Radiotherapy induces a Type I interferon (T1IFN)-mediated anti-tumoral immune response that we hypothesized could be potentiated by a first-in-class ATM inhibitor leading to enhanced innate immune signaling, T1IFN expression, and sensitization to immunotherapy in pancreatic cancer. We evaluated the effects of AZD1390 or a structurally related compound AZD0156 on innate immune signaling and found that both inhibitors enhanced radiation-induced T1IFN expression via the POLIII/RIG-I/MAVS pathway. In immunocompetent syngeneic mouse models of pancreatic cancer, ATM inhibitor enhanced radiation-induced anti-tumoral immune responses and sensitized to anti-PD-L1, producing immunogenic memory and durable tumor control. Therapeutic responses were associated with increased intratumoral CD8+ T cell frequency and effector function. Tumor control was dependent on CD8+ T cells as therapeutic efficacy was blunted in CD8+ T cell-depleted mice. Adaptive immune responses to combination therapy provided systemic control of contralateral tumors outside of the radiation field. Taken together, we show that a clinical candidate ATM inhibitor enhances radiation-induced T1IFN leading to both innate and subsequent adaptive anti-tumoral immune responses and sensitization of otherwise resistant pancreatic cancer to immunotherapy.
Qiang Zhang, Long Jiang, Weiwei Wang, Amanda K. Huber, Victoria M. Valvo, Kassidy M. Jungles, Erin A. Holcomb, Ashley N. Pearson, Stephanie The, Zhuwen Wang, Leslie A. Parsels, Joshua D. Parsels, Daniel R. Wahl, Arvind Rao, Vaibhav Sahai, Theodore S. Lawrence, Michael D. Green, Meredith A. Morgan
Patients with mutations in the thyroid hormone (TH) cell transporter MCT8 gene develop severe neuro-psychomotor retardation known as the Allan-Herndon-Dudley syndrome (AHDS). It is assumed that this is caused by a reduction in TH signaling in the developing brain, and treatment remains understandably challenging. Given species differences in brain TH transporters and the limitations of studies in mice, we generated brain organoids (BOs) using human iPSCs from MCT8-deficient patients. We found that MCT8-deficient BOs exhibit (i) impaired T3 transport in developing neural cells, as assessed through deiodinase-3-mediated T3 catabolism, (ii) reduced expression of genes involved in neurogenesis and neuronal maturation, and (iii) reduced T3-inducibility of TH-regulated genes. In contrast, the TH-analogs 3,5-diiodothyropropionic acid and 3,3’,5-triiodothyroacetic acid triggered normal responses (induction/repression of T3-responsive genes) in MCT8-deficient BOs, constituting a proof-of-concept that lack of T3 transport underlies the pathophysiology of AHDS, demonstrating the clinical potential for TH analogues to be used in treating AHDS patients. MCT8-deficient BOs represent a species-specific relevant preclinical model that can be utilized to screen drugs with potential benefits as personalized therapeutics for AHDS patients.
Federico Salas-Lucia, Sergio Escamilla, Antonio C. Bianco, Alexandra Dumitrescu, Samuel Refetoff
Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene lead to cystic fibrosis (CF), a life-threating autosomal recessive genetic disease. While recently approved Trikafta dramatically ameliorates CF lung diseases, there is still a lack of effective medicine to treat CF-associated liver disease (CFLD). To address this medical need, we used a recently established CF rabbit model to test if Sotagliflozin, a Sodium-Glucose cotransporter 1 and 2 (SGLT1/2) inhibitor drug that is approved to treat diabetes, can be repurposed to treat CFLD. Sotagliflozin treatment led to systemic benefits to CF rabbits, evidenced by increased appetite and weight gain as well as prolonged lifespan. For CF liver related phenotypes, the animals benefited from normalized blood chemistry and bile acid parameters. Further, Sotagliflozin alleviated non-alcoholic steatohepatitis (NASH)-like phenotypes including liver fibrosis. Intriguingly, Sotagliflozin treatment markedly reduced the otherwise elevated endoplasmic reticulum (ER) stress responses in the liver and other affected organs of CF rabbits. In summary, our work demonstrates that Sotagliflozin attenuates liver disorders in CF rabbits, and merits Sotagliflozin as a potential drug to treat CFLD.
