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Abstract
Fanconi anemia (FA) is the most common bone marrow failure (BMF) syndrome. Beyond a role in DNA repair, FA genes have a role in suppressing DNA-RNA hybrids, termed R-loops, which can be generated via RNA polymerase (RNAP)-mediated transcription. However, how these processes, including a role in fate determination of hematopoietic stem cells (HSCs), are related to BMF is largely unknown. Additionally, single FA gene knockouts in mice do not recapitulate most phenotypes observed in FA patients. Thus, we generated a mouse model for FA by introducing heterozygous Setd2, which restricts RNAP-dependent transcription. Here, we show that FA patient-derived cells and Setd2+/– Fanca–/– HSCs share increased R-loop as well as dsRNA levels, and a ribosomal biogenesis defect. Further, Setd2+/– Fanca–/– HSCs display cell cycle arrest, mitotic errors and BMF phenotypes. Importantly, utilizing our Setd2+/– Fanca–/– mice, we discovered that Juglone, a pan RNAP inhibitor, reduces R-loop and dsRNA and reverses ribosomal biogenesis defects and mitotic errors, thereby rescuing BMF. In conclusion, this study establishes a novel mouse model that underscores a key role for R-loop formation, ribosomal biogenesis defects and mitotic errors in HSCs in driving BMF in Fanconi anemia. We also introduce a potential therapeutic avenue based upon pan-inhibition of RNA polymerases utilizing Juglone.
Authors
Michihiro Hashimoto, Xiaomin Feng, Jie Bai, Huimin Zeng, Tian Li, Jue Li, Terumasa Umemoto, Paul R. Andreassen, Gang Huang
Abstract
Improper light focus on the retina, refractive error, is primarily caused by eye size differences and is the leading cause of vision loss worldwide. C-terminal variants in the Myelin Regulatory Factor (MYRF) gene, a retinal pigment epithelium (RPE)-derived transcription factor, lead to isolated nanophthalmos characterized by a small, though structurally sound eye. However, other MYRF loss-of-function variants cause syndromic disease. To address this discrepancy, in vitro and animal studies were performed on a pathogenic C-terminal variant dG-MYRF (p.Gly1126fs30*, c.3376-1G>A). Human RPE-cells or primary RPE transduced with dG-MYRF showed reduced target gene expression, with decreased steady-state levels of the C-terminal cleavage product, but normal cleavage and localization. A homozygous humanized MYRF C-terminal mouse model (MyrfhumdG/humdG) was embryonic lethal by embryonic day (E) 18.5, while wildtype (MyrfhumWT/humWT) mice were viable. Single-cell RNA-seq from E17.5 MyrfhumdG/humdG and knockout RxCre;Myrffl/fl (E15.5 and P0) mice revealed shared differentially expressed genes, with decreased effect size in the MyrfhumdG/humdG eyes. These findings support dG-MYRF as a hypomorphic allele. Additionally, two MYRF splicing variants creating nonfunctional isoforms were found in families with isolated nanophthalmos. Overall, hypomorphic MYRF alleles underlie isolated nanophthalmos, supporting a tissue-specific threshold effect and highlighting unique roles for the MYRF C-terminus in the RPE.
Authors
Gabrielle M. Rozumek, Michelle L. Brinkmeier, Bin Guan, Su Qing Wang, Catherine Tower, Nina T. Yang, Rachel S. Lim, Dejuan Kong, Daniel Soden, Qitao Zhang, John Y.S. Han, Jason M.L. Miller, Lijin Dong, D. Ford Hannum, Sayoko E. Moroi, Julia E. Richards, Robert B. Hufnagel, Lev Prasov
Abstract
Mitochondrial dysfunction devastates the heart in major cardiovascular diseases, yet the mechanisms governing mitochondrial quality control remain elusive. We discovered that TIGAR (TP53-induced glycolysis and apoptosis regulator) deficiency established profound cardiac protection through developmental epigenetic programming of Parkin expression. Using whole-body and cardiomyocyte-specific TIGAR knockout mice, we demonstrated remarkable cardioprotection following myocardial infarction with maintained ejection fraction, and complete resistance to diet-induced cardiac hypertrophy despite comparable weight gain. TIGAR deficiency triggered dramatic increases in Parkin expression across all somatic tissues except testes, where Parkin levels remained extraordinarily high (100-fold greater than cardiac levels) regardless of TIGAR status, revealing tissue-specific regulatory mechanisms. This protection was entirely Parkin-dependent, as double knockout mice lost all cardioprotective benefits. Crucially, adult TIGAR manipulation failed to alter Parkin levels, demonstrating that this pathway operated exclusively during critical developmental windows to program lifelong cardiac resilience. Whole-genome bisulfite sequencing identified reduced DNA methylation in Prkn intron 10 as the key regulatory mechanism, with CRISPR deletion dramatically increased Parkin expression in multiple cell lines. Our findings reveiled how early cardiac metabolism programmed lifelong cardiac function through epigenetic mechanisms, and identifyied developmental metabolic programming as a potential therapeutic target for preventing both ischemic heart disease and metabolic cardiomyopathy.
