In this issue, Lu et al. show that smooth muscle cell–derived resident vascular adventitial progenitor cells adopt a myofibroblast phenotype in response to vascular injury and play a dominant role in vascular fibrosis. The cover image shows cells of AdvSca1-SM progenitor lineage (green; immunofluorescence staining) closely embedded within a collagen-rich extracellular matrix (red; second harmonic generation imaging) in the adventitia of angiotensin II–treated mouse aortic tissue.
A possible etiological link between the onset of endemic pemphigus in Tunisia and bites of Phlebotomus papatasi, the vector of zoonotic cutaneous leishmaniasis, has been previously suggested. We hypothesized that the immunodominant P. papatasi salivary protein PpSP32 binds to desmogleins 1 and 3 (Dsg1 and Dsg3), triggering loss of tolerance to these pemphigus target autoantigens. Here, we show using far-Western blot that the recombinant PpSP32 protein (rPpSP32) binds to epidermal proteins with a MW of approximately 170 kDa. Coimmunoprecipitation revealed the interaction of rPpSP32 with either Dsg1 or Dsg3. A specific interaction between PpSP32 and Dsg1 and Dsg3 was further demonstrated by ELISA assays. Finally, mice immunized with rPpSP32 twice per week exhibited significantly increased levels of anti-Dsg1 and -Dsg3 antibodies from day 75 to 120. Such antibodies were specific for Dsg1 and Dsg3 and were not the result of cross-reactivity to PpSP32. In this study, we demonstrated for the first time to our knowledge a specific binding between PpSP32 and Dsg1 and Dsg3, which might underlie the triggering of anti-Dsg antibodies in patients exposed to sand fly bites. We also confirmed the development of specific anti-Dsg1 and -Dsg3 antibodies in vivo after PpSP32 immunization in mice. Collectively, our results provide evidence that environmental factors, such as the exposure to P. papatasi bites, can trigger the development of autoimmune antibodies.
Soumaya Marzouki, Ines Zaraa, Maha Abdeladhim, Chaouki Benabdesselem, Fabiano Oliveira, Shaden Kamhawi, Mourad Mokni, Hechmi Louzir, Jesus G. Valenzuela, Melika Ben Ahmed
Pituitary developmental defects lead to partial or complete hormone deficiency and significant health problems. The majority of cases are sporadic and of unknown cause. We screened 28 patients with pituitary stalk interruption syndrome for mutations in the FAT/DCHS family of protocadherins that have high functional redundancy. We identified 7 variants, 4 of which are putatively damaging, in FAT2 and DCHS2 in 6 patients with pituitary developmental defects recruited through a cohort of patients with mostly ectopic posterior pituitary gland and/or pituitary stalk interruption. All patients had growth hormone deficiency, and 2 presented with multiple hormone deficiencies and small glands. FAT2 and DCHS2 were strongly expressed in the mesenchyme surrounding the normal developing human pituitary. We analyzed Dchs2–/– mouse mutants and identified anterior pituitary hypoplasia and partially penetrant infundibular defects. Overlapping infundibular abnormalities and distinct anterior pituitary morphogenesis defects were observed in Fat4–/– and Dchs1–/– mouse mutants, but all animal models displayed normal commitment to anterior pituitary cell types. Together our data implicate FAT/DCHS protocadherins in normal hypothalamic-pituitary development and identify FAT2 and DCHS2 as candidates underlying pituitary gland developmental defects such as ectopic pituitary gland and/or pituitary stalk interruption.