Xiubin Liang, Xia Hou, Mohamad Bouhamdan, Yifei Sun, Zhenfeng Song, Carthic Rajagopalan, Hong Jiang, Hong-Guang Wei, Jun Song, Dongshan Yang, Yanhong Guo, Yihan Zhang, Hongmei Mou, Jifeng Zhang, Y. Eugene Chen, Fei Sun, Jian-Ping Jin, Kezhong Zhang, Jie Xu
In humans, Type 2 Diabetes Mellitus (T2DM) shows a higher prevalence in men compared to women, phenotype that has been attributed to a lower peripheral insulin sensitivity in men. Whether sex-specific differences in pancreatic β-cell function also contribute is largely unknown. Here we characterized the electrophysiological properties of β-cells in intact mouse male and female islets. Elevation of glucose concentration above 5 mM triggers an electrical activity with a similar glucose dependence in β-cells of both sexes. However, female β-cells have a more depolarized membrane potential and increased firing frequency compared to males. The higher membrane depolarization in female β-cells is caused by ~50% smaller Kv2.1 K+ currents compared to males but otherwise unchanged KATP, Ca2+-activated BK and SK, and background TASK1/TALK1 K+ current densities. In female β-cells the higher depolarization causes a membrane potential-dependent inactivation of the voltage-gated Ca2+ channels (CaV) resulting in reduced Ca2+ entry. Nevertheless, this reduced Ca2+ influx is offset by the higher action potential firing frequency. Since exocytosis of insulin granules does not show a sex-specific difference we conclude that the higher electrical activity promotes insulin release in females improving glucose tolerance.
Noelia Jacobo-Piqueras, Tamara Theiner, Stefanie M. Geisler, Petronel Tuluc
Fibroblasts are stromal cells known to regulate local immune responses important for wound healing and scar formation; however, the cellular mechanisms driving damage and scarring in cutaneous lupus erythematosus (CLE) patients remain poorly understood. Dermal fibroblasts in systemic lupus erythematosus (SLE) patients are abnormally exposed to cytokines, but the impact of inflammatory mediators on fibroblast responses in non-scarring versus scarring CLE subtypes is unclear. Here, we examined responses to cytokines in dermal fibroblasts from non-lesional skin of 22 SLE patients with CLE and 34 healthy controls. Notably, inflammatory cytokine responses were exaggerated in SLE fibroblasts compared to healthy controls. In lesional CLE biopsies, these same inflammatory profiles were reflected in single cell RNA sequencing of SFRP2+ and inflammatory fibroblast subsets, and TGF-β was identified as a critical upstream regulator for inflammatory fibroblasts in scarring discoid lupus lesions. In vitro cytokine stimulation of non-lesional fibroblasts from patients who scar from CLE identified an upregulation of collagens, particularly in response to TGF-β, whereas inflammatory pathways were more prominent in non-scarring patients. Our study revealed that SLE fibroblasts are poised to hyper-respond to inflammation, with differential responses among scarring versus non-scarring disease, providing a potential skin-specific target for mitigating damage.