Authors
Yan Tang, Stanislovas S. Jankauskas, Li Liu, Xujun Wang, Alus M. Xiaoli, Fajun Yang, Gaetano Santulli, Daorong Feng, Jeffrey E. Pessin
Abstract
The cardiac conduction system (CCS) develops asymmetrically along the body axes. In heterotaxy syndrome—resulting from aberrant left–right (L–R) axis formation—atrial and atrioventricular conduction defects can cause life-threatening arrhythmias. However, the developmental mechanisms regulating the atrioventricular conduction system (AVCS) disposition and integrity remain unclear. To investigate the etiology of AVCS malformations in laterality defects, we analyzed CCS development and function in mouse mutants for Cryptic and Lefty1, which are key regulators of Pitx2 in the L–R axis formation. Cryptic–/– embryos exhibited bilateral sinoatrial (SA) nodes and an ectopic anterior AV node and bundle accompanied by reduced Pitx2 expression. In contrast, Lefty1–/– embryos showed a hypoplastic SA node and AV node–bundle dissociation with ectopic Pitx2 expression. Single-cell transcriptomic analysis of Pitx2–/– hearts revealed expansion of AV node and bundle populations, consistent with a repressive role of Pitx2 in AVCS specification. Genetic lineage tracing indicated that Pitx2-expressing cells from the left lateral plate mesoderm populate cranioventral cardiac regions, where AVCS development is suppressed. Together, these findings clarify how global L–R axis information is locally integrated to shape AVCS disposition and integrity, providing a mechanistic model for AVCS abnormalities in laterality-associated congenital heart disease.
Authors
Kunihiko Joo, Ryohei Matsuoka, Keiko Kitajima, Kenta Yashiro, Akira Shiose, Ryuji Tominaga, Michael M. Shen, Shinya Oki, Chikara Meno
Abstract
Synthetic prostaglandin analogues, such as latanoprost, are first-line treatments to reduce intraocular pressure (IOP) in the management of glaucoma, treating millions of patients daily. Glaucoma is a leading cause of blindness, characterized by progressive optic neuropathy, with elevated IOP being the sole modifiable risk factor. Despite this importance, the underlying latanoprost mechanism of action is still not well defined, being associated with both acute and long term activities, and a growing list of ocular side effects. Prostaglandins are eicosanoid lipid mediators. Yet, there has not been a comprehensive assessment of small lipid mediators in glaucomatous eyes. Here we performed a lipidomic screen of aqueous humour sampled from glaucoma patients and healthy control eyes. The resulting signature was surprisingly focused on significantly elevated levels of arachidonic acid (AA) and its derivative, the ant-inflammatory and cytoprotective mediator, lipoxin A4 (LXA4) in glaucoma eyes. Subsequent experiments reveal that this response is drug-induced, due to latanoprost actions on trabecular meshwork cells, rather than a consequence of elevated IOP. We demonstrate that increased LXA4 inhibits pro-inflammatory cues and promotes TGF-β production in the anterior chamber. In concert, an autocrine prostaglandin circuit mediates canonical rapid IOP-lowering. This work reveals parallel mechanisms underlying acute and long-term latanoprost activities during glaucoma treatment.
