A human STAT3 gain-of-function variant confers T cell dysregulation without predominant Treg dysfunction in mice

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Abstract

Primary immune regulatory disorders (PIRD) are a group of disorders characterized by immune dysregulation, presenting with a wide range of clinical disease including autoimmunity, autoinflammation, or lymphoproliferation. Autosomal dominant germline gain-of-function (GOF) variants in STAT3 result in a PIRD with a broad clinical spectrum. Studies in patients have documented a decreased frequency of FOXP3+ regulatory T (Treg) cells and an increased frequency of Th17 cells in some patients with active disease. However, the mechanisms of disease pathogenesis in STAT3 GOF syndrome remain largely unknown, and treatment is challenging. We developed a knock-in mouse model harboring a de novo pathogenic human STAT3 variant (p.G421R) and found these mice developed T cell dysregulation, lymphoproliferation and CD4+ Th1 cell skewing. Surprisingly, Treg cell numbers, phenotype, and function remained largely intact, however mice had a selective deficiency in the generation of iTreg cells. In parallel, we performed single-cell RNA-sequencing on T cells from STAT3 GOF patients. We demonstrate only minor changes in the Treg cell transcriptional signature and an expanded, effector CD8+ T cell population. Together, these findings suggest Treg cells are not the primary driver of disease and highlight the importance of preclinical models in the study of disease mechanisms in rare PIRD.

Authors

Erica G. Schmitt, Kelsey A. Toth, Samuel I. Risma, Ana Kolicheski, Nermina Saucier, Rafael J. Feliciano Berríos, Zev J. Greenberg, Jennifer W. Leiding, Jack J. Bleesing, Akaluck Thatayatikom, Laura G. Schuettpelz, John R. Edwards, Tiphanie P. Vogel, Megan A. Cooper

Lower SARS-CoV-2 specific humoral immunity in People Living with HIV-1 recovered from non-hospitalized COVID-19

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Abstract

People living with HIV-1 (PLWH) exhibit more rapid antibody decline following routine immunization and elevated baseline chronic inflammation than people without HIV-1 (PWOH), indicating potential for diminished humoral immunity during SARS-CoV-2 infection. Conflicting reports have emerged on the ability of PLWH to maintain humoral protection against SARS-CoV-2 co-infection during convalescence. It is unknown if peak COVID-19 severity, along with HIV-1 infection status, associates with the quality and quantity of humoral immunity following recovery. Using a cross-sectional observational cohort from the USA and Peru, adults were enrolled 1-10 weeks post-SARS-CoV-2 infection diagnosis or symptom resolution. Serum antibodies were analyzed for SARS-CoV-2-specific response rates, binding magnitudes, ACE2 receptor blocking and antibody dependent cellular phagocytosis (ADCP). Overall, (1) PLWH exhibited a trend towards decreased magnitude of SARS-CoV-2-specific antibodies, despite modestly increased overall response rates when compared to PWOH, (2) PLWH recovered from symptomatic outpatient COVID-19 had comparatively diminished immune responses, and (3) PLWH lacked a corresponding increase in SARS-CoV-2 antibodies with increased COVID-19 severity when comparing asymptomatic to symptomatic outpatient disease.

Authors

Daniel J. Schuster, Shelly Karuna, Caroline Brackett, Martina S. Wesley, Shuying S. Li, Nathan Eisel, DeAnna Tenney, Sir'Tauria Hilliard, Nicole L. Yates, Jack R. Heptinstall, LaTonya D. Williams, Xiaoying Shen, Robert Rolfe, Robinson Cabello, Lu Zhang, Sheetal Sawant, Jiani Hu, April Kaur Randhawa, Ollivier Hyrien, John A. Hural, Lawrence Corey, Ian Frank, Georgia D. Tomaras, Kelly E. Seaton