Suzanne K. Shoffner-Beck, Lisa Abernathy-Close, Stephanie Lazar, Feiyang Ma, Mehrnaz Gharaee-Kermani, Amy Hurst, Craig Dobry, Deepika Pandian, Rachael Wasikowski, Amanda Victory, Kelly Arnold, Johann E. Gudjonsson, Lam C. Tsoi, J. Michelle Kahlenberg
Suppressor of Fused (SUFU) is widely regarded as a key negative regulator of the Sonic Hedgehog (SHH) morphogenic pathway and a known tumor suppressor of medulloblastoma (MB). However, we report here that SUFU expression was markedly increased in 75% of specimens compiled in a tissue array comprising 49 unstratified MBs. The SUFU and GLI1 expression levels in this MB array showed strong positive correlation, which was also identified in a large public dataset containing 736 MBs. We further report that increasing Sufu gene dosage in mice caused pre-axial polydactyly, which was associated with the expansion of the Gli3 domain in the anterior limb bud and heightened Shh signaling responses during embryonic development. Increasing Sufu gene dosage also led to accelerated cerebellar development and, when combined with ablation of the Shh receptor encoded by Patched1 (Ptch1), promoted medulloblastoma tumorigenesis. These data reveal multi-faceted roles of SUFU in promoting MB tumorigenesis by enhancing SHH signaling. This revelation clarifies potentially counter-intuitive clinical observation of high SUFU expression in MBs and may pave way for novel strategies to reduce or reverse MB progression.
Boang Han, Yu Wang, Shen Yue, Yun-hao Zhang, Lun Kuang, Bin-bin Gao, Yue Wang, Ziyu Zhang, Xiaohong Pu, Xin-fa Wang, Chi-chung Hui, Ting-ting Yu, Chen Liu, Steven Y. Cheng
Neuroblastoma is an aggressive pediatric cancer with a high rate of metastasis to the bone marrow. Despite intensive treatments including high-dose chemotherapy, the overall survival rate for children with metastatic neuroblastoma remains dismal. Understanding the cellular and molecular mechanisms of the metastatic tumor microenvironment is crucial for developing new therapies and improving clinical outcomes. Here, we used single-cell RNA-sequencing to characterize immune and tumor cell alterations in neuroblastoma bone marrow metastases by comparative analysis with patients without metastases. Our results revealed remodeling of the immune cell populations and reprogramming of gene expression profiles in the metastatic niche. In particular, within the bone marrow metastatic niche we observed the enrichment of immune cells, including tumor-associated neutrophils, macrophages, and exhausted T cells, as well as an increased number of regulatory T cells and a decreased number of B cells. Furthermore, we highlighted cell communication between tumor cells and immune cell populations, and identified prognostic markers in malignant cells that are associated with worse clinical outcomes in three independent neuroblastoma cohorts. Our results provide insights into the cellular, compositional and transcriptional shifts underlying neuroblastoma bone marrow metastases contributing to the development of new therapeutic strategies.
Shenglin Mei, Adele M. Alchahin, Bethel Tesfai Embaie, Ioana Maria Gavriliuc, Bronte Manouk Verhoeven, Ting Zhao, Xiangyun Li, Nathan Elias Jeffries, Adena Pepich, Hirak Sarkar, Thale Kristin Olsen, Malin Wickström, Jakob Stenman, Oscar Reina-Bedoya, Peter V. Kharchenko, Philip J. Saylor, John Inge Johnsen, David B. Sykes, Per Kogner, Ninib Baryawno
Despite effective antibiotic therapy, brain destructive inflammation often cannot be avoided in pneumococcal meningitis. The causative signals are mediated predominantly through TLR recruited myeloid differentiation primary response adaptor (MyD) 88 as indicated by a dramatic pneumococcal meningitis phenotype of Myd88-/- mice. Because lipoproteins and ssRNA are crucial for recognition of Gram-positive bacteria such as Streptococcus pneumoniae by the host immune system, we comparatively analyzed the disease courses of Myd88-/- and Tlr2/13-/- mice. Their phenotype resemblance indicated TLR2 and -13 as master sensors of Streptococcus pneumoniae in the cerebrospinal fluid. The neutralizing anti-TLR2 antibody (T2.5) and chloroquine (CQ) – the latter applied here as an inhibitor for murine TLR13 and its human orthologue TLR8 – abrogated activation of murine and human primary immune cells exposed to antibiotic-treated Streptococcus pneumoniae. The inhibitory effect of the T2.5/CQ cocktail was stronger than that of dexamethasone, the current standard adjunctive drug for pneumococcal meningitis. Accordingly, TLR2/13 blockade concomitant with ceftriaxone application significantly improved the clinical course of pneumococcal meningitis compared to treatment with ceftriaxone alone or in combination with dexamethasone. Our study implicates the importance of murine TLR13 and human TLR8, besides TLR2, in pneumococcal meningitis pathology, and suggests their blockade as a promising antibiotic therapy adjunct.