Emily J. Lodge, Paraskevi Xekouki, Tatiane S. Silva, Cristiane Kochi, Carlos A. Longui, Fabio R. Faucz, Alice Santambrogio, James L. Mills, Nathan Pankratz, John Lane, Dominika Sosnowska, Tina Hodgson, Amanda L. Patist, Philippa Francis-West, Françoise Helmbacher, Constantine A. Stratakis, Cynthia L. Andoniadou
Ongoing societal changes in views on the medical and recreational roles of cannabis increased the use of concentrated plant extracts with a Δ9-tetrahydrocannabinol (THC) content of more than 90%. Even though prenatal THC exposure is widely considered adverse for neuronal development, equivalent experimental data for young age cohorts are largely lacking. Here, we administered plant-derived THC (1 or 5 mg/kg) to mice daily during P5–P16 and P5–P35 and monitored its effects on hippocampal neuronal survival and specification by high-resolution imaging and iTRAQ proteomics, respectively. We found that THC indiscriminately affects pyramidal cells and both cannabinoid receptor 1+ (CB1R)+ and CB1R– interneurons by P16. THC particularly disrupted the expression of mitochondrial proteins (complexes I–IV), a change that had persisted even 4 months after the end of drug exposure. This was reflected by a THC-induced loss of membrane integrity occluding mitochondrial respiration and could be partially or completely rescued by pH stabilization, antioxidants, bypassed glycolysis, and targeting either mitochondrial soluble adenylyl cyclase or the mitochondrial voltage-dependent anion channel. Overall, THC exposure during infancy induces significant and long-lasting reorganization of neuronal circuits through mechanisms that, in large part, render cellular bioenergetics insufficient to sustain key developmental processes in otherwise healthy neurons.
Johannes Beiersdorf, Zsofia Hevesi, Daniela Calvigioni, Jakob Pyszkowski, Roman Romanov, Edit Szodorai, Gert Lubec, Sally Shirran, Catherine H. Botting, Siegfried Kasper, Geoffrey W. Guy, Roy Gray, Vincenzo Di Marzo, Tibor Harkany, Erik Keimpema
The pathophysiology underlying spiral ganglion cell defect–induced deafness remains elusive. Using the whole exome sequencing approach, in combination with functional assays and a mouse disease model, we identified the potentially novel deafness-causative MAP1B gene encoding a highly conserved microtubule-associated protein. Three novel heterozygous MAP1B mutations (c.4198A>G, p.1400S>G; c.2768T>C, p.923I>T; c.5512T>C, p.1838F>L) were cosegregated with autosomal dominant inheritance of nonsyndromic sensorineural hearing loss in 3 unrelated Chinese families. Here, we show that MAP1B is highly expressed in the spiral ganglion neurons in the mouse cochlea. Using otic sensory neuron–like cells, generated by pluripotent stem cells from patients carrying the MAP1B mutation and control subject, we demonstrated that the p.1400S>G mutation caused the reduced levels and deficient phosphorylation of MAP1B, which are involved in the microtubule stability and dynamics. Strikingly, otic sensory neuron–like cells exhibited disturbed dynamics of microtubules, axonal elongation, and defects in electrophysiological properties. Dysfunctions of these derived otic sensory neuron–like cells were rescued by genetically correcting MAP1B mutation using CRISPR/Cas9 technology. Involvement of MAP1B in hearing was confirmed by audiometric evaluation of Map1b heterozygous KO mice. These mutant mice displayed late-onset progressive sensorineural hearing loss that was more pronounced in the high frequencies. The spiral ganglion neurons isolated from Map1b mutant mice exhibited the deficient phosphorylation and disturbed dynamics of microtubules. Map1b deficiency yielded defects in the morphology and electrophysiology of spiral ganglion neurons, but it did not affect the morphologies of cochlea in mice. Therefore, our data demonstrate that dysfunctions of spiral ganglion neurons induced by MAP1B deficiency caused hearing loss.
