This issue marks the transition of JCI Insight’s Editorial Board to a new team led by Oliver Eickelberg and colleagues at the University of Pittsburgh. In his inaugural editorial, Dr. Eickelberg shares his vision for the next 5 years and plans to take the journal to even farther reaches.
Image credit: Oliver Eickelberg
Pulmonary veno-occlusive disease (PVOD) is a rare but severe form of pulmonary hypertension characterized by the obstruction of pulmonary arteries and veins, causing increased pulmonary artery pressure and leading to right ventricular (RV) heart failure. PVOD is often resistant to conventional pulmonary arterial hypertension (PAH) treatments and has a poor prognosis, with a median survival time of 2 to 3 years after diagnosis. We previously showed that the administration of a chemotherapy agent mitomycin C (MMC) in rats mediates PVOD through the activation of the eukaryotic initiation factor 2 (eIF2) kinase protein kinase R (PKR) and the integrated stress response (ISR), resulting in the impairment of vascular endothelial junctional structure and barrier function. Here, we demonstrate that aged rats over one year exhibit more severe vascular remodeling and RV hypertrophy than young adult rats following MMC treatment. This is attributed to an age-associated elevation of basal ISR activity and depletion of protein phosphatase 1, leading to prolonged eIF2 phosphorylation and sustained ISR activation. Pharmacological blockade of PKR or ISR mitigates PVOD phenotypes in both age groups, suggesting that targeting the PKR-ISR axis could be a potential therapeutic strategy for PVOD.
Amit Prabhakar, Meetu Wadhwa, Rahul Kumar, Prajakta Ghatpande, Aneta Gandjeva, Rubin M. Tuder, Brian B. Graham, Giorgio Lagna, Akiko Hata
Spinal muscular atrophy (SMA) is a recessive, developmental disorder caused by the genetic loss or mutation of the gene SMN1 (Survival of Motor Neuron 1). SMA is characterized by neuromuscular symptoms and muscle weakness. Several years ago, SMA treatment underwent a radical transformation, with the approval of three different SMN-dependent disease modifying therapies. This includes two SMN2 splicing therapies - Risdiplam and Nusinersen. One main challenge for Type II SMA patients treated with these drugs is ongoing muscle fatigue, limited mobility, and other skeletal problems. To date, few molecular studies have been conducted on SMA-patient derived tissues after treatment, limiting our understanding of what targets remain after the principal spinal cord targeted therapies are applied. Therefore, we collected paravertebral muscle from eight Type II patients undergoing spinal surgery for scoliosis and seven controls. We used RNA-sequencing to characterize their transcriptional profiles and correlate these with muscle histology. Despite the limited cohort size and heterogeneity, we observed a consistent loss of oxidative phosphorylation machinery of the mitochondria, a decrease in mitochondrial DNA copy number, and a correlation between signals of cellular stress, denervation and increased fibrosis. This work provides new putative targets for combination therapies for Type II SMA.
Fiorella Grandi, Stéphanie Astord, Sonia Pezet, Elèna Gidaja, Sabrina Mazzucchi, Maud Chapart, Stéphane Vasseur, Kamel Mamchaoui, Piera Smeriglio
Despite advances in sequencing technologies, a molecular diagnosis remains elusive in many Mendelian disease patients. Current short-read clinical sequencing approaches cannot provide chromosomal phase information or epigenetic information without further sample processing, which is not routinely done and can result in an incomplete molecular diagnosis in patients. The ability to provide phased genetic and epigenetic information from a single sequencing run would improve the diagnostic rate of Mendelian conditions. Here we describe Targeted Long-read Sequencing of Mendelian Disease genes (TaLon-SeqMD) using a real-time adaptive sequencing approach. Optimization of bioinformatic targeting enabled selective enrichment of multiple disease-causing regions of the human genome. Haplotype-resolved variant calling and simultaneous resolution of epigenetic base modification could be achieved in a single sequencing run. The TaLon-SeqMD approach was validated in a cohort of 18 subjects with previous genetic testing targeting 373 inherited retinal disease (IRD) genes, yielding the complete molecular diagnosis in each case. This approach was then applied in two IRD cases with inconclusive testing, which uncovered non-coding and structural variants that were difficult to characterize by standard short-read sequencing. Overall, these results demonstrate TaLon-SeqMD as an approach to provide rapid phased-variant calling to provide the molecular basis of Mendelian diseases.