Susanne Dyckhoff-Shen, Ilias Masouris, Heba Islam, Sven Hammerschmidt, Barbara Angele, Veena Marathe, Jan Buer, Stefanie Völk, Hans-Walter Pfister, Matthias Klein, Uwe Koedel, Carsten J. Kirschning
Connexin43 (Cx43) is the most abundant gap junction protein present in the mesenchymal lineage. In mature adipocytes, Cx43 mediates white adipose tissue (WAT) “beiging” in response to cold exposure and maintains the mitochondrial integrity of brown adipose tissue (BAT). We found that genetic deletion of Gja1 (Cx43 gene) in cells that give rise to chondro-osteogenic and adipogenic precursors driven by the Dermo1/Twist2 promoter led to lower body adiposity and partial protection against the weight gain and metabolic syndrome induced by a high fat diet (HFD) in both sexes. These protective effects from obesogenic diet were related to increased locomotion, fuel utilization, energy expenditure, non-shivering thermogenesis, and better glucose tolerance in conditionally Gja1 ablated mice. Accordingly, Gja1 mutant mice exhibited reduced adipocyte hypertrophy, partially preserved insulin sensitivity, increased BAT lipolysis and decreased whitening under HFD. This metabolic phenotype was not reproduced with more restricted Gja1 ablation in differentiated adipocytes, suggesting that Cx43 in adipocyte progenitors or other targeted cells restrains energy expenditures and promotes fat accumulation. These results disclose an hitherto unknown action of Cx43 in adiposity, and offer a promising new pharmacologic target for improving metabolic balance in diabetes and obesity.
Seung-Yon Lee, Francesca Fontana, Toshifumi Sugatani, Ignacio Portales Castillo, Giulia Leanza, Ariella Coler-Reilly, Roberto Civitelli
Glucose homeostasis is achieved via complex interactions between the endocrine pancreas and other peripheral tissues and glucoregulatory neurocircuits in the brain that remain incompletely defined. Within the brain, neurons in the hypothalamus appear to play a particularly important role. Consistent with this notion, we report evidence that (pro)renin receptor (PRR) signaling within a subset of tyrosine hydroxylase (TH) neurons located in the hypothalamic paraventricular nucleus (PVNTH neurons) is a physiological determinant of the defended blood glucose level. Specifically, we demonstrate that PRR deletion from PVNTH neurons restores normal glucose homeostasis in mice with diet-induced obesity (DIO). Conversely, chemogenetic inhibition of PVNTH neurons mimics the deleterious effect of DIO on glucose. Combined with our finding that PRR activation inhibits PVNTH neurons, these findings suggest that in mice, (a) PVNTH neurons play a physiological role in glucose homeostasis, (b) PRR activation impairs glucose homeostasis by inhibiting these neurons, and (c) this mechanism plays a causal role in obesity-associated metabolic impairment.
