While T cells are important for the pathogenesis of systemic lupus erythematosus (SLE) and lupus nephritis, little is known about how T cells function after infiltrating the kidney. The current paradigm suggests that kidney infiltrating T cells (KITs) are activated effector cells contributing to tissue damage and ultimately organ failure. Herein, we demonstrate that the majority of CD4+ and CD8+ KITs in three murine lupus models are not effector cells, as hypothesized, but rather expressed multiple inhibitory receptors and proved highly dysfunctional with reduced cytokine production and proliferative capacity. Mechanistically this was linked directly to metabolic and specifically mitochondrial dysfunction. This was driven by the expression of an “exhausted” transcriptional signature. Our data thus reveal that the tissue parenchyma has the capability to suppress T cell responses and limit damage to self. These findings open novel avenues for the treatment of autoimmunity based on selectively exploiting the exhausted phenotype of tissue-infiltrating T cells.
Jeremy S. Tilstra, Lyndsay Avery, Ashley V. Menk, Rachael A. Gordon, Shuchi Smita, Lawrence P. Kane, Maria Chikina, Greg M. Delgoffe, Mark J. Shlomchik
Regulatory T-cells (Treg) are critical for maintaining immune homeostasis. However, current Treg immunotherapies do not optimally treat inflammatory diseases in patients. Understanding the cellular processes that control Treg function may allow for the augmentation of therapeutic efficacy. In contrast to activated conventional T-cells, where protein kinase C-θ (PKC-θ) localizes to the contact-point between T-cells and antigen-presenting cells, in human and mouse Treg, PKC-θ localizes to the opposite end of the cell in the distal pole complex (DPC). Here, using a phosphoproteomic screen, we identified the intermediate filament vimentin as a PKC-θ phospho-target and show that vimentin forms a DPC superstructure on which PKC-θ accumulates. Treatment of mouse Treg with either a clinically relevant PKC-θ inhibitor or vimentin siRNA disrupted vimentin and enhanced Treg metabolic and suppressive activity. Moreover, vimentin-disrupted mouse Treg were significantly better than controls in suppressing alloreactive T-cell priming in graft-versus-host disease, and graft-versus-host disease lethality, using a complete MHC mismatch mouse model of acute graft-versus-host disease (C57BL/6 donor in to BALB/c host). Interestingly, vimentin disruption augmented suppressor function of PKC-θ-deficient mouse Treg. This suggests that enhanced Treg activity after PKC-θ inhibition is secondary to effects on vimentin, not just PKC-θ kinase activity inhibition. Our data demonstrated that vimentin is a key metabolic and functional controller of Treg activity, and provide proof-of-principle that disrupting vimentin is a feasible, translationally relevant method to enhance Treg potency.
Cameron McDonald-Hyman, James T. Muller, Michael Loschi, Govindarajan Thangavelu, Asim Saha, Sudha Kumari, Dawn K. Reichenbach, Michelle J. Smith, Guoan Zhang, Brent H. Koehn, Jiqiang Lin, Jason S. Mitchell, Brian T. Fife, Angela Panoskaltsis-Mortari, Colby J. Feser, Andrew Kemal Kirchmeier, Mark J. Osborn, Keli L. Hippen, Ameeta Kelekar, Jonathan S. Serody, Laurence A. Turka, David H. Munn, Hongbo Chi, Thomas A. Neubert, Michael L. Dustin, Bruce R. Blazar
Previous findings showed that in mice, complete knockout of activity-dependent neuroprotective protein (ADNP) abolishes brain formation, while haploinsufficiency (Adnp+/–) causes cognitive impairments. We hypothesized that mutations in ADNP lead to a developmental/autistic syndrome in children. Indeed, recent phenotypic characterization of children harboring ADNP mutations (ADNP syndrome children) revealed global developmental delays and intellectual disabilities, including speech and motor dysfunctions. Mechanistically, ADNP includes a SIP motif embedded in the ADNP-derived snippet, drug candidate NAP (NAPVSIPQ also known as CP201), which binds to microtubule end binding protein 3, essential for dendritic spine formation. Here, we established a unique neuronal membrane tagged green fluorescent protein expressing Adnp+/– mouse line allowing in vivo synaptic pathology quantification. We discovered that Adnp deficiency reduced dendritic spine density and altered synaptic gene expression, both of which were partly ameliorated by NAP treatment. Adnp+/– mice further exhibited global developmental delays, vocalization impediments, gait/motor dysfunctions and social/object memory impairments, all partially reversed by daily NAP administration (systemic/nasal). In conclusion, we now connected ADNP-related synaptic pathology to developmental/behavioral outcomes, establishing NAP in vivo target engagement and identifying potential biomarkers. Together, these studies pave the path toward clinical development of NAP (CP201) in the ADNP syndrome.