Authors
David J. Mathew, Shubham Maurya, Julian Ho, Izhar Livne-Bar, Darren Chan, Jenny Wanyu Zhang, Yvonne M. Buys, Marisa Sit, Graham Trope, Donna M. Peters, John G. Flanagan, Karsten Gronert, Jeremy M. Sivak
Abstract
Fontan-associated liver disease (FALD) is a frequent complication in single ventricle patients palliated with the Fontan operation. FALD severity can impact clinical decisions; however, the pathophysiology of FALD progression is unknown. Single-cell spatial transcriptomics (ST) was performed on liver explant tissue sections from FALD patients with early (n=1) and advanced fibrosis (n=1) using CosMxTM Spatial Molecular Imaging with in-situ hybridization of 6000 genes. Immunofluorescence for liver zonation and cellular stress markers was performed to confirm protein expression based on ST analysis in additional FALD tissues (n=18). Unbiased clustering yielded 12 liver cell types, comprising six subtypes of hepatocytes. FALD with advanced fibrosis demonstrated expansion of mid-zonal hepatocytes, accompanied by loss of zonal markers characteristic of canonical pericentral and periportal hepatocytes. A subset of hepatocytes in advanced FALD demonstrated increased cellular stress and a redundant zonal phenotype, which we have termed zonally ambiguous and stressed hepatocytes. CellChat analysis revealed that ectopic WNT2 signaling is likely driving disrupted hepatocyte zonation. To corroborate these bioinformatic findings, we performed immunofluorescence staining of FALD specimens, which confirmed a disruption of liver zonation, and a significant increase in heat shock protein 70 (HSP70). Lastly, HSP70 expression strongly correlated with the Congestive Hepatic Fibrosis (CHF) score. Thus, single-cell ST has identified a unique population of hepatocytes with features of cellular stress and redundant zonal gene expression specific to advanced FALD. Further studies on hepatocyte metabolic function in Fontan patients will lead to a greater understanding of FALD development and progression during chronic maladaptation.
Authors
Brandon M. Lehrich, Jordann N. Lewis, Vik Meadows, Lori Schmitt, Mylarappa B. Ningappa, Jia-Jun Liu, Silvia Liu, Catherine K. Gestrich, Victor O. Morell, Rakesh Sindhi, Satdarshan P. Monga, Anita Saraf
Abstract
Authors
Johanna Tennigkeit, Maurice Wiegelmann, Chiara Massa, Jonas Lübcke, Werner Dammermann, Karina Börner, Filip Schröter, Barbara Seliger, Maximilian Kleinert, Oliver Ritter, Gregor Sachse
Abstract
Heart failure (HF) persists as the primary cause of death among patients recovering from acute myocardial infarction (AMI). Protein ubiquitination has been implicated as a key modulator of HF pathogenesis, yet the role of ubiquitination in the Aldh2 rs671 mutant—the most common single-nucleotide variant in human populations—remains poorly understood. We discovered TRIM21 as a previously unrecognized E3 ubiquitin ligase for the ALDH2 rs671 mutant and elucidated its mechanistic involvement in HF progression. Using Aldh2 bone marrow chimeric mice to model AMI, we observed that wild-type mice transplanted with Aldh2 rs671 donor bone marrow developed severe myocardial fibrosis and markedly reduced cardiac systolic function two weeks post-infarction compared to controls. This phenotype arose from defective macrophage efferocytosis caused by myeloid-specific Aldh2 rs671 mutation. Through high-resolution mass spectrometry proteomics, we identified TRIM21 as the E3 ligase targeting ALDH2. TRIM21 catalyzed K48-linked ubiquitination at ALDH2 lysine 73. Macrophage-specific Trim21 knockdown via AAV-shTrim21 reversed both the exacerbated cardiac fibrosis and systolic dysfunction by restoring macrophage efferocytosis. These findings delineate the upstream E3 ubiquitin ligase and the ubiquitination site of ALDH2, revealing a potential therapeutic target for HF.
Authors
Tianrui Han, Xin Wen, Yunyun Guo, Xiangkai Zhao, Jian Zhang, Yuguo Chen, Feng Xu
Abstract
Alveolar macrophages (AMs) catabolize lipid-rich pulmonary surfactant to support gas exchange and have anti-inflammatory programming to limit tissue damage in response to minor challenges. GATA transcription factors (TFs) shape immune cell fates and GATA2 is expressed in a lung-specific manner in macrophages. GATA2 mutations and lung macrophage downregulation of GATA2 have been associated with chronic pulmonary pathologies in humans, but the role of GATA2 in coordinating AM function is not well defined. Using mice with myeloid-specific deletion of the GATA2 DNA binding C-terminal zinc finger domain, we show that GATA2 deficiency promotes enhanced inflammatory gene expression and metabolic dysfunction in AMs in response to type 2 stimuli. While homeostatic functions of AMs remain largely intact, GATA2 deficiency increases expression of type 2 response genes during IL-33-induced inflammation. Coincident with GATA2-dependent expression of genes in metabolic pathways, seahorse metabolic flux analysis indicates that AM metabolism is compromised in the absence of GATA2. AM GATA2-dependent gene networks are enriched for targets of TFs previously demonstrated to interact with GATA2 in other cellular contexts, including PU.1, PPARγ, and other regulators of AM function. Our data suggest that GATA2 modulates AM metabolic and transcriptomic programming to restrain responses and maintain AM identity during inflammation.