Shiyue Pan, Lucas A.C. Souza, Caleb J. Worker, Miriam E. Reyes Mendez, Ariana Julia B. Gayban, Silvana G. Cooper, Alfredo Sanchez Solano, Richard N. Bergman, Darko Stefanovski, Gregory J. Morton, Michael W. Schwartz, Yumei Feng Earley
The gut and local esophageal microbiome progressively shift from healthy commensal bacteria to inflammatory-linked pathogenic bacteria in patients with gastroesophageal reflux disease, Barrett’s esophagus and esophageal adenocarcinoma (EAC). However, mechanisms by which microbial communities and metabolites contribute to reflux-driven EAC remain incompletely understood and challenging to target. Herein, we utilized a rat reflux-induced EAC model to investigate targeting the gut microbiome-esophageal metabolome axis with cranberry proanthocyanidins (C-PAC) to inhibit EAC progression. Sprague Dawley rats, with or without reflux-induction received water or C-PAC ad libitum (700 µg/rat/day) for 25 or 40 weeks. C-PAC exerted prebiotic activity abrogating reflux-induced dysbiosis, and mitigating bile acid metabolism and transport, culminating in significant inhibition of EAC through TLR/NF-κB/TP53 signaling cascades. At the species level, C-PAC mitigated reflux-induced pathogenic bacteria (Streptococcus parasanguinis, Escherichia coli, and Proteus mirabilis). C-PAC specifically reversed reflux-induced bacterial, inflammatory and immune-implicated proteins and genes including Ccl4, Cd14, Crp, Cxcl1, Il6, Il1β, Lbp, Lcn2, Myd88, Nfkb1, Tlr2, and Tlr4 aligning with changes in human EAC progression, as confirmed through public databases. C-PAC is a safe promising dietary constituent that may be utilized alone or potentially as an adjuvant to current therapies to prevent EAC progression through ameliorating reflux-induced dysbiosis, inflammation and cellular damage.
Katherine M. Weh, Connor L. Howard, Yun Zhang, Bridget A. Tripp, Jennifer L. Clarke, Amy B. Howell, Joel H. Rubenstein, Julian A. Abrams, Maria Westerhoff, Laura A. Kresty
Severe dysfunction in cardiac muscle intracellular Ca2+ handling is a common pathway underlying heart failure. Here we used an inducible genetic model of severe Ca2+ cycling dysfunction by the targeted temporal gene ablation of the cardiac Ca2+ ATPase, SERCA2, in otherwise normal adult mice. In this model, in vivo heart performance is surprisingly little affected initially, even though Serca2a protein is markedly reduced. The mechanism underlying the sustained in vivo heart performance in the weeks prior to complete heart pump failure and death is not clear and important to understand. Studies were primarily focused on understanding how in vivo diastolic function could be relatively normal under conditions of marked Serca2a deficiency. Interestingly, data show increased cardiac TnI serine 23/24 phosphorylation content in hearts upon Serca2a ablation in vivo. We report that in hearts isolated from the Serca2 deficient mice retained near normal heart pump functional responses to ß-adrenergic stimulation. Unexpectedly, using genetic complementation models, in concert with inducible Serca2 ablation, data show that Serca2a deficient hearts that also lacked the central ß-adrenergic signaling-dependent Serca2a negative regulator, phospholamban (PLN), had severe diastolic dysfunction that could still be corrected by ß-adrenergic stimulation. Notably, integrating a serine 23/24 to alanine PKA-refractory sarcomere incorporated cardiac troponin I molecular switch complex in mice deficient in Serca2 showed blunting of ß-adrenergic stimulation-mediated enhanced diastolic heart performance. Taken together, these data provide new evidence of a compensatory regulatory role of the myofilaments as a critical physiological bridging mechanism to aid in preserving heart diastolic performance in failing hearts with severe Ca2+ handling deficits.
Frazer I. Heinis, Brian R. Thompson, Rishi Gulati, Matthew Wheelwright, Joseph M. Metzger
The human adult immune system maintains normal T-cell counts and compensates for T-cell loss over lifetime mainly through peripheral homeostatic proliferation after the ability of the thymus to generate new T cells has rapidly declined at adolescence. This process is mainly driven by STAT5-activating cytokines, most importantly IL-7, and is very effective in maintaining a large naïve CD4 T cell compartment into older age. Here, we describe that naïve CD4 T cells undergo adaptations to optimize IL-7 responses by upregulating the guanine-nucleotide exchange factor PREX1 at older age. PREX1 promotes nuclear translocation of phosphorylated STAT5, thereby supporting homeostatic proliferation in response to IL-7. Through the same mechanism, increased expression of PREX1 also biases naïve cells to differentiate into effector T cells. These findings are consistent with the concept that primarily beneficial adaptations during aging, i.e., improved homeostasis, account for unfavorable functions of the aged immune system, in this case biased differentiation.
