Niu et al report a diabetes-induced ISG15+ Müller glial subtype, triggered by microglial immune signaling, that weakens antioxidant defenses and contributes to early retinal vascular damage in murine diabetic retinopathy. The cover image shows murine retinal vasculature isolated using trypsin digestion followed by PAS staining, with acellular capillaries visible.
The establishment of mixed hematopoietic chimerism is a promising way to induce immune tolerance for islet replacement therapy and to treat the underlying autoimmunity in type 1 diabetes (T1D). Mixed chimerism not only promotes effective thymic negative selection of autoreactive cells but also restores regulatory T cell (Treg) function and peripheral tolerance. In the current study, we determined that a novel class of donor-derived CD8+CD44+CD122+ Tregs (d-CD8+CD122+ Tregs) plays a crucial role in controlling autoimmunity in non-obese diabetic (NOD) mice with induced mixed chimerism. Using adoptive T cell transfer experiments, we showed that d-CD8+CD122+ Tregs abrogate autoimmunity by suppressing the exogenously injected diabetogenic T cells in Recombination-Activating Gene deficient NOD mice. These d-CD8+CD122+ Tregs from NOD chimeras show upregulation of Helios, Programmed cell death protein 1, perforin, granzyme-B, CD39, Folate receptor 4, and downregulation of proinflammatory marker SCART1. Using in vitro assays, we show that d-CD8+CD122+ Tregs respond specifically to a Complementarity-Determining Region-3 peptide sequence derived from T cell receptors of islet antigen-specific autoreactive T cells. Similarly, we found that individuals with T1D have a deficiency in CD8+CD122+ Tregs, suggesting a potential loss of regulatory function accompanies disease onset. Revitalizing CD8+CD122+ Tregs may offer a new therapeutic strategy of restoring immune tolerance in autoimmune diabetes.
Shiva Pathak, Cameron S. Bader, Bettina P. Iliopoulou, Shobha Regmi, Pin-I Chen, Biki Gupta, Xiangni Wu, Blake Mosher, Alexandra Wells, Levon Witherspoon, Kayla C. Jenkins, William Harper, Emily Y. SooHoo, Abigail Twoy, Rizwan Ahmed, Suparna Dutt, Nadine Nagy, Kent P. Jensen, C. Garrison Fathman, Avnesh S. Thakor, Mark M. Davis, Everett H. Meyer
BACKGROUND. Dementia is a rapidly expanding public health problem with major socio-economic burden. Insulin resistance (IR) is a prevalent but modifiable risk factor for dementia, yet its effects on brain structure, functional connectivity, and metabolism remain incompletely understood. METHODS. Regional brain glucose uptake (PET), volumes (MRI), functional connectivity (fMRI), and cognition (NIH Toolbox) was measured in 72 adults with or without markers of IR. To evaluate reversibility of IR-associated brain deficits, forty older adults with IR were randomized to forty weeks of metformin or placebo, and brain measures were repeated. As a proof-of-concept experiment, we developed a conditional brain-specific insulin receptor knockout mouse and assessed brain mitochondrial function and cognition. RESULTS. In older adults with markers of IR is associated with diminished total and regional brain volumes in areas critical for neuronal connectivity, memory, and learning, including cerebral white matter and the hippocampus. Reduced functional connectivity between brain regions detrimental for cognition was also noted. Further, we demonstrated that ATP production, essential for neuronal connectivity, was diminished in neuron-specific insulin receptor knockout mice accompanied by deficits in hippocampal- and prefrontal-dependent tasks. Forty weeks of metformin improved systemic insulin sensitivity concurrent to preserved brain glucose uptake, volume, and functional connectivity within specific regions central to decision-making and learning. Metformin was also associated with an improved composite measure of processing speed and working memory. CONCLUSION. These findings highlight IR as a key regulator of brain metabolism and support the concept that insulin sensitization can prevent neurobiological deficits in older people with IR.