Gal Hacohen-Kleiman, Shlomo Sragovich, Gidon Karmon, Andy Y. L. Gao, Iris Grigg, Metsada Pasmanik-Chor, Albert Le, Vlasta Korenková, R. Anne McKinney, Illana Gozes
B cells are increasingly recognised to play an important role in the ongoing control of hepatitis B virus (HBV). The development of antibodies against the viral surface antigen (HBsAg) constitutes the hallmark of resolution of acute infection and is a therapeutic goal for functional cure of chronic HBV (CHB). We characterised B cells directly ex vivo from the blood and liver of patients with CHB to investigate constraints on their antiviral potential. Unexpectedly, we found that HBsAg-specific B cells persisted in the blood and liver of many patients with CHB and were enriched for T-bet, a signature of antiviral potential in B cells. However purified, differentiated HBsAg-specific B cells from patients with CHB had defective antibody production, consistent with undetectable anti-HBs antibodies in vivo. HBsAg-specific and global B cells had an accumulation of CD21–CD27– atypical memory B cells (atMBC) with high expression of inhibitory receptors including PD-1. These atMBC demonstrated altered signalling, homing, differentiation into antibody-producing cells, survival and antiviral/pro-inflammatory cytokine production, that could be partially rescued by PD-1 blockade. Analysis of B cells within healthy and HBV-infected livers implicated the combination of this tolerogenic niche and HBV infection in driving PD-1hiatMBC and impairing B cell immunity.
Alice R. Burton, Laura J. Pallett, Laura E. McCoy, Kornelija Suveizdyte, Oliver E. Amin, Leo Swadling, Elena Alberts, Brian R. Davidson, Patrick T.F. Kennedy, Upkar S. Gill, Claudia Mauri, Paul A. Blair, Nadege Pelletier, Mala K. Maini
Chronic HBV (CHB) infection suppresses virus-specific T cells, but its impact on humoral immunity has been poorly analyzed. Here, we developed a dual staining method, which utilizes HBsAg labelled with fluorochromes as “baits”, for specific ex vivo detection of HBsAg-specific B cells and analysis of their quantity, function and phenotype. We studied healthy vaccinated subjects (n=18) and patients with resolved (n=21), acute (n=11) or chronic (n=96) HBV infection and observed that frequencies of circulating HBsAg-specific B cells are independent of the HBV infection status. In contrast, serum HBsAg presence affects function and phenotype of HBsAg-specific B cells that were unable to mature in vitro into antibody-secreting cells and displayed an increased expression of markers linked to hyperactivation (CD21low) and exhaustion (PD-1). Importantly, B cell alterations were not limited to HBsAg-specific B cells but affected the global B cell population. HBsAg-specific B cell maturation could be partially restored by a method involving the combination of IL-2, IL-21 and CD40L-expressing feeder cells, and further boosted by addition of anti-PD-1 antibodies.In conclusion, HBV infection has a marked impact on global and HBV-specific humoral immunity, yet HBsAg-specific B cells are amenable to a partial rescue by B cell maturing cytokines and PD-1 blockade.