Huimin Zhang, Hirohisa Okuyama, Abhinav Jain, Rohit R. Jadhav, Bowen Wu, Ines Sturmlechner, Jose Morales, Shozo Ohtsuki, Cornelia M. Weyand, Jörg J. Goronzy
Inappropriate immune activity is key in the pathogenesis of multiple diseases and is typically driven by excess inflammation and/or autoimmunity. IL-1 is often the effector due to its powerful role in both innate and adaptive immunity, and thus is tightly controlled at multiple levels. IL-1R2 antagonises IL-1, but effects of losing this regulation is unknown. We find IL-1R2 resolves inflammation by rapidly scavenging free IL-1. Specific IL-1R2 loss in germinal centre (GC) T follicular regulatory (Tfr) cells increases the GC response after a first, but not booster, immunisation, with more T follicular helper (Tfh) cells, GC B cells and antigen-specific antibodies, which is reversed upon IL-1 blockade. However, IL-1 signalling is not obligate for GC reactions, as wildtype and Il1r1–/– mice show equivalent phenotypes, suggesting GC IL-1 is normally restrained by IL-1R2. Fascinatingly, germline Il1r2–/– mice do not show this phenotype, but conditional Il1r2 deletion in adulthood recapitulates it, implying compensation during development counteracts IL-1R2 loss. Finally, patients with ulcerative colitis or Crohn’s disease have lower serum IL-1R2. Together, we show that IL-1R2 controls important aspects of innate and adaptive immunity, and that IL-1R2 level may contribute to human disease propensity and/or progression.
Katerina Pyrillou, Melanie Humphry, Lauren A. Kitt, Amanda Rodgers, Meritxell Nus, Martin R. Bennett, Kenneth G.C. Smith, Paul A. Lyons, Ziad Mallat, Murray C.H. Clarke
Atopic dermatitis (AD) is a persistent skin disease typified by symptoms of dry skin and recurrent eczema. AD patients are at heightened risk for Staphylococcus aureus (S. aureus) infection. Group 2 innate lymphoid cells (ILC2s) are mainly activated by epithelial cell-derived cytokines IL-33 and involved in the pathogenesis of AD. However, little is known about the effect of skin delipidization on the epithelial cell-derived cytokines and dermal ILC2s in AD. In our study, we investigated the mechanism by which S. aureus infection modulates and exacerbates the pathogenesis of dry skin, leading to type 2 inflammation in the context of innate immunity. In vivo, we found that S. aureus infection aggravated delipidization-induced dermal IL-33 release and dermal ILC2 accumulation, which exacerbated skin inflammation. We also noticed that Il33f/fK14cre mice and Tlr2–/– mice exhibited attenuated skin inflammation. In vitro, treatment with necroptosis inhibitors reduced IL-33 release from S. aureus-infected keratinocytes. Mechanistically, we observed an increase in the necroptosis-associated kinases, MLKL and RIPK3, in S. aureus-infected mice, indicating that IL-33 release was associated with necroptotic cell death responses. Our results reveal that S. aureus infection-elicited keratinocyte necroptosis contributes to IL-33-mediated type 2 inflammation, which exacerbates the pathogenesis of dry skin.
Chia-Hui Luo, Alan Chuan-Ying Lai, Chun-Chou Tsai, Wei-Yu Chen, Yu-Shan Chang, Ethan Ja-Chen Chung, Ya-Jen Chang
Pattern-Recognition Receptor responses are profoundly attenuated before the third trimester of gestation, in the relatively low oxygen human fetal environment. However, the mechanisms regulating these responses are uncharacterized. Herein, genome-wide transcription and functional metabolic experiments in primary neonatal monocytes linked the negative mTOR regulator DDIT4L to metabolic stress, cellular bioenergetics and innate immune activity. Using genetically engineered monocytic U937 cells, we confirmed that DDIT4L overexpression altered mitochondrial dynamics, suppressing their activity, and blunted LPS-induced cytokine responses. We also showed that monocyte mitochondrial function is more restrictive in earlier gestation, resembling the phenotype of DDIT4L-overexpressing U937 cells. Gene expression analyses in neonatal granulocytes, and lung macrophages in preterm infants confirmed upregulation of the DDIT4L gene in the early postnatal period, and also suggested a potential protective role against inflammation-associated chronic neonatal lung disease. Together, these data show that DDIT4L regulates mitochondrial activity and provide the first direct evidence for its potential role regulating innate immune activity in myeloid cells during development.
