Long-term impairment in T cell–mediated adaptive immunity is a major clinical obstacle following treatment of blood disorders with hematopoietic stem cell transplantation. Although T cell development in the thymus has been extensively characterized, there are significant gaps in our understanding of prethymic processes that influence early T cell potential. We have uncovered a Notch/IL-21 signaling axis in bone marrow common lymphoid progenitor (CLP) cells. IL-21 receptor expression was driven by Notch activation in CLPs, and in vivo treatment with IL-21 induced Notch-dependent CLP proliferation. Taking advantage of this potentially novel signaling axis, we generated T cell progenitors ex vivo, which improved repopulation of the thymus and peripheral lymphoid organs of mice in an allogeneic transplant model. Importantly, Notch and IL-21 activation were equally effective in the priming and expansion of human cord blood cells toward the T cell fate, confirming the translational potential of the combined treatment.
Kilian Sottoriva, Na Yoon Paik, Zachary White, Thilinie Bandara, Lijian Shao, Teruyuki Sano, Kostandin V. Pajcini
Transplant recipients exhibit an impaired protective immunity after SARS-CoV-2 vaccination, potentially caused by mycophenolate (MPA) immunosuppression. Recent data from patients with autoimmune disorders suggest that temporary MPA hold might greatly improve booster vaccination outcomes. We applied a fourth dose of SARS-CoV-2 vaccine to 29 kidney transplant recipients during a temporary (5 weeks) MPA/azathioprine hold, who had not mounted a humoral immune response to previous vaccinations. Seroconversion until day 32 after vaccination was observed in 76% of patients, associated with acquisition of virus-neutralizing capacity. Interestingly, 21/25 (84%) calcineurin inhibitor–treated patients responded, but only 1/4 belatacept-treated patients responded. In line with humoral responses, counts and relative frequencies of spike receptor binding domain–specific (RBD-specific) B cells were markedly increased on day 7 after vaccination, with an increase in RBD-specific CD27++CD38+ plasmablasts. Whereas overall proportions of spike-reactive CD4+ T cells remained unaltered after the fourth dose, frequencies were positively correlated with specific IgG levels. Importantly, antigen-specific proliferating Ki67+ and in vivo–activated programmed cell death 1–positive T cells significantly increased after revaccination during MPA hold, whereas cytokine production and memory differentiation remained unaffected. In summary, antimetabolite hold augmented all arms of immunity during booster vaccination. These data suggest further studies of antimetabolite hold in kidney transplant recipients.
Eva Schrezenmeier, Hector Rincon-Arevalo, Annika Jens, Ana-Luisa Stefanski, Charlotte Hammett, Bilgin Osmanodja, Nadine Koch, Bianca Zukunft, Julia Beck, Michael Oellerich, Vanessa Proß, Carolin Stahl, Mira Choi, Friederike Bachmann, Lutz Liefeldt, Petra Glander, Ekkehard Schütz, Kirsten Bornemann-Kolatzki, Covadonga López del Moral, Hubert Schrezenmeier, Carolin Ludwig, Bernd Jahrsdörfer, Kai-Uwe Eckardt, Nils Lachmann, Katja Kotsch, Thomas Dörner, Fabian Halleck, Arne Sattler, Klemens Budde
HIV-1 vaccine efforts are primarily directed toward eliciting neutralizing antibodies (nAbs). However, vaccine trials and mother-to-child natural history cohort investigations indicate that antibody-dependent cellular cytotoxicity (ADCC), not nAbs, correlate with prevention. The ADCC characteristics associated with lack of HIV-1 acquisition remain unclear. Here, we examine ADCC and nAb properties in pretransmission plasma from HIV-1–exposed infants and from the corresponding transmitting and nontransmitting mothers’ breast milk and plasma. Breadth and potency (BP) were assessed against a panel of heterologous, nonmaternal variants. ADCC and neutralization sensitivity were estimated for the strains in the infected mothers. Infants who eventually acquired HIV-1 and those who remained uninfected had similar pretransmission ADCCBP. Viruses circulating in the transmitting and nontransmitting mothers had similar ADCC susceptibility. Infants with higher pretransmission ADCCBP and exposure to more ADCC-susceptible strains were less likely to acquire HIV-1. In contrast, higher preexisting infant neutralization BP and greater maternal virus neutralization sensitivity did not associate with transmission. Infants had higher ADCCBP closer to birth and in the presence of high plasma IgG relative to IgA levels. Mothers with potent humoral responses against their autologous viruses harbored more ADCC-sensitive strains. ADCC sensitivity of the exposure variants and preexisting ADCCBP influenced mother-to-child HIV-1 transmission during breastfeeding. Vaccination strategies that enhance ADCC are likely insufficient to prevent HIV-1 transmission because some strains may have low ADCC susceptibility.
