BACKGROUND. Clinical data to support the use of bamlanivimab for the treatment of outpatients with mild to moderate coronavirus disease-19 (COVID-19) is needed. METHODS. 2,335 patients who received single-dose bamlanivimab infusion between November 12, 2020 to February 17, 2021 were compared with a propensity-matched control of 2,335 untreated patients with mild to moderate COVID-19 at Mayo Clinic facilities across 4 states. The primary outcome was the rate of hospitalization at days 14, 21 and 28. RESULTS. The median age of the population was 63; 47.3% of the bamlanivimab-treated cohort were ≥65 years; 49.3% were female. High-risk characteristics included hypertension (54.2%), body mass index ≥35 (32.4%), diabetes mellitus (26.5%), chronic lung disease (25.1%), malignancy (16.6%), and renal disease (14.5%). Patients who received bamlanivimab had lower all-cause hospitalization rates at days 14 (1.5% vs 3.5%; Odds Ratio [OR], 0.38), 21 (1.9% vs 3.9%; OR, 0.46), and 28 (2.5% vs 3.9%; OR, 0.61). Secondary exploratory outcomes included lower intensive care unit admission rates at days 14 (0.14% vs 1%; OR, 0.12), 21 (0.25% vs 1%; OR: 0.24) and 28 (0.56% vs 1.1%; OR: 0.52), and lower all-cause mortality at days 14 (0% vs 0.33%), 21 (0.05% vs 0.4%; OR,0.08) and 28 (0.11% vs 0.44%; OR, 0.01). Adverse events were uncommon with bamlanivimab, occurring in 19/2355, most commonly fever (n=6), nausea (n=5), and lightheadedness (n=3). CONCLUSIONS. Among high-risk patients with mild to moderate COVID-19, treatment with bamlanivimab was associated with a statistically significant lower rate of hospitalization compared with usual care. FUNDING. Mayo Clinic.
Ravindra Ganesh, Colin F. Pawlowski, John C. O'Horo, Lori L. Arndt, Richard F. Arndt, Sarah Bell, Dennis M. Bierle, Molly Destro Borgen, Sara Hanson, Alexander Heyliger, Jennifer L. Larsen, Patrick J. Lenehan, Robert Orenstein, Arjun Puranik, Leigh L. Speicher, Sidna M. Tulledge-Scheitel, AJ Venkatakrishnan, Caroline G. Wilker, Andrew D. Badley, Raymund R. Razonable
BACKGROUND. The angiotensin-converting enzyme (ACE) D allele is more prevalent among African Americans (AA) compared to other races/ethnicities and has previously been associated with severe COVID-19 pathogenesis through excessive ACE1 activity. Angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (ACE-I/ARB) may counteract this mechanism, but their association with COVID-19 outcomes has not been specifically tested in the AA population. METHODS. We identified 6,218 patients who were admitted into Mount Sinai hospitals with COVID-19 between February 24 and May 31, 2020 in the New York City. We evaluated whether the outpatient and in-hospital use of ACE-I/ARB is associated with COVID-19 in-hospital mortality in AA compared with non-AA population. RESULTS. Of the 6,218 COVID-19 patients, 1,138 (18.3%) were ACE-I/ARB users. In a multivariate logistic regression model, ACE-I/ARB use was independently associated with reduced risk of in-hospital mortality in the entire population (OR, 0.655; 95% CI, 0.505-0.850; P=0.001), AA population (OR, 0.44; 95% CI, 0.249-0.779; P=0.005), and non-AA population (OR, 0.748, 95% CI, 0.553-1.012, P=0.06). In the AA population, in-hospital use of ACE-I/ARB was associated with improved mortality (OR, 0.378; 95% CI, 0.188-0.766; P=0.006) while outpatient use was not (OR, 0.889; 95% CI, 0.375-2.158; P=0.812). When analyzing each medication class separately, ARB in-hospital use was significantly associated with reduced in-hospital mortality in the AA population (OR, 0.196; 95% CI, 0.074-0.516; P=0.001), while ACE-I use was not associated with impact on mortality in any population. CONCLUSION. In-hospital use of ARB was associated with a significant reduction in in-hospital mortality among COVID-19-positive AA patients. FUNDING. None.