Limei Cui, Jing Zheng, Qiong Zhao, Jia-Rong Chen, Hanqing Liu, Guanghua Peng, Yue Wu, Chao Chen, Qiufen He, Haosong Shi, Shankai Yin, Rick A. Friedman, Ye Chen, Min-Xin Guan
Understanding the distinct pathogenic mechanisms that culminate in allograft fibrosis and chronic graft failure is key in improving outcomes after solid organ transplantation. Here, we describe an F1 → parent orthotopic lung transplant model of restrictive allograft syndrome (RAS), a particularly fulminant form of chronic lung allograft dysfunction (CLAD), and identify a requisite pathogenic role for humoral immune responses in development of RAS. B6D2F1/J (H2-b/d) donor lungs transplanted into the parent C57BL/6J (H2-b) recipients demonstrated a spectrum of histopathologic changes, ranging from lymphocytic infiltration, fibrinous exudates, and endothelialitis to peribronchial and pleuroparenchymal fibrosis, similar to those noted in the human RAS lungs. Gene expression profiling revealed differential humoral immune cell activation as a key feature of the RAS murine model, with significant B cell and plasma cell infiltration noted in the RAS lung allografts. B6D2F1/J lung allografts transplanted into μMt–/– (mature B cell deficient) or activation-induced cytidine deaminase (AID)/secretory μ-chain (μs) double-KO (AID−/−μs−/−) C57BL/6J mice demonstrated significantly decreased allograft fibrosis, indicating a key role for antibody secretion by B cells in mediating RAS pathology. Our study suggests that skewing of immune responses determines the diverse allograft remodeling patterns and highlights the need to develop targeted therapies for specific CLAD phenotypes.
Keizo Misumi, David S. Wheeler, Yoshiro Aoki, Michael P. Combs, Russell R. Braeuer, Ryuji Higashikubo, Wenjun Li, Daniel Kreisel, Ragini Vittal, Jeffrey Myers, Amir Lagstein, Natalie M. Walker, Carol F. Farver, Vibha N. Lama
Atrial fibrillation (AF) commonly occurs after surgery and is associated with atrial remodeling. TRPV4 is functionally expressed in the heart, and its activation affects cardiac structure and functions. We hypothesized that TRPV4 blockade alleviates atrial remodeling and reduces AF induction in sterile pericarditis (SP) rats. TRPV4 antagonist GSK2193874 or vehicle was orally administered 1 day before pericardiotomy. AF susceptibility and atrial function were assessed using in vivo electrophysiology, ex vivo optical mapping, patch clamp, and molecular biology on day 3 after surgery. TRPV4 expression increased in the atria of SP rats and patients with AF. GSK2193874 significantly reduced AF vulnerability in vivo and the frequency of atrial ectopy and AF with a reentrant pattern ex vivo. Mechanistically, GSK2193874 reversed the abnormal action potential duration (APD) prolongation in atrial myocytes through the regulation of voltage-gated K+ currents (IK); reduced the activation of atrial fibroblasts by inhibiting P38, AKT, and STAT3 pathways; and alleviated the infiltration of immune cells. Our results reveal that TRPV4 blockade prevented abnormal changes in atrial myocyte electrophysiology and ameliorated atrial fibrosis and inflammation in SP rats; therefore, it might be a promising strategy to treat AF, particularly postoperative AF.
Jie Liao, Qiongfeng Wu, Cheng Qian, Ning Zhao, Zhaoyang Zhao, Kai Lu, Shaoshao Zhang, Qian Dong, Lei Chen, Qince Li, Yimei Du
Loss of functional small bowel surface area following surgical resection for disorders such as Crohn’s disease, intestinal ischemic injury, radiation enteritis, and in children, necrotizing enterocolitis, atresia, and gastroschisis, may result in short bowel syndrome, with attendant high morbidity, mortality, and health care costs in the United States. Following resection, the remaining small bowel epithelium mounts an adaptive response, resulting in increased crypt cell proliferation, increased villus height, increased crypt depth, and enhanced nutrient and electrolyte absorption. Although these morphologic and functional changes are well described in animal models, the adaptive response in humans is less well understood. Clinically the response is unpredictable and often inadequate. Here we address the hypotheses that human intestinal stem cell populations are expanded and that the stem cell niche is regulated following massive gut resection in short bowel syndrome (SBS). We use intestinal enteroid cultures from patients with SBS to show that the magnitude and phenotype of the adaptive stem cell response are both regulated by stromal niche cells, including intestinal subepithelial myofibroblasts, which are activated by intestinal resection to enhance epithelial stem and proliferative cell responses. Our data suggest that myofibroblast regulation of bone morphogenetic protein signaling pathways plays a role in the gut adaptive response after resection.