Allison S. Thomas, Carolyn Coote, Yvetane Moreau, John E. Isaac, Alexander C. Ewing, Athena P. Kourtis, Manish Sagar
Binding of the bromodomain and extraterminal domain proteins (BETs) to acetylated histone residues is critical for gene transcription. We sought to determine the antifibrotic efficacy and potential mechanisms of BET inhibition in systemic sclerosis (SSc). Blockade of BETs was done using a pan-BET inhibitor, JQ1; BRD2 inhibitor, BIC1; or BRD4 inhibitors AZD5153 or ARV825. BET inhibition, specifically BRD4 blockade, showed antifibrotic effects in an animal model of SSc and in patient-derived diffuse cutaneous SSc (dcSSc) fibroblasts. Transcriptome analysis of JQ1-treated dcSSc fibroblasts revealed differentially expressed genes related to extracellular matrix, cell cycle, and calcium (Ca2+) signaling. The antifibrotic effect of BRD4 inhibition was mediated at least in part by downregulation of Ca2+/calmodulin–dependent protein kinase II α and reduction of intracellular Ca2+ concentrations. On the basis of these results, we propose targeting Ca2+ pathways or BRD4 as potentially novel therapeutic approaches for progressive tissue fibrosis.
Sirapa Vichaikul, Mikel Gurrea-Rubio, M. Asif Amin, Phillip L. Campbell, Qi Wu, Megan N. Mattichak, William D. Brodie, Pamela J. Palisoc, Mustafa Ali, Sei Muraoka, Jeffrey H. Ruth, Ellen N. Model, Dallas M. Rohraff, Jonatan L. Hervoso, Yang Mao-Draayer, David A. Fox, Dinesh Khanna, Amr H. Sawalha, Pei-Suen Tsou
Greater than 25% of all men develop an inguinal hernia in their lifetime, and more than 20 million inguinal hernia repair surgeries are performed worldwide each year. The mechanisms causing abdominal muscle weakness, the formation of inguinal hernias, or their recurrence are largely unknown. We previously reported that excessively produced estrogen in the lower abdominal muscles (LAMs) triggers extensive LAM fibrosis, leading to hernia formation in a transgenic male mouse model expressing the human aromatase gene (Aromhum). To understand the cellular basis of estrogen-driven muscle fibrosis, we performed single-cell RNA sequencing on LAM tissue from Aromhum and wild-type littermates. We found a fibroblast-like cell group composed of 6 clusters, 2 of which were validated for their enrichment in Aromhum LAM tissue. One of the potentially novel hernia-associated fibroblast clusters in Aromhum was enriched for the estrogen receptor-α gene (Esr1hi). Esr1hi fibroblasts maximally expressed estrogen target genes and seemed to serve as the progenitors of another cluster expressing ECM-altering enzymes (Mmp3hi) and to upregulate expression of proinflammatory, profibrotic genes. The discovery of these 2 potentially novel and unique hernia-associated fibroblasts may lead to the development of novel treatments that can nonsurgically prevent or reverse inguinal hernias.