Shilong Li, Rangaprasad Sarangarajan, Tomi Jun, Yu-Han Kao, Zichen Wang, Ke Hao, Emilio Schadt, Michael A. Kiebish, Elder Granger, Niven R. Narain, Rong Chen, Eric E. Schadt, Li Li
Proper metabolic activities facilitate T cell expansion and antitumor function; however, the mechanisms underlying disruption of the T cell metabolic programme and function in the tumor microenvironment (TME) remain elusive. Here, we show a Zinc finger protein 91 (ZFP91)-governed mechanism disrupting the metabolic pathway and antitumor activity of tumor-infiltrating T cells. Single-cell RNA sequencing revealed that impairments in T cell proliferation and activation correlated with ZFP91 in tissue samples from colorectal cancer patients. T cell-specific deletion of Zfp91 led to enhanced T cell proliferation and potentiated T cell antitumor function. Loss of ZFP91 increased mammalian target of rapamycin complex 1 (mTORC1) activity to drive T cell glycolysis. Mechanistically, T cell antigen receptor (TCR)-dependent ZFP91 cytosolic translocation promoted protein phosphatase 2A (PP2A) complex assembly, thereby restricting mTORC1-mediated metabolic reprogramming. Our results demonstrate that ZFP91 perturbs T cell metabolic and functional states in the TME and suggest that targeting ZFP91 may improve the efficacy of cancer immunotherapy.
Feixiang Wang, Yuerong Zhang, Xiaoyan Yu, Xiao-Lu Teng, Rui Ding, Zhilin Hu, Aiting Wang, Zhengting Wang, Youqiong Ye, Qiang Zou
The secreted protein DEL-1 regulates inflammatory cell recruitment and protects against inflammatory pathologies in animal models. Here, we investigated DEL-1 in inflammatory arthritis using collagen-induced arthritis (CIA) and collagen Ab-induced arthritis (CAIA). In both models, mice with endothelial-specific overexpression of DEL-1 were protected from arthritis relative to WT controls, while arthritis was exacerbated in DEL-1-deficient mice. Compared to WT controls, mice with collagen VI promoter-driven overexpression of DEL-1 in mesenchymal cells were protected against CIA but not CAIA, suggesting a role for DEL-1 in the induction of the arthritogenic Ab response. Indeed, DEL-1 was expressed in perivascular stromal cells of the lymph nodes and inhibited T follicular helper (Tfh) and germinal center B cell responses. Mechanistically, DEL-1 inhibited dendritic cell-dependent induction of Tfh cells by targeting the LFA-1 integrin on T cells. Overall, DEL-1 restrained arthritis through a dual mechanism, one acting locally in the joints and associated with the anti-recruitment function of endothelial cell-derived DEL-1; the other mechanism acting systemically in the lymph nodes and associated with the ability of stromal cell-derived DEL-1 to restrain Tfh responses. DEL-1 may thus be a promising novel therapeutic for the treatment of inflammatory arthritis.
Hui Wang, Xiaofei Li, Tetsuhiro Kajikawa, Jieun Shin, Jong-Hyung Lim, Ioannis Kourtzelis, Kosuke Nagai, Jonathan Korostoff, Sylvia Grossklaus, Ronald Naumann, Triantafyllos Chavakis, George Hajishengallis
ATP11A translocates phosphatidylserine (PtdSer), but not phosphatidylcholine (PtdCho), from the outer to inner leaflet of plasma membranes, thereby maintaining the asymmetric distribution of PtdSer. We herein detected a de novo heterozygous point mutation in ATP11A in a patient with developmental delays and neurological deterioration. Mice carrying the corresponding mutation died perinatally or soon after birth with signs of neurological disorders. This mutation caused an amino acid substitution (Q84E) in the first transmembrane segment of ATP11A, and mutant ATP11A flipped PtdCho. Molecular dynamic simulations revealed that the mutation allowed PtdCho binding at the substrate entry site. Aberrant PtdCho flipping markedly decreased the concentration of PtdCho in the outer leaflet of plasma membranes, whereas sphingomyelin (SM) concentrations in the outer leaflet increased. This change in the distribution of phospholipids altered cell characteristics, including cell growth, cholesterol homeostasis, and sensitivity to sphingomyelinase. MALDI-imaging mass-spectrometry showed a marked increase of SM levels in the brains of Q84E knock-in mouse embryos. These results provide insights into the physiological importance of the substrate specificity of plasma membrane flippases for the proper distribution of PtdCho and SM.