Vered A. Gazit, Elzbieta A. Swietlicki, Miranda U. Liang, Adam Surti, Raechel McDaniel, Mackenzie Geisman, David M. Alvarado, Matthew A. Ciorba, Grant Bochicchio, Obeid Ilahi, John Kirby, William J. Symons, Nicholas O. Davidson, Marc S. Levin, Deborah C. Rubin
Resident vascular adventitial SCA1+ progenitor (AdvSca1) cells are essential in vascular development and injury. However, the heterogeneity of AdvSca1 cells presents a unique challenge in understanding signaling pathways orchestrating their behavior in homeostasis and injury responses. Using smooth muscle cell (SMC) lineage-tracing models, we identified a subpopulation of AdvSca1 cells (AdvSca1-SM) originating from mature SMCs that undergo reprogramming in situ and exhibit a multipotent phenotype. Here we employed lineage tracing and RNA-sequencing to define the signaling pathways regulating SMC-to-AdvSca1-SM cell reprogramming and AdvSca1-SM progenitor cell phenotype. Unbiased hierarchical clustering revealed that genes related to hedgehog/WNT/beta-catenin signaling were significantly enriched in AdvSca1-SM cells, emphasizing the importance of this signaling axis in the reprogramming event. Leveraging AdvSca1-SM–specific expression of GLI-Kruppel family member GLI1 (Gli1), we generated Gli1-CreERT2-ROSA26-YFP reporter mice to selectively track AdvSca1-SM cells. We demonstrated that physiologically relevant vascular injury or AdvSca1-SM cell–specific Kruppel-like factor 4 (Klf4) depletion facilitated the proliferation and differentiation of AdvSca1-SM cells to a profibrotic myofibroblast phenotype rather than macrophages. Surprisingly, AdvSca1-SM cells selectively contributed to adventitial remodeling and fibrosis but little to neointima formation. Together, these findings strongly support therapeutics aimed at preserving the AdvSca1-SM cell phenotype as a viable antifibrotic approach.
Sizhao Lu, Austin J. Jolly, Keith A. Strand, Allison M. Dubner, Marie F. Mutryn, Karen S. Moulton, Raphael A. Nemenoff, Mark W. Majesky, Mary C.M. Weiser-Evans
Caspase-8 (CASP8) is one of the most frequently mutated genes in head and neck squamous carcinomas (HNSCCs), and CASP8 mutations are associated with poor survival. The distribution of these mutations in HNSCCs suggests that they are likely to be inactivating. Inhibition of CASP8 has been reported to sensitize cancer cells to necroptosis, a regulated cell death mechanism. Here, we show that knockdown of CASP8 renders HNSCCs susceptible to necroptosis by a second mitochondria-derived activator of caspase (SMAC) mimetic, birinapant, in combination with pan-caspase inhibitors Z-VAD-FMK or emricasan and radiation. In a syngeneic mouse model of oral cancer, birinapant, particularly when combined with radiation, delayed tumor growth and enhanced survival under CASP8 loss. Exploration of molecular underpinnings of necroptosis sensitivity confirmed that the level of functional receptor-interacting serine/threonine protein kinase 3 (RIP3) determines susceptibility to this mode of death. Although an in vitro screen revealed that low RIP3 levels rendered many HNSCC cell lines resistant to necroptosis, patient tumors maintained RIP3 expression and should therefore remain sensitive. Collectively, these results suggest that targeting the necroptosis pathway with SMAC mimetics, especially in combination with radiation, may be relevant therapeutically in HNSCC with compromised CASP8 status, provided that RIP3 function is maintained.