Authors
Morgan Jackson-Strong, Satarupa Ganguly, Aaron Francis, Flavia Rago, Jitendra Kanshana, Brandon A. Michalides, Lihong Teng, Omkar S. Betsur, Sonia Kruszelnicki, Karsen E. Shoger, Aaron Kim, Kay Bajpai, Amina Suleyman, Abigail Sekyere, Mika Hara, Varsha Sriram, Alok Kumar, Greg M. Delgoffe, Niranjana Natarajan, John F. Alcorn, Alison B. Kohan, Rachel A. Gottschalk
Abstract
The biological mechanisms underlying long COVID in the pediatric population are poorly understood. Our study aimed to characterize the immune pathophysiology of long COVID in children and young people (CYP). We analyzed major immune cell compartments in PBMCs, as well as specific SARS-CoV-2 antibody response in CYP with (n=99) and without (n=18) long COVID at three months following acute infection. Our findings indicate that pediatric long COVID is associated with a dysregulated immune response characterized by altered innate immunity and overactivated T-, B- and NK-cell responses. Furthermore, CYP with long COVID had an impaired humoral response to SARS-CoV-2 marked by a dysregulated B-cell compartment and lower levels of anti-RBD IgG and IgA. This correlated with reduced neutralizing capacity against SARS-CoV-2. Random forest analysis identified CCR6 expression on myeloid cells as the most relevant biomarker that distinguishes long COVID from control individuals with 79% accuracy.
Authors
Jon Izquierdo-Pujol, Núria Pedreño-Lopez, Tetyana Pidkova, Maria Nevot, Victor Urrea, Fernando Laguía, Francisco Muñoz-López, Judith Dalmau, Alba Gonzalez-Aumatell, Clara Carreras-Abad, María Méndez, Carlos Rodrigo, Marta Massanella, Julià Blanco, Jorge Carrillo, Benjamin Trinité, Javier Martinez-Picado, Sara Morón-López
Abstract
BACKGROUND. To construct multi-trait polygenic scores (PRS) predicting chronic obstructive pulmonary disease (COPD) and exacerbations, validate their performance in diverse cohorts, and identify PRS-related proteins for potential therapeutic targeting. METHODS. PRSmix+, a multi-trait PRS framework, is used to train a composite PRS (PRSmulti) in COPDGene non-Hispanic white participants (n=6,647). Associations of PRSmulti with COPD status (GOLD 2-4 vs. GOLD 0 or ICD) and exacerbation frequency were tested in COPDGene African American (n=2,466), ECLIPSE (n=1,858), MassGeneral Brigham Biobank (n=15,152), and All of Us (n=118,566). Protein prediction models were applied to GWAS summary statistics from traits contributing to PRSmulti and were validated with proteomic data in COPDGene (n=5,173) and UK Biobank (n=5,012). RESULTS. PRSmix+ selected 7 traits for PRSmulti. In multivariable models, PRSmulti was associated with COPD status (meta-analysis random effects (RE) OR 1.58 [95% CI: 1.28-1.94]) and exacerbation frequency (meta-analysis RE beta 0.21 [95% CI: 0.11-0.31]), with higher effect sizes observed in smoking-enriched cohorts. PRSmulti outperformed traditional single-trait PRS in all tested cohorts. Using protein prediction models, we identified 73 proteins associated with the PRS that were also validated with measured protein levels in COPDGene and UK biobank. Of these proteins, 25 were linked to approved or investigational drugs. Notable targets include RAGE/sRAGE, IL1RL1, and SCARF2, all implicated in COPD pathogenesis and exacerbations. CONCLUSIONS. Multi-trait PRS improves prediction of COPD and exacerbation risk. Integration with proteomic data identifies druggable protein targets, offering a promising avenue for precision medicine in COPD management. TRIAL REGISTRATION. COPDGene: NCT00608764; ECLIPSE: NCT00292552.