Katsumori Segawa, Atsuo Kikuchi, Tomoyasu Noji, Yuki Sugiura, Keita Hiraga, Chigure Suzuki, Kazuhiro Haginoya, Yasuko Kobayashi, Mitsuhiro Matsunaga, Yuki Ochiai, Kyoko Yamada, Takuo Nishimura, Shinya Iwasawa, Wataru Shoji, Fuminori Sugihara, Kohei Nishino, Hidetaka Kosako, Masahito Ikawa, Yasuo Uchiyama, Makoto Suematsu, Hiroshi Ishikita, Shigeo Kure, Shigekazu Nagata
In recent decades, treatments for myocardial infarction (MI), such as stem and progenitor cell therapy, have attracted considerable scientific and clinical attention but failed to improve patient outcomes. These efforts indicate that more rigorous mechanistic and functional testing of potential MI therapies is required. Recent studies have suggested that augmenting post-MI lymphatic growth via VEGF-C administration improves cardiac function. However, the mechanisms underlying this proposed therapeutic approach remain vague and untested. To more rigorously test the role of lymphatic vessel growth after MI, we examined the post-MI cardiac function of mice in which lymphangiogenesis had been blocked genetically by pan-endothelial or lymphatic endothelial loss of the lymphangiogenic receptor VEGFR3 or global loss of the VEGF-C and VEGF-D ligands. The results obtained using all three genetic approaches were highly concordant and demonstrated that loss of lymphatic vessel growth did not impair left ventricular ejection fraction two weeks after MI in mice. We observed a trend toward excess fluid in the infarcted region of the left ventricle, but immune cell infiltration and clearance were unchanged with loss of expanded lymphatics. These studies refute the hypothesis that lymphangiogenesis contributes significantly to cardiac function after MI, and suggest that any effect of exogenous VEGF-C is likely to be mediated by non-lymphangiogenic mechanisms.
T.C. Stevenson Keller IV, Lillian Lim, Swapnil V. Shewale, Kendra McDaid, Ingrid Marti-Pamies, Alan T. Tang, Carl Wittig, Andrea A. Guerrero, Stephanie Sterling, N. Adrian Leu, marielle scherrer-crosbie, Phyllis A. Gimotty, Mark L. Kahn
Liver tumor-initiating cells (TICs) are involved in liver tumorigenesis, metastasis, drug resistance and relapse, but the regulatory mechanisms of liver TICs are largely unknown. Here, we have identified a functional circular RNA, termed circRNA activating MAFF (cia-MAF), that is robustly expressed in liver cancer and liver TICs. cia-MAF knockout primary cells and cia-maf knockout liver tumors harbor decreased ratios of TICs, and display impaired liver tumorigenesis, self-renewal and metastatic capacities. In contrast, cia-MAF overexpression drives liver TIC propagation, self-renewal and metastasis. Mechanistically, cia-MAF binds to the MAFF promoter, recruits the TIP60 complex to the MAFF promoter, and finally promotes MAFF expression. Loss of cia-MAF function attenuates the combination between the TIP60 complex and the MAFF promoter. MAFF is highly expressed in liver tumors and liver TICs, and its antisense oligo (ASO) has therapeutic potential in treating liver cancer without MAFA/MAFG gene copy number alterations (CNAs). This study reveal an additional layer for liver TIC regulation as well as circRNA function, and also provide an additional target for eliminating liver TICs, especially for liver tumor without MAFA/MAFG gene CNAs.