Kenji Nakamichi, Jennifer Huey, Riccardo Sangermano, Emily M. Place, Kinga M. Bujakowska, Molly Marra, Lesley A. Everett, Paul Yang, Jennifer R. Chao, Russell N. Van Gelder, Debarshi Mustafi
Epstein Barr virus (EBV) contributes to around 2% of all tumors worldwide. Simultaneously, more than 90% of healthy human adults persistently carry EBV without clinical symptoms. In most EBV carriers it is thought that virus-induced tumorigenesis is prevented by cell-mediated immunity. Specifically, memory CD8+ T cells recognize EBV-infected cells during latent and lytic infection. Using a symptomatic primary infection model, similar to infectious mononucleosis (IM), we found EBV-induced CD8+ tissue-resident memory T cells (TRMs) in mice with a humanized immune system. These human TRMs were preferentially established after intranasal EBV infection in nasal-associated lymphoid tissues (NALT), equivalent to tonsils, the primary site of EBV infection in humans. They expressed canonical TRM markers, including CD69, CD103, and BLIMP-1, as well as Granzyme B, CD107a and CCL5. Despite cytotoxic activity and cytokine production ex vivo, these TRMs demonstrated reduced CD27 expression and proliferation and failed to control EBV viral loads in the NALT during infection although effector memory T cells (TEMs) controlled viral titers in spleen and blood. Overall, TRMs are established in mucosal lymphoid tissues by EBV infection, but primarily systemic CD8+ T cell expansion seems to control viral loads in the context of IM-like infection.
Daniel Kirchmeier, Yun Deng, Lisa Rieble, Michelle Böni, Fabienne Läderach, Patrick Schuhmachers, Alma Delia Valencia-Camargo, Anita Murer, Nicole Caduff, Bithi Chatterjee, Obinna Chijioke, Kyra Zens, Christian Münz
Immune cell mediated inflammation is important in normal tissue regeneration but can be pathologic in diabetic wounds. Limited literature exists on the role of CD4+T cells in normal or diabetic wound repair, however, the imbalance of CD4+TH17/Treg cells has been found to promote inflammation in other diabetic tissues. Here, using human tissue and murine transgenic models, we identified that the histone methyltransferase MLL1 directly regulates the TH17 transcription factor RORγ via an H3K4me3 mechanism and increases expression of Notch receptors and downstream Notch signaling. Further, we found that Notch receptor signaling regulates CD4+TH cell differentiation and is critical for normal wound repair, and loss of upstream Notch pathway mediators or receptors in CD4+T cells resulted in the loss of CD4+TH cell differentiation in wounds. In diabetes, MLL1 and Notch-receptor signaling were upregulated in wound CD4+TH cells, driving CD4+ T cells towards the TH17 cell phenotype. Treatment of diabetic wound CD4T cells with a small molecule inhibitor of MLL1 (MI-2) yielded a significant reduction in CD4+TH17 cells and IL17A. This is the first study to identify the MLL1-mediated mechanisms responsible for regulating the TH17/Treg balance in normal and diabetic wounds and define the complex role of Notch signaling in CD4+T cells in wounds, where increased or decreased Notch signaling both result in pathologic wound repair. Therapeutic targeting of MLL1 in diabetic CD4+TH cells may decrease pathologic inflammation through regulation of CD4+T cell differentiation.
William J. Melvin, Tyler M. Bauer, Kevin D. Magnum, Christopher O. Audu, James Shadiow, Emily Barrett, Amrita Joshi, Jadie Y. Moon, Rachel Bogel, Purba Mazumder, Sonya J. Wolf, Steven Kunkel, Johann E. Gudjonsson, Frank M. Davis, Katherine A. Gallagher