Tanvi Potluri, Matthew J. Taylor, Jonah J. Stulberg, Richard L. Lieber, Hong Zhao, Serdar E. Bulun
Uveal melanoma (UM) is a unique disease in that patients with primary UM are well stratified based on their risk of developing metastasis, yet there are limited effective treatments once metastases occur. There is an urgent need to better understand the distinct molecular pathogenesis of UM and the characteristics of patients at high risk for metastasis to identify neoantigenic targets that can be used in immunotherapy and to develop novel therapeutic strategies that may effectively target this lethal transition. An important and overlooked area of molecular pathogenesis and neoantigenic targets in UM comes from human endogenous retroviruses (HERVs). We investigated the HERV expression landscape in primary UM and found that tumors were stratified into 4 HERV-based subsets that provide clear delineation of risk outcome and support subtypes identified by other molecular indicators. Specific HERV loci are associated with the risk of uveal melanoma metastasis and may offer mechanistic insights into this process, including dysregulation of HERVs on chromosomes 3 and 8. A HERV signature composed of 17 loci was sufficient to classify tumors according to subtype with greater than 95% accuracy, including at least 1 intergenic HERV with coding potential (HERVE_Xp11.23) that could represent a potential HERV E target for immunotherapy.
Matthew L. Bendall, Jasmine H. Francis, Alexander N. Shoushtari, Douglas F. Nixon
Atrial natriuretic peptide (ANP), encoded by Nppa, is a vasodilatory hormone that promotes salt excretion. Genome-wide association studies identified Nppa as a causative factor of blood pressure development, and in humans, ANP levels were suggested as an indicator of salt sensitivity. This study aimed to provide insights into the effects of ANP on cardiorenal function in salt-sensitive hypertension. To address this question, hypertension was induced in SSNPPA–/– (KO of Nppa in the Dahl salt-sensitive [SS] rat background) or SSWT (WT Dahl SS) rats by a high-salt (HS) diet challenge (4% NaCl for 21 days). Chronic infusion of ANP in SSWT rats attenuated the increase in blood pressure and cardiorenal damage. Overall, the SSNPPA–/– strain demonstrated higher blood pressure and intensified cardiac fibrosis (with no changes in ejection fraction) compared with SSWT rats. Furthermore, SSNPPA–/– rats exhibited kidney hypertrophy and higher glomerular injury scores, reduced diuresis, and lower sodium and chloride excretion than SSWT when fed a HS diet. Additionally, the activity of epithelial Na+ channel (ENaC) was found to be increased in the collecting ducts of the SSNPPA–/– rats. Taken together, these data show promise for the therapeutic benefits of ANP and ANP-increasing drugs for treating salt-sensitive hypertension.
Daria V. Ilatovskaya, Vladislav Levchenko, Kristen Winsor, Gregory R. Blass, Denisha R. Spires, Elizaveta Sarsenova, Iuliia Polina, Adrian Zietara, Mark Paterson, Alison J. Kriegel, Alexander Staruschenko
Post-exertional malaise (PEM) is a hallmark symptom of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). We monitored the evolution of 1157 plasma metabolites in 60 ME/CFS (45 female, 15 male) and 45 matched healthy control participants (30 female, 15 male) before and after 2 maximal cardiopulmonary exercise test (CPET) challenges separated by 24 hours, with the intent of provoking PEM in patients. Four time points allowed exploration of the metabolic response to maximal energy-producing capacity and the recovery pattern of participants with ME/CFS compared with the healthy control group. Baseline comparison identified several significantly different metabolites, along with an enriched percentage of yet-to-be identified compounds. Additionally, temporal measures demonstrated an increased metabolic disparity between cohorts, including unknown metabolites. The effects of exertion in the ME/CFS cohort predominantly highlighted lipid-related as well as energy-related pathways and chemical structure clusters, which were disparately affected by the first and second exercise sessions. The 24-hour recovery period was distinct in the ME/CFS cohort, with over a quarter of the identified pathways statistically different from the controls. The pathways that are uniquely different 24 hours after an exercise challenge provide clues to metabolic disruptions that lead to PEM. Numerous altered pathways were observed to depend on glutamate metabolism, a crucial component of the homeostasis of many organs in the body, including the brain.