Christina Michalski, Claire Cheung, Ju Hee Oh, Emma Ackermann, Constantin R. Popescu, Anne-Sophie Archambault, Martin A. Prusinkiewicz, Rachel Da Silva, Abdelilah Majdoubi, Marina Viñeta Paramo, Rui Yang Xu, Frederic Reicherz, Annette E. Patterson, Liam Golding, Ashish A. Sharma, Chinten J. Lim, Paul C. Orban, Ramon I. Klein Geltink, Pascal M. Lavoie
Cauterization of the root of the left coronary artery (LCA) in the neonatal heart at postnatal day 1 (P1) resulted in large reproducible lesions of the left ventricle (LV), and an attendant marked adaptive response in the right ventricle (RV). The response of both chambers to LV myocardial infarction involved enhanced cardiomyocyte (CM) division and binucleation, as well as LV re-vascularization, leading to restored heart function within 7 days post-surgery (7 dps). By contrast, infarction of P3 mice resulted in cardiac scarring without a significant regenerative and adaptive response of the LV and the RV leading to subsequent heart failure and death within 7 dps. The prominent RV myocyte expansion in P1 mice involved an acute increase in pulmonary arterial pressure and a unique gene regulatory response, leading to an increase in RV mass and preserved heart function. Thus, distinct adaptive mechanisms in the RV, such as CM proliferation and RV expansion, enable marked cardiac regeneration of the infarcted LV at P1 and full functional recovery.
Tianyuan Hu, Mona Malek Mohammadi, Fabian Ebach, Michael Hesse, Michael I. Kotlikoff, Bernd K. Fleischmann
Dedifferentiation or phenotype switching refers to the transition from a proliferative to an invasive cellular state. We previously identified a 122-gene epigenetic gene signature that classifies primary melanomas as low- versus high-risk (denoted as Epgn1 or Epgn3). We found that the transcriptomes of the Epgn1 low-risk and Epgn3 high-risk cells are similar to the proliferative and invasive cellular states, respectively. These signatures were further validated in melanoma tumor samples. Examination of the chromatin landscape revealed differential H3K27 acetylation in the Epgn1 low-risk versus Epgn3 high-risk cell lines that corroborated with a differential super-enhancer and enhancer landscape. Melanocytic lineage genes (MITF, its targets and regulators) were associated with super-enhancers in the Epgn1 low-risk state whereas invasiveness genes were linked with Epgn3 high-risk status. We identified ITGA3 gene as marked by a super-enhancer element in the Epgn3 invasive cells. Silencing of ITGA3 enhanced invasiveness in both in vitro and in vivo systems suggesting it as a negative regulator of invasion. In conclusion, we define chromatin landscape changes associated with Epgn1/3 and phenotype switching during early steps of melanoma progression that regulate transcriptional reprogramming. This super-enhancer and enhancer-driven epigenetic regulatory mechanism resulting in major changes in the transcriptome could be important in future therapeutic targeting efforts.