Zhenzhen Chen, Tiankun Lu, Lan Huang, Zhiwei Wang, Zhongyi Yan, Yubo Guan, Wenjing Hu, Zusen Fan, Pingping Zhu
NKTR-255 is a novel polyethylene glycol (PEG)-conjugate of recombinant human IL-15 (rhIL-15) being examined as a potential cancer immunotherapeutic. Since IL-15 responses can be mediated by trans- or cis-presentation via IL-15Rα or soluble IL-15/IL-15Rα complexes, we investigated the role of IL-15Rα in driving NKTR-255 responses using defined naïve and memory ovalbumin-specific CD8 T cells (OT-I) CD8 T and NK cells in mice. NKTR-255 induced a 2.5 and 2.0-fold expansion of CD8 T and NK cells, respectively in WT mice. In adoptive transfer studies, proliferation of naïve and memory Wt OT-I T cells in response to NKTR-255 was not impaired in IL-15Rα−/− mice, suggesting trans-presentation was not utilized by NKTR-255. Interestingly, naïve IL-15Rα−/− OT-I cells had deficient responses to NKTR-255 while memory IL-15Rα−/− OT-I cell responses were partially impaired, suggesting that naive CD8 T cells are more dependent on cis-presentation of NKTR-255 than memory CD8 T cells. In bone marrow chimeras studies, IL-15Rα−/− and WT NK cells present in WT recipients had similar responses to NKTR-255, suggesting that cis-presentation is not utilized by NK cells. NKTR-255 could form soluble complexes with IL-15Rα; binding to murine IL-15Rα generated superagonists that preferentially stimulated NK cells showing that conversion to IL-15Rβ agonist biases the response towards NK cells. These findings highlight the ability of NKTR-255 to utilize IL-15Rα for cis-presentation and act as an IL-15Rαβ agonist on CD8 T cells.
Tanya O. Robinson, Shweta M. Hegde, Allison J. Chang, Achintyan Gangadharan, Sarai Rivas, Loui Madakamutil, Jonathan Zalevsky, Takahiro Miyazaki, Kimberly S. Schluns
The efficacy of COVID-19 mRNA vaccines is high, but breakthrough infections still occur. We compared the SARS-CoV-2 genomes of 76 breakthrough cases after full vaccination with BNT162b2 (Pfizer/BioNTech), mRNA-1273 (Moderna), or JNJ-78436735 (Janssen) to unvaccinated controls (February-April 2021) in metropolitan New York, including their phylogenetic relationship, distribution of variants, and full spike mutation profiles. Their median age was 48 years; seven required hospitalization and one died. Most breakthrough infections (57/76) occurred with B.1.1.7 (Alpha) or B.1.526 (Iota). Among the 7 hospitalized cases, 4 were infected with B.1.1.7, including 1 death. Both unmatched and matched statistical analyses considering age, sex, vaccine type, and study month as covariates supported the null hypothesis of equal variant distributions between vaccinated and unvaccinated in chi-squared and McNemar tests (p>0.1) highlighting a high vaccine efficacy against B.1.1.7 and B.1.526. There was no clear association among breakthroughs between type of vaccine received and variant. In the vaccinated group, spike mutations in the N-terminal domain and receptor-binding domain that have been associated with immune evasion were overrepresented. The evolving dynamic of SARS-CoV-2 variants requires broad genomic analyses of breakthrough infections to provide real-life information on immune escape mediated by circulating variants and their spike mutations.
Ralf Duerr, Dacia Dimartino, Christian Marier, Paul Zappile, Guiqing Wang, Jennifer Lighter, Brian Elbel, Andrea B. Troxel, Adriana Heguy
BACKGROUND. Chimeric antigen receptor (CAR)-modified T cells have emerged as a novel approach to treat malignant tumors. This strategy has also been proposed for the treatment of HIV-1 infection. We have developed a broadly neutralizing antibody (bNAb)-derived CAR-T cell therapy which can exerted specific cytotoxic activity against HIV-1-infected cells. METHODS. We conducted an open-label trial of the safety, side-effect profile, pharmacokinetic properties, and antiviral activity of bNAb-derived CAR-T cell therapy in HIV-1-infected individuals who were undergoing analytical interruption of antiretroviral therapy (ART). RESULTS. A total of 14 participants completed only a single administration of bNAb-derived CAR-T cells. CAR-T administration was safe and well tolerated. Six participants discontinued ART, and viremia rebound occurred in all of them, with a 5.3-week median time. Notably, the cell-associated viral RNA and intact proviruses decreased significantly after CAR-T treatment. Analyses of HIV-1 variants before or after CAR-T administration suggested that CAR-T cells exerted pressure on rebound viruses, resulting in a selection of viruses with less diversity and mutations against CAR-T-mediated cytotoxicity. CONCLUSIONS. No safety concerns were identified with adoptive transfer of bNAb-derived CAR-T cells. They reduced viral reservoir. All the rebounds were due to preexisting or emergence of viral escape mutations. TRIAL REGISTRATION. ClinicalTrials.gov number, NCT03240328. FUNDING. Ministry of Science and Technology of China, National Natural Science Foundation of China, and Department of Science and Technology of Guangdong Province.