Burak Uzunparmak, Meng Gao, Antje Lindemann, Kelly Erikson, Li Wang, Eric Lin, Steven J. Frank, Frederico O. Gleber-Netto, Mei Zhao, Heath D. Skinner, Jared Newton, Andrew G. Sikora, Jeffrey N. Myers, Curtis R. Pickering
Effective treatment for AML is challenging due to the presence of clonal heterogeneity and the evolution of polyclonal drug resistance. Here, we report that TP-0903 has potent activity against protein kinases related to STAT, AKT, and ERK signaling, as well as cell cycle regulators in biochemical and cellular assays. In vitro and in vivo, TP-0903 was active in multiple models of drug-resistant FLT3 mutant AML, including those involving the F691L gatekeeper mutation and bone marrow microenvironment–mediated factors. Furthermore, TP-0903 demonstrated preclinical activity in AML models with FLT3-ITD and common co-occurring mutations in IDH2 and NRAS genes. We also showed that TP-0903 had ex vivo activity in primary AML cells with recurrent mutations including MLL-PTD, ASXL1, SRSF2, and WT1, which are associated with poor prognosis or promote clinical resistance to AML-directed therapies. Our preclinical studies demonstrate that TP-0903 is a multikinase inhibitor with potent activity against multiple drug-resistant models of AML that will have an immediate clinical impact in a heterogeneous disease like AML.
Jae Yoon Jeon, Daelynn R. Buelow, Dominique A. Garrison, Mingshan Niu, Eric D. Eisenmann, Kevin M. Huang, Megan E. Zavorka Thomas, Robert H. Weber, Clifford J. Whatcott, Steve L. Warner, Shelley J. Orwick, Bridget Carmichael, Emily Stahl, Lindsey T. Brinton, Rosa Lapalombella, James S. Blachly, Erin Hertlein, John C. Byrd, Bhavana Bhatnagar, Sharyn D. Baker
Atherosclerosis develops preferentially in areas of the arterial system, in which blood flow is disturbed. Exposure of endothelial cells to disturbed flow has been shown to induce inflammatory signaling, including NF-κB activation, which leads to the expression of leukocyte adhesion molecules and chemokines. Here, we show that disturbed flow promotes the release of adrenomedullin from endothelial cells, which in turn activates its Gs-coupled receptor calcitonin receptor–like receptor (CALCRL). This induces antiinflammatory signaling through cAMP and PKA, and it results in reduced endothelial inflammation in vitro and in vivo. Suppression of endothelial expression of Gαs, the α subunit of the G-protein Gs; CALCRL; or adrenomedullin leads to increased disturbed flow–induced inflammatory signaling in vitro and in vivo. Furthermore, mice with induced endothelial-specific deficiency of Gαs, CALCRL, or adrenomedullin show increased atherosclerotic lesions. Our data identify an antiinflammatory signaling pathway in endothelial cells stimulated by disturbed flow and suggest activation of the endothelial adrenomedullin/CALCRL/Gs system as a promising approach to inhibit progression of atherosclerosis.
Akiko Nakayama, Julián Albarrán-Juárez, Guozheng Liang, Kenneth Anthony Roquid, András Iring, Sarah Tonack, Min Chen, Oliver J. Müller, Lee S. Weinstein, Stefan Offermanns
Cardiac ischemia is associated with arrhythmias; however, effective therapies are currently limited. The cardiac voltage-gated sodium channel α subunit (SCN5A), encoding the Nav1.5 current, plays a key role in the cardiac electrical conduction and arrhythmic risk. Here, we show that hypoxia reduces Nav1.5 through effects on a miR, miR-448. miR-448 expression is increased in ischemic cardiomyopathy. miR-448 has a conserved binding site in 3′-UTR of SCN5A. miR-448 binding to this site suppressed SCN5A expression and sodium currents. Hypoxia-induced HIF-1α and NF-κB were major transcriptional regulators for MIR448. Moreover, hypoxia relieved MIR448 transcriptional suppression by RE1 silencing transcription factor. Therefore, miR-448 inhibition reduced arrhythmic risk after myocardial infarction. Here, we show that ischemia drove miR-448 expression, reduced Nav1.5 current, and increased arrhythmic risk. Arrhythmic risk was improved by preventing Nav1.5 downregulation, suggesting a new approach to antiarrhythmic therapy.
Gyeoung-Jin Kang, An Xie, Hong Liu, Samuel C. Dudley Jr.