Preclinical testing of dabigatran in trypsin-dependent pancreatitis

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Abstract

Pancreatitis, the inflammatory disorder of the pancreas, has no specific therapy. Genetic, biochemical and animal model studies revealed that trypsin plays a central role in the onset and progression of pancreatitis. Here, we performed biochemical and preclinical mouse experiments to offer proof of concept that orally administered dabigatran etexilate can inhibit pancreatic trypsins and shows therapeutic efficacy in trypsin-dependent pancreatitis. We found that dabigatran competitively inhibited all human and mouse trypsin isoforms (Ki range 10-79 nM) and dabigatran plasma concentrations in mice given oral dabigatran etexilate well exceeded the Ki of trypsin inhibition. In the T7K24R trypsinogen mutant mouse model, a single oral gavage of dabigatran etexilate was effective against cerulein-induced progressive pancreatitis with a high degree of histological normalization. In contrast, spontaneous pancreatitis in T7D23A mice, which carry a more aggressive trypsinogen mutation, was not ameliorated by dabigatran etexilate, given either as daily gavages or by mixing it with solid chow. Taken together, our observations confirmed that benzamidine derivatives such as dabigatran are potent trypsin inhibitors and show therapeutic activity against trypsin-dependent pancreatitis in T7K24R mice. Lack of efficacy in T7D23A mice is likely related to the more severe pathology and insufficient drug concentrations in the pancreas.

Authors

Zsófia G. Pesei, Zsanett Jancsó, Alexandra Demcsák, Balázs Csaba Németh, Sandor Vajda, Miklós Sahin-Tóth

The whole-cell pertussis vaccine imposes a broad effector B-cell response in mouse heterologous prime-boost settings

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Abstract

Since the introduction of new generation pertussis vaccines, resurgence of pertussis is observed in many developed countries. Former whole-cell pertussis vaccines (wP) are able to protect against disease and transmission but have been replaced in several industrialized countries because of their reactogenicity and adverse effects. Current acellular pertussis vaccines (aP), made of purified proteins of Bordetella pertussis, are efficient at preventing disease but fail to induce long-term protection from infection. While the systemic and mucosal T cell immunity induced by the two types of vaccines has been well described, much less is known concerning B cell responses. Taking advantage of an inducible AID fate-mapping mouse model, we compared effector and memory B cells induced by the two classes of vaccines and showed that a stronger and broader memory B cell and plasma cell response is achieved by a wP prime. We also observed that homologous or heterologous vaccine combinations that include at least one wP administration, even as a booster dose, are sufficient to induce this broad effector response, thus highlighting its dominant imprint on the B cell profile. Finally, we describe the settlement of memory B cell populations in the lung following subcutaneous wP prime vaccination.

Authors

Viviana Valeri, Akhésa Sochon, Clara Cousu, Pascal Chappert, Damiana Lecoeuche, Pascal Blanc, Jean-Claude Weill, Claude-Agnès Reynaud

SARA suppresses myofibroblast precursor transdifferentiation in fibrogenesis in a mouse model of scleroderma

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Abstract

We previously reported that Smad Anchor for Receptor Activation (SARA) plays a critical role in maintaining epithelial cell phenotype. Here, we show that SARA suppresses myofibroblast precursor transdifferentiation in a mouse model of scleroderma. Mice overexpressing SARA specifically in PDGFRβ+ pericytes and pan-leukocytes (SARATg) developed significantly less skin fibrosis in response to bleomycin injection compared to wild-type littermates (SARAWT).Single cell RNASeq analysis of skin PDGFRβ+ cells implicated pericyte subsets assuming myofibroblast characteristics under fibrotic stimuli, and SARA overexpression blocked the transition. In addition, a cluster that expresses molecules associated with Th2 cells and macrophage activation was enriched in SARAWT, but not in SARATg mouse, after bleomycin treatment. Th2- specific Il-31 expression was increased in skin of the bleomycin-treated SARAWT mice, and scleroderma patients. Receptor-ligand analyses indicated that lymphocytes mediate pericyte transdifferentiation in SARAWT mice, while with SARA overexpression the myofibroblast activity of pericytes was suppressed. Together, these data suggest a novel crosstalk between myofibroblast precursors and immune cells in the pathogenesis of SSc, for which SARA plays a critical role.

Authors

Katia Corano-Scheri, Xiaoyan Liang, Vidhi Dalal, I. Caroline Le Poole, John Varga, Tomoko Hayashida

Iron accelerates Fusobacterium nucleatum-induced CCL8 expression in macrophages and is associated with colorectal cancer progression

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Abstract

Accumulating evidence suggests that high levels of Fusobacterium nucleatum (F. nucleatum) in colorectal tumor tissues can be associated with poor prognosis in patients with colorectal cancer (CRC); however, data regarding distinct prognostic subgroups in F. nucleatum-positive CRC remain limited. Herein, we demonstrated that high iron status was associated with a worse prognosis in CRC patients with F. nucleatum. Patients with CRC presenting elevated serum transferrin saturation exhibited preferential iron deposition in macrophages in the tumor microenvironment. In addition, F. nucleatum induced CCL8 expression in macrophages via the Toll-like receptor 4–nuclear factor-κB (NF-κB) signaling pathway, which was inhibited by iron deficiency. Mechanistically, iron attenuated the inhibitory phosphorylation of NF-κB p65 by activating serine/threonine phosphatases, augmenting tumor-promoting chemokine production in macrophages. Our observations indicate a key role for iron in modulating the NF-κB signaling pathway and suggest its prognostic potential as a determining factor for inter-patient heterogeneity in F. nucleatum-positive CRC.