Authors
Chengyue Zhang, Iain R. Konigsberg, Yixuan He, Jingzhou Zhang, Tinashe Chikowore, William B. Feldman, Xiaowei Hu, Yi Ding, Bogdan Pasaniuc, Diana Chang, Qingwen Chen, Jessica A. Lasky-Su, Julian Hecker, Martin D. Tobin, Jing Chen, Sean Kalra, Katherine A. Pratte, Hae Kyung Im, Emily S. Wan, Ani Manichaikul, Edwin K. Silverman, Russell P. Bowler, Leslie A. Lange, Victor E. Ortega, Alicia R. Martin, Michael H. Cho, Matthew R. Moll
Abstract
Authors
Sebastian Kämpf, Marjan Hematianlarki, Leon Altmann, Jessica M. Bright, Alyssa M. A. Toda, Zohreh Mirzapoor, Valentin Zollner, Anja Werner, Johanna Bulang, Barbara Radovani, Miriam Wöhner, William Avery, Mark J. Karbarz, Pamela B. Conley, Greg P. Coffey, Falk Nimmerjahn
Abstract
Dual-degree medical students pursue additional training to prepare for careers in research, public health, and administration, but how these experiences influence residency application behaviors and outcomes are poorly understood. We analyzed 36,298 residency applicants from the TexasSTAR database spanning 2017-2023 to compare application, interview, and match patterns among single-degree MD applicants and those with MD-PhD, MD-MPH, MD-MBA, or MD-MSc degrees. Despite differences in academic metrics, application strategies, and interview rates, match rates were similar across degree groups. MD-PhD students applied to fewer programs but had the highest interview offer-to-application rate and matched at more prestigious programs based on Doximity rankings. Beyond traditional application metrics such as board scores, research productivity, grades, and honor society membership, strategies including away rotations, geographic preferencing, and program signaling were associated with increased interview offers and match success among all applicants but were less influential for dual-degree applicants. These findings suggest dual-degree applicants require specialized advising and evaluation.
Authors
Daniel C. Brock, Deborah D. Rupert, Toni Darville, Caroline S. Jansen, Elias M. Wisdom, Cynthia Y. Tang
Abstract
Angiopoietin-2 (ANGPT2) is known to destabilize vascular barriers in most peripheral organs; however, its role in the brain vasculature remains poorly understood. To investigate its physiological function within the brain vasculature, we analyzed constitutive Angpt2 knockout (KO) mice in adulthood. We showed that loss of ANGPT2 leads to region-specific vascular malformations and blood-brain barrier (BBB) dysfunction, resulting in differential permeability to 1 kDa and 70 kDa fluorescent tracers. Notably, overt vascular malformations appeared only in select brain regions that allowed leakage of both tracers. These malformations were characterized by dilated, intertwined, and sprouting endothelial cells, surrounded by reactive perivascular cells, along with high levels of astrocyte- and neuron-derived vascular endothelial growth factor A (VEGFA) and elevated expression of the vascular receptors VEGF receptor 2 (KDR) and neuropilin 1 (NRP1). Other cortical areas without obvious malformations exhibited significant leakage of the 1 kDa tracer. We also demonstrated that different cell types took up the tracers after passing the BBB. Our findings identified ANGPT2 as an important factor involved in the regulation of cerebrovascular architecture, barrier integrity, and endothelial–parenchymal interactions, and uncovered surprising differences in the leakage patterns and cellular uptake of two widely used BBB tracers.
Authors
Weihan Li, Elisa Vázquez-Liébanas, Chanaëlle Fébrissy, Florent Sauvé, Jianhao Wang, Doğan Emre Sayıner, Pia Buslaps, Amanda Norrén, Michael Vanlandewijck, Liqun He, Marie Jeansson, Lars Muhl, Maarja Andaloussi Mäe
Abstract
Pancreatic cancer is a highly innervated gastrointestinal disease in which sympathetic nerves play a critical role in modulating tumor growth and the tumor microenvironment (TME). While recent studies suggest that sympathetic nerves influence various TME components, including lymphoid and myeloid immune cells, their interactions with cancer-associated fibroblasts (CAFs) remain poorly understood. CAFs are a hallmark of pancreatic tumors and are known to upregulate axon guidance and neuroactive cues, suggesting a potential feedback loop with tumor-innervating nerves. Here, we investigated the bidirectional crosstalk between sympathetic nerves and CAFs in human and mouse pancreatic tumors. Using a chemo-genetic ablation model, we selectively eliminated pancreatic sympathetic nerves and found that denervation significantly reduced tumor size in female mice. To further dissect this interaction, we established co-culture systems with immortalized pancreatic fibroblasts and primary sympathetic neuron explants, identifying key transcriptional changes driven by CAF-sympathetic nerve signaling. Our findings demonstrated that sympathetic signaling enhanced CAF activation and extracellular matrix remodeling, while activated CAFs, in turn, induced transcriptional programs in sympathetic neurons associated with nerve injury response. These results establish CAFs as central mediators of the tumor-supportive role of sympathetic nerves, offering further insights into the neural regulation of pancreatic cancer progression.