Arnaud Germain, Ludovic Giloteaux, Geoffrey E. Moore, Susan M. Levine, John K. Chia, Betsy A. Keller, Jared Stevens, Carl J. Franconi, Xiangling Mao, Dikoma C. Shungu, Andrew Grimson, Maureen R. Hanson
Arterial stiffness predicts cardiovascular disease and all-cause mortality, but its treatment remains challenging. Mice treated with angiotensin II (Ang II) develop hypertension, arterial stiffness, vascular dysfunction, and a downregulation of Rho-related BTB domain–containing protein 1 (RhoBTB1) in the vasculature. RhoBTB1 is associated with blood pressure regulation, but its function is poorly understood. We tested the hypothesis that restoring RhoBTB1 can attenuate arterial stiffness, hypertension, and vascular dysfunction in Ang II–treated mice. Genetic complementation of RhoBTB1 in the vasculature was achieved using mice expressing a tamoxifen-inducible, smooth muscle–specific RhoBTB1 transgene. RhoBTB1 restoration efficiently and rapidly alleviated arterial stiffness but not hypertension or vascular dysfunction. Mechanistic studies revealed that RhoBTB1 had no substantial effect on several classical arterial stiffness contributors, such as collagen deposition, elastin content, and vascular smooth muscle remodeling. Instead, Ang II increased actin polymerization in the aorta, which was reversed by RhoBTB1. Changes in the levels of 2 regulators of actin polymerization, cofilin and vasodilator-stimulated phosphoprotein, in response to RhoBTB1 were consistent with an actin depolymerization mechanism. Our study reveals an important function of RhoBTB1, demonstrates its vital role in antagonizing established arterial stiffness, and further supports a functional and mechanistic separation among hypertension, vascular dysfunction, and arterial stiffness.
Shi Fang, Jing Wu, John J. Reho, Ko-Ting Lu, Daniel T. Brozoski, Gaurav Kumar, Alec M. Werthman, Sebastiao Donato Silva Jr., Patricia C. Muskus Veitia, Kelsey K. Wackman, Angela J. Mathison, Bi Qing Teng, Chien-Wei Lin, Frederick W. Quelle, Curt D. Sigmund
It is currently thought that UVB radiation drives photoaging of the skin primarily by generating ROS. In this model, ROS purportedly activates activator protein-1 to upregulate MMPs 1, 3, and 9, which then degrade collagen and other extracellular matrix components to produce wrinkles. However, these MMPs are expressed at relatively low levels and correlate poorly with wrinkles, suggesting that another mechanism distinct from ROS and MMP1/3/9 may be more directly associated with photoaging. Here we show that MMP2, which degrades type IV collagen, is abundantly expressed in human skin, increases with age in sun-exposed skin, and correlates robustly with aryl hydrocarbon receptor (AhR), a transcription factor directly activated by UV-generated photometabolites. Through mechanistic studies with HaCaT human immortalized keratinocytes, we found that AhR, specificity protein 1 (SP1), and other pathways associated with DNA damage are required for the induction of both MMP2 and MMP11 (another MMP implicated in photoaging), but not MMP1/3. Last, we found that topical treatment with AhR antagonists vitamin B12 and folic acid ameliorated UVB-induced wrinkle formation in mice while dampening MMP2 expression in the skin. These results directly implicate DNA damage in photoaging and reveal AhR as a potential target for preventing wrinkles.
Daniel J. Kim, Akiko Iwasaki, Anna L. Chien, Sewon Kang
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