BACKGROUND Identifying factors conferring responses to therapy in cancer is critical to select the best treatment for patients. For immune checkpoint inhibition (ICI) therapy, mounting evidence suggests that the gut microbiome can determine patient treatment outcomes. However, the extent to which gut microbial features are applicable across different patient cohorts has not been extensively explored.METHODS We performed a meta-analysis of 4 published shotgun metagenomic studies (Ntot = 130 patients) investigating differential microbiome composition and imputed metabolic function between responders and nonresponders to ICI.RESULTS Our analysis identified both known microbial features enriched in responders, such as Faecalibacterium as the prevailing taxa, as well as additional features, including overrepresentation of Barnesiella intestinihominis and the components of vitamin B metabolism. A classifier designed to predict responders based on these features identified responders in an independent cohort of 27 patients with the area under the receiver operating characteristic curve of 0.625 (95% CI: 0.348–0.899) and was predictive of prognosis (HR = 0.35, P = 0.081).CONCLUSION These results suggest the existence of a fecal microbiome signature inherent across responders that may be exploited for diagnostic or therapeutic purposes.FUNDING This work was funded by the Knut and Alice Wallenberg Foundation, BioGaia AB, and Cancerfonden.
Angelo Limeta, Boyang Ji, Max Levin, Francesco Gatto, Jens Nielsen
Cantú syndrome (CS), caused by gain-of-function (GOF) mutations in pore-forming (Kir6.1, KCNJ8) and accessory (SUR2, ABCC9) ATP-sensitive potassium (KATP) channel subunit genes, is frequently accompanied by gastrointestinal (GI) dysmotility, and we describe 1 CS patient who required an implanted intestinal irrigation system for successful stooling. We used gene-modified mice to assess the underlying KATP channel subunits in gut smooth muscle and to model the consequences of altered KATP channels in CS gut. We show that Kir6.1/SUR2 subunits underlie smooth muscle KATP channels throughout the small intestine and colon. Knockin mice, carrying human KCNJ8 and ABCC9 CS mutations in the endogenous loci, exhibited reduced intrinsic contractility throughout the intestine, resulting in death when weaned onto solid food in the most severely affected animals. Death was avoided by weaning onto a liquid gel diet, implicating intestinal insufficiency and bowel impaction as the underlying cause, and GI transit was normalized by treatment with the KATP inhibitor glibenclamide. We thus define the molecular basis of intestinal KATP channel activity, the mechanism by which overactivity results in GI insufficiency, and a viable approach to therapy.
Nathaniel W. York, Helen Parker, Zili Xie, David Tyus, Maham Akbar Waheed, Zihan Yan, Dorothy K. Grange, Maria Sara Remedi, Sarah K. England, Hongzhen Hu, Colin G. Nichols
The habenula (Hb) is a bilateral, evolutionarily conserved epithalamic structure connecting forebrain and midbrain structures that has gained attention for its roles in depression, addiction, rewards processing, and motivation. Of its 2 major subdivisions, the medial Hb (MHb) and lateral Hb (LHb), MHb circuitry and function are poorly understood relative to those of the LHb. Prkar2a codes for cAMP-dependent protein kinase (PKA) regulatory subunit IIα (RIIα), a component of the PKA holoenzyme at the center of one of the major cell-signaling pathways conserved across systems and species. Type 2 regulatory subunits (RIIα, RIIβ) determine the subcellular localization of PKA, and unlike other PKA subunits, Prkar2a has minimal brain expression except in the MHb. We previously showed that RIIα-knockout (RIIα-KO) mice resist diet-induced obesity. In the present study, we report that RIIα-KO mice have decreased consumption of palatable, “rewarding” foods and increased motivation for voluntary exercise. Prkar2a deficiency led to decreased habenular PKA enzymatic activity and impaired dendritic localization of PKA catalytic subunits in MHb neurons. Reexpression of Prkar2a in the Hb rescued this phenotype, confirming differential roles for Prkar2a in regulating the drives for palatable foods and voluntary exercise. Our findings show that in the MHb decreased PKA signaling and dendritic PKA activity decrease motivation for palatable foods, while enhancing the motivation for exercise, a desirable combination of behaviors.