Authors
Ariana L. Sattler, Parham Diba, Kevin Hawthorne, Carl Pelz, Joe Grieco, Tetiana Korzun, Bryan Chong, M.J. Kuykendall, Rosalie C. Sears, Daniel L. Marks, Mara H. Sherman, Teresa A Zimmers, S. Ece Eksi
Abstract
Dermal fibrosis is a cardinal feature of systemic sclerosis (SSc) for which there are limited Systemic sclerosis (SSc) is characterized by dermal fibrosis accompanied by loss of dermal white adipose tissue (DWAT), yet the mechanisms linking adipocyte depletion to fibroblast activation remain unclear. Here we identify the transcription factor SIX1 as a central regulator coupling adipogenic repression with profibrotic signaling. SIX1 expression was increased in skin biopsies from two independent SSc cohorts and localized to fibroblast and perivascular stromal cells. In mice, ubiquitous or adipocyte-specific deletion of Six1 preserved DWAT, reduced collagen accumulation, and selectively decreased pro-fibrotic mediators. In cultured fibroblasts, CRISPR/Cas9-mediated Six1 loss enhanced adipogenic markers while reducing profibrotic mediators and directly suppressed PAI-1 (SERPINE1) promoter activity. Together, these data position SIX1 as a transcriptional switch that promotes adipocyte reprogramming and fibrotic progression, and highlight SIX1 inhibition as a potential therapeutic strategy to preserve adipocyte identity and limit dermal fibrosis.
Authors
Nancy Wareing, Tingting W. Mills, Scott Collum, Minghua Wu, Lucy Revercomb, René Girard, Hui Liu, Alexes Daquinag, Mikhail Kolonin, Marka Lyons, Brian Skaug, Weizhen Bi, Meer A. Ali, Haniyeh Koochak, Anthony R. Flores, Yuntao Yang, W. Jim Zheng, William R. Swindell, Shervin Assassi, Harry Karmouty-Quintana
Abstract
Adeno-associated viruses (AAVs) have been used in gene therapy, especially for inherited retinal diseases. Despite their effectiveness in gene transduction, immune responses to the AAV capsid and transgene products have been reported, which can compromise both the efficacy and safety of AAV-mediated therapies. The eye is regarded as an immune-privileged organ where immune activity is constitutively suppressed. Here, we highlight that immunomonitoring in an ocular gene transfer reveals variable immune responses, whatever the species (human clinical trial, non-human primates, mice), the site of injection, the cassette, and the dose. We further explored factors contributing to this variability, investigating the potential correlation among immune parameters in a controlled experimental setting. In a syngeneic murine model after a subretinal injection of AAV, our results highlight an inter-individual variability of immune parameters, emphasizing the importance of considering inherent variability among individuals while designing personalized therapies.
