Pediatric high-grade gliomas (pHGGs) are aggressive diseases with poor outcomes. The diverse molecular heterogeneity in these rare tumors and inadequate tumor models have limited the development of effective therapies. In this issue of the JCI, Haase et al. produced a genetically engineered mouse model of H3.3-G34R–mutant pHGG to help identify vulnerabilities in DNA repair pathways. The authors designed a therapy that combined radiation with DNA damage response inhibitors to induce an adaptive immune response and extend survival. These findings suggest that combinations of small-molecule therapies with immunotherapies could drive a more durable response and improve mortality for patients with pHGG.
Connor P. Hall, James C. Cronk, Jeffrey A. Rubens
Healthy individuals are generally immunologically tolerant to proteins derived from one’s self (termed self proteins). However, patients with monogenic clotting disorders, like hemophilia A (HemA), lack central tolerance to the absent self protein. Thus, when exposed to replacement therapy, such as procoagulant factor VIII, they may mount an immune response against the very self protein that is missing. In the current issue of the JCI, Becker-Gotot, Meissner, et al. present data on a possible mechanism for tolerance to factor VIII in healthy individuals and the immune response in patients, involving a role of PD-1 and T regulatory cells. The findings suggest that treatment with PD-1– and PD-1L–specific reagents may induce tolerance in patients with autoimmune disease, especially those with HemA who also possess inhibiting antibodies.
David W. Scott
The gastric oxyntic glands are maintained by gastric stem cells that continuously supply all differentiated cell types within the corpus epithelium. Stem cells are supported by stromal cells that make up the stem cell niche. In this issue of the JCI, Fischer et al. report on their use of genetically engineered mouse models and organoids to study the role of R-spondin 3 (RSPO3) in the stomach. RSPO3, one of the major stem cell niche factors, primarily promoted secretory differentiation in the normal stomach, but also contributed to regeneration following injury. Mechanistically, RSPO3 was upregulated in the stroma by loss of chief cells and then activated the YAP pathway in gastric stem and progenitor cells, which appeared to be critical for regeneration of the secretory lineage. These data substantially advance our understanding of the regulation of gastric stem cells and highlight a function for RSPO3 in the gastrointestinal tract, which is as the gatekeeper of secretory differentiation.
Ken Kurokawa, Timothy C. Wang, Yoku Hayakawa
Normal-tension glaucoma is a form of optic nerve degeneration that is characterized by loss of retinal ganglion cells independent of eye pressure elevation. In this issue of the JCI, Pan et al. report the discovery in a Japanese family of a mutation in the METTL23 gene, which encodes a DNA methyltransferase that causes normal-pressure glaucoma in haploinsufficiency. Inherited as an autosomal dominant condition, METTL23 deficiency revealed an important function in the regulation of pS2 and the downstream NF-κB signaling pathway, which has previously been linked to glaucomatous optic nerve degeneration. These findings are the first direct link between defective epigenetic regulatory machinery and genetic forms of optic nerve degeneration.
Wendy W. Liu, Yang Sun
Despite the clinical advances in managing metastatic prostate cancer in the last 20 years, treatments for patients with metastatic disease only offer a brief respite from disease progression, especially after first-line therapies. Research into treatment resistance has defined a subset of patients with neuroendocrine differentiation of their prostate adenocarcinoma. Although neuroendocrine findings in conjunction with prostate adenocarcinoma can be seen in pathology samples at all stages of disease, the neuroendocrine variant of prostate cancer associated with poor outcomes occurs in approximately 20% of men with advanced disease. In this issue of JCI, Zhao, Sperger, and colleagues present data for a promising biomarker platform that can detect neuroendocrine prostate cancer after serial sampling of patients’ blood with a high degree of sensitivity and specificity. This assay will be tested in several current and future trials to better define its potential clinical role and perhaps provide a greater understanding of neuroendocrine prostate cancer itself.
