidence progressively increased over time reaching 86% on D60 (p=0.005). On Day 15, in the spleen, a significant 10% increase of CD4+Foxp3+CD25- T cells at the expense of the CD4+Foxp3- T cells were seen in the treatment group as compared to the control (37.1±4.25 vs 26±3.5, p<0.01, n=5 per group). In the treatment group, PD1 expression significantly increased on CD4+Foxp3+ T cells whereas PDL1 expression increased on CD4+Foxp3- and CD8+ T cells (p<0.01). On D30, in the pancreas, infiltrates show positive staining for F4/80+, CD4+ and CD8+ T cells with scarce foxp3+ T cells. While the absolute percentage of CD4+Foxp3+ T cells increased in the insulitis and diabetes group, their percentage among CD3+ T cells decreased in the insulitis (10.2%) and diabetes group (3.9%) as compared to the control group (13.5%). Infiltrates were concentrated around the islets and the efferent and afferent vessels, and extended to the exocrine pancreas, leading to secondary acinar destruction. In the pancreatic infiltrates from anti-PD1 treated mice, we noted a significant increase in CD4+ T cells recognizing Ins13-21 monomers as compared to the negative control. PD1 blockade induced an insulitis characterized by a Treg to effector T cells imbalance. Thus, it acted on the early phase of T1D. In conclusion, this model describes a new T1D endotype that shares similarities with ICI induced diabetes in patients. Presentation: 6/2/2024