Authors
Duohao REN, Gaelle A. CHAUVEAU, Julie VENDOMELE, Emilie CABON, Audrey PINEIRO, Catherine VIGNAL-CLERMONT, Hanadi SALIBA, Giuseppe RONZITTI, Anne GALY, Deniz DALKARA, Juliette PULMAN, Divya AIL, Sylvain FISSON
Abstract
Oxidative signaling is a central mechanism in alcohol-induced injury and has a strong implication in blood-brain barrier (BBB) dysregulation and neuroinflammation. Here, by targeting oxidative signaling, we hypothesized an innovative approach to develop a clinically relevant therapeutic strategy for alleviating alcohol-mediated neurovascular damage. To accomplish this, we enhanced the endogenous activity of Nrf2 (nuclear factor E2-related factor 2) by treating with an Nrf2 activator III TAT peptide (Nrf2 peptide, NP) and investigated the neuroprotective role of Nrf2 in promoting antioxidant defense properties and reducing BBB damage and transmigration of leukocytes to the brain following alcohol ingestion. We administered the NP subcutaneously to alcohol-ingested mice and evaluated its therapeutic potential in alleviating alcohol-associated neurovascular impairments. We compared the results with control peptide (random sequence with TAT)-treated animals. The studies showed that the NP treatment preserved the oxidant-antioxidant balance, downregulated ICAM-1 and its receptors, and mitigated BBB damage and leukocyte infiltration into the brain. We validated the effect of the NP in Nrf2 knock-out (KO) mice (Nrf2−/−). Thus, this study demonstrates NP’s neurovascular protective effects by regulating the oxidant-antioxidant balance, reducing oxidative stress-induced BBB disruption, and limiting transmigration of immune cells to the brain in a mouse model of alcohol ingestion.
Authors
Bibhuti B. Saikia, Saleena Alikunju, Yemin A. Poovanthodi, Zayan Kassim, P. M. Abdul Muneer
Abstract
Systemic sclerosis (SSc) is a complex and heterogeneous condition characterized by progressive fibrosis in multiple organs. Recent studies implicate plasminogen activator inhibitor 1 (PAI-1) in the pathogenesis of SSc, and PAI-1 is considered as a potential target for therapy. Here, using single-cell and spatial RNA-seq analysis of skin biopsies from 18 healthy individuals and 22 SSc patients, we found elevated PAI-1 co-localizing to myofibroblasts with enriched extracellular matrix-associated biological processes. Treatment of SSc dermal fibroblasts with the small molecule PAI-1 inhibitor MDI-2517 reduced the expression of the profibrotic markers COL1A1 and ACTA2. To investigate the therapeutic potential of MDI-2517, we evaluated its efficacy in reducing fibrosis in a preclinical model of SSc. Treatment of mice with MDI-2517 significantly reduced both skin and lung fibrosis and was superior to treatment with either pirfenidone or mycophenolate mofetil. Additionally, MDI-2517 attenuated weight loss and significantly reduced the expression of key profibrotic markers. Compared to tiplaxtinin, another PAI-1 inhibitor previously shown to be effective in a model of SSc, MDI-2517 was found to have superior efficacy at a 10-fold lower dose. These findings highlight the role of PAI-1 in the pathogenesis of SSc, and the potential of MDI-2517 for the treatment of SSc.
Authors
Enming J. Su, Pei-Suen Tsou, Mark Warnock, Natalya Subbotina, Kris Mann, Sirapa Vichaikul, Alyssa Rosek, Lisa Leung, Xianying Xing, Enze Xing, Olesya Plazyo, Rachael Bogle, Lam C. Tsoi, Cory D. Emal, Dinesh Khanna, John Varga, Thomas H. Sisson, Johann E. Gudjonsson, Daniel A. Lawrence
Abstract
Proper development of the umbilical cord and placental vasculature is essential for embryonic development. While the allantois is known give rise to endothelial cells (ECs) within the placenta, whether the allantois gives rise to ECs in the umbilical cord is debated. Furthermore, a lack of genetic tools to study placental vascular development independent of the embryo proper has hindered robust investigation into the primary cause of vascular defects from early studies utilizing global knockouts. In this study, we delineate the contribution of the allantois to the umbilical vessels and utilize a mouse genetic tool previously developed by our lab to revisit the role of Notch signaling during placental development. We show that the allantois has mosaic contribution to the umbilical endothelium with higher contributions closer to the placenta. Allantoic deletion of Dll4 disrupts umbilical cord and placental vascular formation with secondary defects in the heart. Lastly, we identify Unc5b downstream of Notch signaling that restricts EC migration while promoting chemokine signaling for smooth muscle cell (SMC) recruitment to arteries. These findings identify a genetic tool for investigating placental vascular development and give new insights into the ontogeny and mechanisms of placental vascular and umbilical cord development.
Authors
Derek C. Sung, Hana A. Ahanger, Sweta Narayan, Jesse A. Pace, Mei Chen, Jisheng Yang, Siqi Gao, T.C.S. Keller IV, Jenna Bockman, Xiaowen Chen, Erica Nguyen, Alan T. Tang, Patricia Mericko-Ishizuka, Ivan Maillard, Mark L. Kahn