Karen Mendelson, Tiphaine C. Martin, Christie B. Nguyen, Min Hsu, Jia Xu, Claudia C.V. Lang, Reinhard Dummer, Yvonne Saenger, Jane L. Messina, Vernon K. Sondak, Garrett Desman, Dan Hasson, Emily Bernstein, Ramon E. Parsons, Julide Tok Celebi
Acute bacterial orchitis (AO) is a prevalent cause of intra-scrotal inflammation, often resulting in sub- or infertility. A frequent cause eliciting AO is uropathogenic Escherichia coli (UPEC), a gram negative pathovar, characterized by the expression of various iron acquisition systems to survive in a low-iron environment. On the host side, iron is tightly regulated by iron regulatory proteins (IRP) 1 and 2 and these factors are reported to play a role in testicular and immune cell function, however, their precise role remains unclear. Here, we showed in a mouse model of UPEC-induced orchitis that the absence of IRP1 results in reduced immune response and testicular damage. Compared to infected wild-type (WT)-mice, testis of UPEC-infected Irp1–/– mice showed impaired ERK signaling. Conversely, IRP2 deletion led to a stronger inflammatory response. Notably, differences in immune cell infiltrations were observed among the different genotypes. In contrast to WT and Irp2–/– mice, no increase in monocytes and neutrophils was detected in testis of Irp1–/– mice upon UPEC-infection. Interestingly, in Irp1–/– UPEC-infected testis, we observed an increase in a subpopulation of macrophages (F4/80+ CD206+) associated with anti-inflammatory and wound-healing activities compared to WT. These findings suggest that IRP1 deletion may protect against UPEC-induced inflammation by modulating ERK signaling and dampening the immune response.
Niraj Ghatpande, Aileen Harrer, Bar Azoulay-Botzer, Noga Guttmann-Raviv, Sudhanshu Bhushan, Andreas Meinhardt, Esther G. Meyron-Holtz
Geleophysic Dysplasia-1 (GD1) is an autosomal recessive disorder caused by ADAMTSL2 variants. It is characterized by distinctive facial features, limited joint mobility, short stature with brachydactyly, and the potential for life-threatening cardiovascular and respiratory complications. The clinical spectrum spans from perinatal lethality to milder phenotypes in adult survivors, manifesting a clinical heterogeneity. The Adamtsl2–/– mouse model dies perinatally and hinders further functional investigation. In this study, we developed and characterized cellular and mouse models, which were designed to replicate the genetic profile of a patient who is compound heterozygous for two ADAMTSL2 variants, namely p.R61H and p.A165T. The impairment of ADAMTSL2 secretion was observed in both variants, but notably, p.A165T exhibited a more severe impact. We conducted a thorough analysis of mice carrying different allelic combinations, including knockout, p.R61H, and p.A165T variants. This examination revealed a wide spectrum of phenotypic severity, spanning from lethality in knockout homozygotes to mild growth impairment observed in adult p.R61H homozygotes. While they survived, the homozygous and hemizygous p.A165T mice displayed severe respiratory and cardiac dysfunction. The respiratory dysfunction mainly affects the expiration phase without significant fibrosis in the lungs. Evidence of microscopic post-obstructive pneumonia was found in some hemizygous and homozygous p.A165T. Echocardiograms and MRI studies revealed a significant systolic dysfunction, accompanied by a reduction in the size of the aortic root. Histological examinations further confirmed the presence of hypertrophic cardiomyopathy with myocyte hypertrophy. In addition, evidence of elevated proteoglycan staining in the myocardium, chondroid metaplasia, along with patchy mild interstitial fibrosis within the myocardium was seen in hemizygous and homozygous p.A165T. In conclusion, our study revealed a significant correlation between the degree of impaired ADAMTSL2 secretion and the severity of the observed phenotype in GD1. The surviving mouse models we developed have provided valuable insights into the pathogenesis of GD and hold promise as valuable tools for informing and guiding future therapeutic interventions aimed at managing this disorder effectively.
Vladimir Camarena, Monique M. Williams, Alejo A. Morales, Mohammad F. Zafeer, Okan V. Kilic, Ali Kamiar, Clemer Abad, Monica A. Rasmussen, Laurence M. Briski, LéShon Peart, Guney Bademci, Deborah S. Barbouth, Sarah Smithson, Gaofeng Wang, Lina A. Shehadeh, Katherina Walz, Mustafa Tekin