Fatima Karzai, Ravi A. Madan
Sterile α motif domain–containing 9 (SAMD9) and SAMD9-like (SAMD9L) syndromes are inherited bone marrow failure syndromes known for their frequent development of myelodysplastic syndrome with monosomy 7. In this issue of the JCI, Abdelhamed, Thomas, et al. report a mouse model with a hematopoietic cell–specific heterozygous Samd9l mutation knockin. This mouse model resembles human disease in many ways, including bone marrow failure and the nonrandom loss of the mutant allele. Samd9l-mutant hematopoietic stem progenitor cells showed reduced fitness at baseline, which was further exacerbated by inflammation. TGF-β hyperactivation was found to underlie reduced fitness, which was partially rescued by a TGF-β inhibitor. These findings illustrate the potential role of TGF-β inhibitors in the treatment of SAMD9/SAMD9L syndromes.
Arrhythmogenic cardiovascular disorders are associated with considerable morbidity and mortality. Whether cardiac conduction disease is caused by genetic defects, procedural perturbations, valvular disease, ischemia, aging, or heart failure, new therapies are warranted. In this issue of the JCI, Goodyer et al. used state-of-the-art technologies to image the cardiac conduction system (CCS) in real time and to deliver targeted therapies to the CCS and its subcomponents. These findings advance the ability to image and treat specific lineages within the adult heart with the potential for broader applications in the treatment of cardiovascular diseases.
Daniel J. Garry, Demetris Yannopoulos, Tamas Alexy
The current dogma of type 1 diabetes pathogenesis asserts that an autoimmune attack leads to the destruction of pancreatic β cells, with subsequent hyperglycemia. This dogma is based on islet autoantibodies emerging prior to the onset of type 1 diabetes. In this issue of the JCI, Warncke et al. report on their investigation of the development of hyperglycemia below the diabetes threshold as an early proxy of β cell demise. Surprisingly, they found that an elevation in blood glucose preceded the appearance of autoimmunity. This observation calls into question the importance of autoimmunity as the primary cause of β cell destruction and has implications for prevention and treatment in diabetes.
Marc Y. Donath
For patients and caregivers to be fully informed about how living organ donation or prior kidney injury affects future health, we need to better understand the role of kidney reserve in physiological adaptation, especially during pregnancy. Importantly, epidemiological studies reason that live kidney donors are at increased risk for developing preeclampsia, a hypertensive disorder of pregnancy with serious implications for maternal and fetal health. Despite the import of this finding, the mechanistic basis for this increased risk is not understood. In this issue of the JCI, Dupont, Berg, and co-authors provide strong evidence that impaired placental perfusion, placental ischemia, increased soluble fms-like tyrosine kinase 1 (sFLT1), and a maternal preeclampsia–like phenotype are associated with an inability to upregulate the l-tryptophan–derived l-kynurenine pathway during pregnancy in mice with blunted renal reserve. These surprising revelations underscore the curious quiddity of l-tryptophan.
Philip A. Marsden
With the advent of immune checkpoint blockade (ICB) therapy, treatment strategies for late-stage cancers have seen a radical advancement. In this issue of the JCI, Wang et al. characterize the functional role of miR-155 in breast cancer and its potential in harnessing the efficacy of immunotherapy. The study reports that high expression levels of miR-155 in breast cancer cells downregulated suppressor of cytokine signaling 1 (SOCS1), increased the phosphorylated STAT1 (pSTAT1)/pSTAT3 ratio, and thereby stimulated chemoattractants for tumor infiltration of effector T cells. Moreover, miR-155 overexpression set the stage for ICB therapy via increased programmed death ligand 1 (PD-L1) expression on cancer cells and enhanced immunological memory response via the release of miR-155–containing extracellular vesicles. Collectively, these data suggest that miR-155 is a strong candidate as a prognostic biomarker for ICB therapy.
Samantha Sharma, Mateusz Opyrchal, Xiongbin Lu
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