Mark W. Pataky, Gregory N. Ruegsegger, Hang Joon Jo, Katherine A. Klaus, Kyle J. Sevits, Robert G. Leija, Arathi Prabha Kumar, Seokbeen Lim, Sumaiya Sinhawansa, Rickey E Carter, Nikki H. Stricker, Val J. Lowe, John D. Port, K. Sreekumaran Nair
BACKGROUND. Primary adrenal insufficiency (PAI) is commonly caused by autoimmunity in adults, known as autoimmune Addison’s disease (AAD). Autoantibodies against 21-hydroxylase are a hallmark of AAD but are absent in some patients diagnosed with AAD, posing a challenge to their clinical management. METHODS. We tested a polygenic risk score for AAD (PRS14AAD) to prioritize seronegative patients for etiologic reevaluation. The PRS14AAD was calculated in patients diagnosed with AAD but lacking 21-hydroxylase autoantibodies (n = 124). Patients with low (n = 35) or high (n = 10) genetic susceptibility to AAD underwent clinical re-evaluation and whole-genome sequencing. RESULTS. Of the 34 patients with low PRS14AAD, 14 (41%) were re-diagnosed with non-autoimmune adrenal insufficiency, whereas no alternative etiologies were identified in patients with high PRS14AAD. The low PRS group included six patients (17%) with confirmed monogenic PAI and eight patients (23%) with adrenal insufficiency due to either tuberculosis or non-primary causes. Notably, four of the six confirmed monogenic cases developed PAI in adulthood, consistent with late-onset disease caused by hypomorphic variants. Additionally, seven patients (20%) carried genetic variants suspected of causing monogenic disease. CONCLUSION. These findings support considering genetic evaluation in patients with seronegative PAI, regardless of the age at diagnosis.
Maribel Aranda-Guillén, Ileana Ruxandra Botusan, Venuja Fernando, Michela Barbaro, Maria Blomqvist, Ellen Christine Røyrvik, Anette Susanne Bøe Wolff, Eystein Sverre Husebye, Stephan Kemp, Anna Wedell, Olov Ekwall, Magnus Isaksson, Jeanette Wahlberg, Ola Lindgren, Jakob Skov, Ragnhildur Bergthorsdottir, Per Dahlqvist, Sophie Bensing, Olle Kämpe, Daniel Eriksson
D1-type receptor (D1R)-mediated dopaminergic signaling within the nucleus accumbens shell (NAcSh) is essential for forming adaptive circuit changes that embed persistent memories associated with drug seeking and craving. While D1R is expressed in both NAcSh neurons and astrocytes, the specific contribution of astrocytic D1R to drug-related circuit plasticity remains poorly understood. Here, we demonstrated in mouse NAcSh slices that D1R agonists increased astrocytic Ca2+ activity, an effect that was attenuated by astrocyte-specific D1R knockdown. Furthermore, selective knockdown of astrocytic D1R in the NAcSh prior to cocaine self-administration inhibited cocaine-induced generation of silent synapses, thereby hampering the associated remodeling of NAcSh circuits. Behaviorally, knockdown of NAcSh astrocytic D1R expedited the extinction of cocaine seeking and reduced cue-induced reinstatement. These results identified astrocytic D1R as a fundamental component of NAcSh dopamine signaling during cocaine experience that remodeled synaptic connections and neural networks underlying drug seeking and relapse.
Shi Yan, Qize Li, Yao Wang, Wanqiu Chen, Zhong Chen, Alexander K. Zinsmaier, Paloma R. Huguet, Zhengsong Lu, Xiguang Qi, Zheng Xu, Yi Han, Gouri Sharma, Charles Wang, Eric J. Nestler, Oliver M. Schlüter, Yan Dong
Golgin-45 (G45) is a coiled-coil protein that transits reversibly between the Golgi and nucleus. In the Golgi, G45 serves as a tether for effectors of a pro-tumorigenic secretory program, but its nuclear role remains unclear. Here, we report that, upon entering the nucleus, G45 functions as a basic leucine zipper transcription factor. From genomic mapping, RNA-sequencing, and functional validation studies, we identify G45-binding sites and show that nuclear G45 can function as a transcriptional activator or repressor, a versatility enabled by phase separation into nuclear bodies enriched in transcriptional co-regulators. In lung cancer models, Golgi-docking reinforces, whereas nuclear translocation opposes, pro-tumorigenic activity of G45. Nuclear G45 incorporates into dimeric transcription factors that silence pro-tumorigenic secreted cargos. Epigenetic events in lung cancer degrade nuclear G45 and sequester G45 in the Golgi, which unleashes malignant secretion. Thus, inter-organelle transitions govern a G45-dependent secretory axis that drives lung cancer progression.
Chao Wu, Abhishek Kumar, Shike Wang, Weina Zhao, Yuanxin Xi, Jing Wang, Abhinav K. Jain, William K. Russell, Hou-fu Guo, Xiaochao Tan, Jonathan M. Kurie
Breast cancer is the most common cancer in women worldwide, with more than 2 million women diagnosed each year. This series of reviews, curated by Dr. Rinath Jeselsohn, highlights recent breakthroughs in therapeutic development that are changing the outlook for breast cancer patients, including improvements in immunotherapy, antibody-drug conjugates, endocrine therapies, and kinase inhibitors.
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