Bingfeng Liu, Wanying Zhang, Baijin Xia, Shuliang Jing, Yingying Du, Fan Zou, Rong Li, Lijuan Lu, Shaozhen Chen, Yonghong Li, Qifei Hu, Yingtong Lin, Yiwen Zhang, Zhangping He, Xu Zhang, Xiejie Chen, Tao Peng, Xiaoping Tang, Weiping Cai, Ting Pan, Linghua Li, Hui Zhang
Dementia resulting from small vessel diseases of the brain (SVDs) is an emerging epidemic for which there is no treatment. Hypertension is the major risk factor for SVDs, but how hypertension damages the brain microcirculation is unclear. Here, we show that chronic hypertension in a mouse model progressively disrupts on-demand delivery of blood to metabolically active areas of the brain (functional hyperemia) through diminished activity of the capillary endothelial cell inward-rectifier potassium channel, Kir2.1. Despite similar efficacy in reducing blood pressure, amlodipine, a voltage-dependent calcium-channel blocker, prevented hypertension-related damage to functional hyperemia whereas losartan, an angiotensin II type-1 receptor blocker, did not. We attribute this drug class effect to losartan-induced ‘aldosterone breakthrough’, a phenomenon triggered by pharmacological interruption of the renin-angiotensin pathway leading to elevated plasma aldosterone levels. This hypothesis is supported by the finding that combining losartan with the aldosterone receptor antagonist eplerenone prevented the hypertension-related decline in functional hyperemia. Collectively, these data suggest Kir2.1 as a possible therapeutic target in vascular dementia and indicate that concurrent mineralocorticoid aldosterone receptor blockade may aid in protecting against late-life cognitive decline in hypertensive patients treated with angiotensin II type-1 receptor blockers.
Masayo Koide, Osama F. Harraz, Fabrice Dabertrand, Thomas A. Longden, Hannah R. Ferris, George C. Wellman, David C. Hill-Eubanks, Adam S. Greenstein, Mark Nelson
Decreased skeletal muscle strength and mitochondrial dysfunction are characteristic of diabetes. Action of insulin and IGF-1 through insulin receptor (IR) and IGF-1 receptor (IGF1R) maintain muscle mass via suppression of FoxOs, but whether FoxO activation coordinates atrophy in concert with mitochondrial dysfunction is unknown. We show that mitochondrial respiration and complex-I activity were decreased in streptozotocin (STZ) diabetic muscle, but these defects were reversed following muscle-specific FoxO1/3/4 triple knockout in STZ-FoxO TKO. In the absence of systemic glucose or lipid abnormalities, muscle-specific IR knockout (M-IR-/-) or combined IR/IGF1R knockout (MIGIRKO) impaired mitochondrial respiration, decreased ATP production, and increased ROS. These mitochondrial abnormalities were not present in muscle-specific IR/IGF1R and FoxO1/3/4 quintuple knockout mice (M-QKO). Acute tamoxifen-inducible deletion of IR/IGF1R also decreased muscle pyruvate respiration, complex-I activity, and supercomplex assembly. Although autophagy was increased when IR/IGF1R were deleted in muscle, mitophagy was not increased. Mechanistically, RNA-seq revealed that complex-I core subunits were decreased in STZ-diabetic and MIGIRKO muscle, and these changes were not present with FoxO knockout in STZ-FoxO TKO and M-QKO. Thus, insulin-deficient diabetes or loss of insulin/IGF-1 action in muscle decreases complex-I driven mitochondrial respiration and supercomplex assembly, in part by FoxO-mediated repression of Complex-I subunit expression.