Authors

Taishi Yamane, Yohei Kanamori, Hiroshi Sawayama, Hiromu Yano, Akihiro Nita, Yudai Ohta, Hironori Hinokuma, Ayato Maeda, Akiko Iwai, Takashi Matsumoto, Mayuko Shimoda, Mayumi Niimura, Shingo Usuki, Noriko Yasuda-Yoshihara, Masato Niwa, Yoshifumi Baba, Takatsugu Ishimoto, Yoshihiro Komohara, Tomohiro Sawa, Tasuku Hirayama, Hideo Baba, Toshiro Moroishi

Deficiency of inhibitory TLR4 homolog RP105 exacerbates fibrosis

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Abstract

Activation of Toll-like receptor 4 (TLR4) by its cognate damage-associated endogenous ligands (DAMPs) elicits potent profibrotic effects and myofibroblasts activation in systemic sclerosis (SSc), while genetic targeting of TLR4 or its DAMPs in mice accelerates fibrosis resolution. To prevent aberrant DAMP-TLR4 activity, a variety of negative regulators evolved to dampen the magnitude and duration of the signaling. These include radioprotective 105 KDa (RP105), a transmembrane TLR4 homolog that competitively inhibits DAMP recognition of TLR4, blocking TLR4 signaling in immune cells. The role of RP105 in TLR4-dependent fibrotic responses in SSc is unknown. Using unbiased transcriptome analysis of skin biopsies, we found that both TLR4 and its adaptor protein MD2 were elevated in SSc skin and significantly correlated with each other (r=0.54, p=0.0062). Expression of RP105 was negatively associated with myofibroblast differentiation in SSc (r=-0.53). Importantly, RP105-TLR4 association was reduced while TLR4- TLR4 showed strong association in SSc fibroblasts as shown by PLA assays. Moreover, RP105 adaptor MD1 expression was significantly reduced in SSc skin biopsies and explanted SSc skin fibroblasts. Exogenous RP105-MD1 abrogated, while loss of RP105 exaggerated, fibrotic cellular responses. Importantly, ablation of RP105 in mice was associated with augmented TLR4 signaling and aggravated skin fibrosis in complementary disease models. Thus, we identify RP105-MD1 as a novel cell-intrinsic negative regulator of TLR4-MD2-driven sustained fibroblast activation, representing a critical regulatory network governing the fibrotic process. Impaired RP105 function in SSc might contribute to persistence of progression of the disease.

Authors

Wenxia Wang, Swarna Bale, Bharath Yalavarthi, Priyanka Verma, Pei-Suen Tsou, Ken M. Calderone, Dibyendu Bhattacharyya, Gary J. Fisher, John Varga, Swati Bhattacharyya

Unraveling unique features of plasma cell clones in POEMS syndrome by single-cell analysis

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Abstract

POEMS syndrome is a rare monoclonal plasma cell disorder with unique symptoms distinct from other plasma cell neoplasms, including high serum VEGF levels. Since the prospective isolation of POEMS clones has not yet been successful, their real nature remains unclear. We herein performed the single-cell RNA sequencing of bone marrow plasma cells from patients with POEMS syndrome and identified POEMS clones that had immunoglobulin λ light chain (IGL) sequences (IGLV1-36, 40, 44, and 47) with amino acid changes specific to POEMS syndrome. The proportions of POEMS clones in plasma cells were markedly smaller (median: 12.9%) than in multiple myeloma (MM) (96–100%) and monoclonal gammopathy of undetermined significance (MGUS) patients (57–81%). Single-cell transcriptomes revealed that POEMS clones were CD19-negative, CD138-positive, and MHC class II-low, which allowed for their prospective isolation. POEMS clones expressed significantly lower levels of c-MYC and CCND1 than MM, accounting for their small size. VEGF mRNA was not up-regulated in POEMS clones, directly indicating that VEGF is not produced by POEMS clones. These results reveal unique features of POEMS clones and enhance our understanding of the pathogenesis of POEMS syndrome.