Edra London, Jason C. Wester, Michelle Bloyd, Shelby Bettencourt, Chris J. McBain, Constantine A. Stratakis
We remain largely without effective prophylactic/therapeutic interventions for COVID-19. Although many human COVID-19 clinical trials are ongoing, there remains a deficiency of supportive preclinical drug efficacy studies to help guide decisions. Here we assessed the prophylactic/therapeutic efficacy of hydroxychloroquine (HCQ), a drug of interest for COVID-19 management, in 2 animal disease models. The standard human malaria HCQ prophylaxis (6.5 mg/kg given weekly) and treatment (6.5 mg/kg given daily) did not significantly benefit clinical outcome, nor did it reduce SARS-CoV-2 replication/shedding in the upper and lower respiratory tract in the rhesus macaque disease model. Similarly, when used for prophylaxis or treatment, neither the standard human malaria dose (6.5 mg/kg) nor a high dose (50 mg/kg) of HCQ had any beneficial effect on clinical disease or SARS-CoV-2 kinetics (replication/shedding) in the Syrian hamster disease model. Results from these 2 preclinical animal models may prove helpful in guiding clinical use of HCQ for prophylaxis/treatment of COVID-19.
Kyle Rosenke, Michael A. Jarvis, Friederike Feldmann, Benjamin Schwarz, Atsushi Okumura, Jamie Lovaglio, Greg Saturday, Patrick W. Hanley, Kimberly Meade-White, Brandi N. Williamson, Frederick Hansen, Lizette Perez-Perez, Shanna Leventhal, Tsing-Lee Tang-Huau, Julie Callison, Elaine Haddock, Kaitlin A. Stromberg, Dana Scott, Graham Sewell, Catharine M. Bosio, David Hawman, Emmie de Wit, Heinz Feldmann
Proprotein convertase subtilisin/kexin type 9 (PCSK9) affects cholesterol homeostasis by targeting hepatic LDL receptor (LDLR) for lysosomal degradation. Clinically, PCSK9 inhibitors effectively reduce LDL-cholesterol (LDL-C) levels and the incidence of cardiovascular events. Because microRNAs (miRs) are integral regulators of cholesterol homeostasis, we investigated the involvement of miR-483 in regulating LDL-C metabolism. Using in silico analysis, we predicted that miR-483-5p targets the 3′-UTR of PCSK9 mRNA. In HepG2 cells, miR-483-5p targeted the PCSK9 3′-UTR, leading to decreased PCSK9 protein and mRNA expression, increased LDLR expression, and enhanced LDL-C uptake. In hyperlipidemic mice and humans, serum levels of total cholesterol and LDL-C were inversely correlated with miR-483-5p levels. In mice, hepatic miR-483 overexpression increased LDLR levels by targeting Pcsk9, with a significant reduction in plasma total cholesterol and LDL-C levels. Mechanistically, the cholesterol-lowering effect of miR-483-5p was significant in mice receiving AAV8 PCSK9-3′-UTR but not Ldlr-knockout mice or mice receiving AAV8 PCSK9-3′-UTR (ΔBS) with the miR-483-5p targeting site deleted. Thus, exogenously administered miR-483 or similarly optimized compounds have potential to ameliorate hypercholesterolemia.
Jianjie Dong, Ming He, Jie Li, Ariane Pessentheiner, Chen Wang, Jin Zhang, Yameng Sun, Wei-Ting Wang, Yuqing Zhang, Junhui Liu, Shen-Chih Wang, Po-Hsun Huang, Philip L.S.M. Gordts, Zu-Yi Yuan, Sotirios Tsimikas, John Y.J. Shyy
Alisa B. Lee-Sherick, Kristen M. Jacobsen, Curtis J. Henry, Madeline G. Huey, Rebecca E. Parker, Lauren S. Page, Amanda A. Hill, Xiaodong Wang, Stephen V. Frye, H. Shelton Earp, Craig T. Jordan, Deborah DeRyckere, Douglas K. Graham