Gourav Bhardwaj, Christie M. Penniman, Jayashree Jena, Pablo A. Suarez Beltran, Collin Foster, Kennedy Poro, Taylor L. Junck, Antentor O. Hinton Jr., Rhonda Souvenir, Jordan D. Fuqua, Pablo E. Morales, Roberto Bravo-Sagua, William I. Sivitz, Vitor A. Lira, E. Dale Abel, Brian T. O'Neill
IL-1β is a pro-inflammatory mediator with roles in innate and adaptive immunity. Here we show that IL-1β contributes to autoimmune arthritis by inducing osteoclastogenic capacity in T regulatory cells (Tregs). Using mice with joint inflammation arising through deficiency of the IL-1 receptor antagonist (Il1rn-/-), we observed that IL-1β blockade attenuated disease more effectively in early arthritis than in established arthritis, especially with respect to bone erosion. Protection was accompanied by a reduction in synovial CD4+Foxp3+ Tregs that displayed preserved suppressive capacity and aerobic metabolism but aberrant expression of RANKL and a striking capacity to drive RANKL-dependent osteoclast differentiation. Both Il1rn-/- Tregs and wild-type Tregs differentiated with IL-1β accelerated bone erosion upon adoptive transfer. Human Tregs exhibited analogous differentiation, and corresponding RANKLhiFoxp3+ T cells could be identified in rheumatoid arthritis synovial tissue. Together, these findings identify IL-1β-induced osteoclastogenic Tregs (O-Tregs) as a contributor to bone erosion in arthritis.
Anaïs Levescot, Margaret H. Chang, Julia Schnell, Nathan Nelson-Maney, Jing Yan, Marta Martínez-Bonet, Ricardo Grieshaber-Bouyer, Pui Y. Lee, Kevin Wei, Rachel B. Blaustein, Allyn Morris, Alexandra Wactor, Yoichiro Iwakura, James A. Lederer, Deepak A. Rao, Julia F. Charles, Peter A. Nigrovic
BACKGROUND. Germline mutations in telomerase and other telomere maintenance genes manifest in the premature aging short telomere syndromes. Myelodysplastic syndromes and acute myeloid leukemia (MDS/AML) account for 75% of associated malignancies, but how these cancers overcome the inherited telomere defect is unknown. METHODS. We used ultra-deep targeted sequencing to detect somatic reversion mutations in 17 candidate telomere lengthening genes among controls and short telomere syndrome patients with and without MDS/AML and we tested the functional significance of these mutations. RESULTS. While no controls carried somatic mutations in telomere maintenance genes, 29% (16 of 56) of adults with germline telomere maintenance defects carried at least one (P<0.001) and 13% (7 of 56) had 2 or more. In addition to TERT promoter mutations which were present in 19%, we identified POT1 and TERF2IP mutations in 13%. POT1 mutations impaired telomere binding in vitro and some mutations were identical to ones seen in familial melanoma associated with longer telomere length. Exclusively in patients with germline defects in telomerase RNA (TR), we identified somatic mutations in nuclear RNA exosome genes, RBM7, SKIV2L2, and DIS3, where loss-of-function upregulates mature TR levels. Somatic reversion events in six telomere-related genes were more prevalent in patients who were MDS/AML-free (P = 0.02, RR 4.4, 95% CI 1.2-16.7), and no MDS/AML patient had more than one reversion mutation. CONCLUSIONS. Our data identify diverse adaptive somatic mechanisms in the short telomere syndrome; they raise the possibility that their presence alleviates the telomere crisis that promotes transformation to MDS/AML.
Kristen E. Schratz, Valeriya Gaysinskaya, Zoe L. Cosner, Emily A. DeBoy, Zhimin Xiang, Laura Kasch-Semenza, Liliana Florea, Pali D. Shah, Mary Armanios
Hypothalamic glucose sensing enables an organism to match energy expenditure and food intake to circulating levels of glucose, the main energy source of the brain. Here, we established that tanycytes of the hypothalamic arcuate nucleus, specialized glia that line the wall of the third ventricle, convert brain glucose supplies into lactate that they transmit through monocarboxylate transporters to arcuate proopiomelanocortin neurons, which integrate this signal to drive their activity and to adapt the metabolic response to meet physiological demands. Furthermore, this transmission required the formation of extensive Connexin-43 gap-junction-mediated metabolic networks by arcuate tanycytes. Selectively suppressing either tanycytic monocarboxylate transporters or gap junctions resulted in altered feeding behavior and energy metabolism. Tanycytic intercellular communication and lactate production are thus integral to the mechanism by which hypothalamic neurons that regulate energy and glucose homeostasis efficiently perceive alterations in systemic glucose levels as a function of the physiological state of the organism.