Authors

Yusuke Isshiki, Motohiko Oshima, Naoya Mimura, Kensuke Kayamori, Yurie Miyamoto-Nagai, Masahide Seki, Yaeko Nakajima-Takagi, Takashi Kanamori, Eisuke Iwamoto, Tomoya Muto, Shokichi Tsukamoto, Yusuke Takeda, Chikako Ohwada, Sonoko Misawa, Jun-ichiro Ikeda, Masashi Sanada, Satoshi Kuwabara, Yutaka Suzuki, Emiko Sakaida, Chiaki Nakaseko, Atsushi Iwama

Hyperglycemia exacerbates dengue virus infection by facilitating poly(A)-binding protein-mediated viral translation

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Abstract

Diabetes mellitus (DM) is highly comorbid with severe dengue diseases; however, the underlying mechanisms are unclear. DM patients display a 1.61-fold increased risk of developing dengue hemorrhagic fever. In search of host factors involved in DENV infection, this study utilizes high glucose (HG) treatment and shows that HG increases viral protein expression and virion release but has no effects on the early stages of viral infection. Following HG stimulation, DEN-Luc-transfected assay and cellular replicon-based assay display increased viral translation, while using the glucose uptake inhibitor phloretin blocks this effect. HG treatment increases the translational factor poly(A)-binding protein (PABP) in a glucose transporter-associated PI3K/AKT-regulated manner. Silencing PABP significantly decreases HG-prompted virion production. HG enhances the formation of the PABP-eIF4G complex, which is regulated by protein-disulfide isomerase. Hyperglycemia increases PABP expression, mortality, viral protein expression, and viral loads in streptozotocin-induced DM mice. Overall, hyperglycemic stress facilitates DENV infection by strengthening PABP-mediated viral translation.

Authors

Ting-Jing Shen, Chia-Ling Chen, Tsung-Ting Tsai, Ming-Kai Jhan, Chyi-Huey Bai, Yu-Chun Yen, Ching-Wen Tsai, Cheng-Yi Lee, Po-Chun Tseng, Chia-Yi Yu, Chiou-Feng Lin

Blockade of TGF-β signaling reactivates HIV-1/SIV reservoirs and immune responses in vivo

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Abstract

TGF-β plays a critical role in maintaining immune cells in a resting state by inhibiting cell activation and proliferation. Resting HIV-1 target cells represent the main cellular reservoir after long-term ART. We hypothesized that releasing cells from TGF-β-driven signaling would promote latency reversal. To test our hypothesis, we compared HIV-1 latency models with and without TGF-β and a TGF-β-Type-1 receptor (TGFBR1) inhibitor, galunisertib. We tested the effect of galunisertib in SIV-infected, ART-treated macaques by monitoring SIV-env expression via PET/CT using the Cu64-anti-gp120 Fab(7D3) probe, along with plasma and tissue viral loads (VL). Exogenous TGF-β reduced HIV-1 reactivation in U1 and ACH2 models. Galunisertib increased HIV-1 latency reversal ex vivo and in PBMC from HIV-1 infected, ART-treated aviremic donors. In vivo, oral galunisertib promoted increased total standardized uptake values (SUVtot) in PET/CT images in gut and lymph nodes of 5 out of 7 aviremic, long-term ART-treated, SIV-infected, macaques. This increase correlated with an increase in SIV-RNA in the gut. Two of the 7 animals also exhibited increases in pVL. Higher anti-SIV T cell responses and antibody titers were detected after galunisertib treatment. In summary, our data suggest that blocking TGF-β signaling simultaneously increases retroviral reactivation events and enhances anti-SIV immune responses.

Authors

Sadia Samer, Yanique Thomas, Mariluz Araínga, Crystal Carter, Lisa M. Shirreff, Muhammad S. Arif, Juan M. Avita, Ines Frank, Michael D. McRaven, Christopher T. Thuruthiyil, Veli B. Heybeli, Meegan R. Anderson, Benjamin Owen, Arsen Gaisin, Deepanwita Bose, Lacy M. Simons, Judd F. Hultquist, James Arthos, Claudia Cicala, Irini Sereti, Philip J. Santangelo, Ramon Lorenzo-Redondo, Thomas J. Hope, Francois Villinger, Elena Martinelli