Tori Lhomme, Jerome Clasadonte, Monica Imbernon, Daniela Fernandois, Florent Sauve, Emilie Caron, Natalia Lima, Violeta Heras, Ines Martinez-Corral, Helge Müller-Fielitz, S. Rasika, Markus Schwaninger, Ruben Nogueiras, Vincent Prevot
Ischemic cardiomyopathy is associated with an increased risk of sudden death, activation of the unfolded protein response (UPR), and reductions in multiple cardiac ion channels. When activated, the protein kinase-like ER kinase (PERK) branch of the UPR reduces protein translation and abundance. We hypothesized that PERK inhibition could prevent ion channel downregulation and reduce arrhythmic risk after myocardial infarct (MI). MI induced by coronary artery ligation resulted in mice exhibited reduced ion channel levels, ventricular tachycardia (VT), and prolonged corrected intervals between the Q and T waves of the ECGs (QTc). Protein levels of major cardiac ion channels were decreased. MI cardiomyocytes showed significantly prolonged action potential duration and decreased maximum upstroke velocity. Cardiac-specific PERK knockout (PERKKO) reduced electrical remodeling in response to MI with shortened QTc intervals, less VT episodes, and higher survival rates (P<0.05 vs. MI). Pharmacological PERK inhibition had similar effects. In conclusion, activated PERK during MI contributed to arrhythmic risk by downregulation of select cardiac ion channels. PERK inhibition prevented these changes and reduced arrhythmic risk. These results suggest that ion channel downregulation during MI is a fundamental arrhythmic mechanism and maintaining ion channel levels is antiarrhythmic.
Man Liu, Hong Liu, Preethy Parthiban, Gyeoung-Jin Kang, Guangbin Shi, Feng Feng, Anyu Zhou, Lianzhi Gu, Courtney Karnopp, Elena G. Tolkacheva, Samuel C. Dudley
Natural killer (NK) cell suppression of T cells is a key determinant of viral pathogenesis and vaccine efficacy. This process involves perforin-dependent elimination of activated CD4 T cells during the first three days of infection. Although this mechanism requires cell-cell contact, NK cells and T cells typically reside in different compartments of lymphoid tissues at steady state. Here, we showed that NK-cell suppression of T cells is associated with transient accumulation of NK cells within T cell-rich sites of the spleen during lymphocytic choriomeningitis virus infection. The chemokine receptor CXCR3 was required for this relocation and suppression of antiviral T cells. Accordingly, NK-cell migration was mediated by type I interferon (IFN)-dependent promotion of CXCR3 ligand expression. In contrast, adenoviral vectors that weakly induced type I IFN and did not stimulate NK-cell inhibition of T cells also did not promote measurable redistribution of NK cells to T-cell zones. Exogenous IFN rescued NK-cell migration during adenoviral vector immunization. Thus, type I IFN and CXCR3 were critical for properly positioning NK cells to constrain antiviral T-cell responses. Development of strategies to curtail migration of NK cells between lymphoid compartments may enhance vaccine-elicited immune responses.
Ayad Ali, Laura M. Canaday, H. Alex Feldman, Hilal Cevik, Michael T. Moran, Sanjeeth Rajaram, Nora Lakes, Jasmine A. Tuazon, Harsha Seelamneni, Durga Krishnamurthy, Eryn Blass, Dan H. Barouch, Stephen N. Waggoner
The start codon c.1A>G mutation in KLHL24, encoding ubiquitin-ligase KLHL24, results in the loss of 28 N-terminal amino acids (KLHL24-ΔN28) by skipping the initial start codon. In skin, KLHL24-ΔN28 leads to gain of function, excessively targeting intermediate filament keratin-14 for proteasomal degradation, ultimately causing epidermolysis bullosa simplex (EBS). The majority of these EBS-patients are also diagnosed with dilated cardiomyopathy (DCM), but the pathological mechanism in the heart is unknown. As desmin is the cardiac homologue of keratin-14, we hypothesized that KLHL24-ΔN28 leads to excessive degradation of desmin, resulting in DCM. Dynamically loaded engineered heart tissues (dyn-EHTs) were generated from human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes from two patients and three (non)familial controls. Ten-fold lower desmin protein levels were observed in patient-derived dyn-EHTs, in line with diminished desmin levels detected in patients’ explanted heart. This was accompanied by tissue dilatation, impaired mitochondrial function, decreased force values and increased cardiomyocyte stress. HEK293 transfection studies confirmed KLHL24-mediated desmin degradation. KLHL24 RNA interference or direct desmin overexpression recovered desmin protein levels, restoring morphology and function in patient-derived dyn-EHTs. To conclude, presence of KLHL24-ΔN28 in cardiomyocytes leads to excessive degradation of desmin, affecting tissue morphology and function, that can be prevented by restoring desmin protein levels.
Mathilde C.S.C. Vermeer, Maria C. Bolling, Jacqueline M. Bliley, Karla F. Arevalo Gomez, Mario G. Pavez-Giani, Duco Kramer, Pedro H. Romero-Herrera, B. Daan Westenbrink, Gilles F.H. Diercks, Maarten P. van den Berg, Adam W. Feinberg, Herman H. W. Silljé, Peter van der Meer
Alcohol use disorder (AUD) is associated with substantial morbidity, mortality, and societal cost, and pharmacological treatment options for AUD are limited. The endogenous cannabinoid (eCB) signaling system is critically involved in reward processing and alcohol intake is positively correlated with release of the eCB ligand 2-Arachidonoylglycerol (2-AG) within reward neurocircuitry. Here we show that genetic and pharmacological inhibition of diacylglycerol lipase (DAGL), the rate limiting enzyme in the synthesis of 2-AG, reduces alcohol consumption in a variety of preclinical models ranging from a voluntary free-access model to aversion resistant-drinking and dependence-like drinking induced via chronic intermittent ethanol vapor exposure in mice. DAGL inhibition during either chronic alcohol consumption or protracted withdrawal was devoid of anxiogenic and depressive-like behavioral effects. Lastly, DAGL inhibition also prevented ethanol-induced suppression of GABAergic transmission onto midbrain dopamine neurons, providing mechanistic insight into how DAGL inhibition could affect alcohol reward. These data suggest reducing 2-AG signaling via inhibition of DAGL could represent an effective approach to reduce alcohol consumption across the spectrum of AUD severity.
Nathan D. Winters, Gaurav Bedse, Anastasia A. Astafyev, Toni A. Patrick, Megan Altemus, Amanda J. Morgan, Snigdha Mukerjee, Keenan D. Johnson, Vikrant R. Mahajan, Md. Jashim Uddin, Philip J. Kingsley, Samuel W. Centanni, Cody A. Siciliano, David C. Samuels, Lawrence J. Marnett, Danny G. Winder, Sachin Patel
Intratumoral T cells that might otherwise control tumors are often identified in an ‘exhausted’ state, defined by specific epigenetic modifications and upregulation of genes such as CD38, CTLA-4 and PD-1. While the term might imply inactivity, there has been little study of this state at the phenotypic level in tumors to understand the extent of their incapacitation. Starting with the observation that T cells move more quickly through mouse tumors as residence time increases and they progress towards exhaustion, we elaborated a non-stimulatory live-biopsy method for real-time study of T cell behaviors within individual patient tumors. Using two-photon microscopy, we studied native CD8 T cells interacting with APCs and cancer cells in different micro-niches of human tumors, finding that T cell speed was variable by region and by patient and was inversely correlated with local tumor density. Across a range of tumor types, we found a strong relationship between CD8 T cell motility and exhausted T cell state that corresponds to observations made in mouse models where exhausted T cells move faster. Our study demonstrates T cell dynamic states in individual human tumors and supports the existence of an active program in ‘exhausted’ T cells that extends beyond incapacitating them.
Ran You, Jordan Artichoker, Adam Fries, Austin W. Edwards, Alexis J. Combes, Gabriella C. Reeder, Bushra Samad, Matthew F. Krummel