Loghman Salimzadeh, Nina Le Bert, Charles-A. Dutertre, Upkar S. Gill, Evan W. Newell, Christian Frey, Magdeleine Hung, Nikolai Novikov, Simon Fletcher, Patrick T.F. Kennedy, Antonio Bertoletti
Zika virus (ZIKV) is a teratogenic mosquito-borne flavivirus which can be sexually transmitted from man to woman. High viral loads and prolonged viral shedding in semen suggest that ZIKV replicates within the human male genital tract, but its target organs are unknown. Using ex vivo infection of organotypic cultures, we demonstrated here that ZIKV replicates in human testicular tissue and infects a broad range of cell types, including germ cells, which we also identified as infected in the semen from ZIKV-infected donors. ZIKV had no major deleterious effect on the morphology and hormonal production of the human testis explants. Infection induced a broad antiviral response but no interferon up-regulation and minimal pro-inflammatory response in testis explants, with no cytopathic effect. Finally, we studied ZIKV infection in mouse testis, and compared it to human infection. This study provides key insights into how ZIKV may persist in semen and alter semen parameters, as well as a valuable tool for testing antiviral agents.
Giulia Matusali, Laurent Houzet, Anne-Pascale Satie, Dominique Mahé, Florence Aubry, Thérèse Couderc, Julie Frouard, Salomé Bourgeau, Karim Bensalah, Sylvain Lavoué, Guillaume Joguet, Louis Bujan, André Cabié, Gleide F. Avelar, Marc Lecuit, Anna Le Tortorec, Nathalie Dejucq-Rainsford
Prostate cancer is an androgen-dependent disease subject to interactions between the tumor epithelia and its microenvironment. Here, we found epigenetic changes in cancer-associated prostatic fibroblasts (CAF) initiated a cascade of stromal-epithelial interactions. This facilitated lethal prostate cancer growth and development of resistance to androgen signaling deprivation therapy (ADT). We identified that a Ras inhibitor, RASAL3, is epigenetically silenced in human prostatic CAF, leading to oncogenic Ras activity driving macropinocytosis-mediated glutamine synthesis. Interestingly, ADT further promoted RASAL3 epigenetic silencing and glutamine secretion by prostatic fibroblasts. In a orthotopic xenograft model, subsequent inhibition of macropinocytosis and glutamine transport resulted in antitumor effects. Stromal glutamine served as a source of energy through anaplerosis and as a mediator of neuroendocrine differentiation for prostate adenocarcinoma. Antagonizing the uptake of glutamine restored sensitivity to ADT in a castrate resistant xenograft model. In validating these findings, we found that prostate cancer patients on ADT with therapeutic resistance had elevated blood glutamine levels compared to those with therapeutically responsive disease (odds ratio = 7.451, P = 0.02). Identification of epigenetic regulation of RAS activity in prostatic CAF revealed RASAL3 as a sensor for metabolic and neuroendocrine reprogramming in prostate cancer patients failing ADT.
Rajeev Mishra, Subhash Haldar, Veronica Placencio, Anisha Madhav, Krizia Rohena-Rivera, Priyanka Agarwal, Frank Duong, Bryan Angara, Manisha Tripathi, Zhenqiu Liu, Roberta A. Gottlieb, Shawn Wagner, Edwin M. Posadas, Neil A. Bhowmick
Movement of circulating fatty acids (FAs) to parenchymal cells requires their transfer across the endothelial cell (EC) barrier. The multi-ligand receptor cluster of differentiation 36 (CD36) facilitates tissue FA uptake and is expressed in ECs and parenchymal cells such as myocytes and adipocytes. Whether tissue uptake of FAs is dependent on EC or parenchymal cell CD36, or both, is unknown. Using a cell-specific deletion approach, we show that EC, but not parenchymal cell CD36 deletion increased fasting plasma FAs and postprandial triglycerides. EC-Cd36 knockout mice had reduced uptake of radiolabeled long chain FAs into heart, skeletal muscle, and brown adipose tissue; these uptake studies were replicated using [11C]palmitate PET scans. High fat diet-fed EC-CD36 deficient mice had improved glucose tolerance and insulin sensitivity. Both EC and cardiomyocyte (CM) deletion of CD36 reduced heart lipid droplet accumulation after fasting, but CM deletion did not affect heart glucose or FA uptake. Heart expression of several genes modulating glucose metabolism and insulin action increased with EC-CD36 deletion, but decreased with CM deletion. In conclusion, EC CD36 acts as a gatekeeper for parenchymal cell FA uptake, with important downstream effects on glucose utilization and insulin action.
Ni-Huiping Son, Debapriya Basu, Dmitri Samovski, Terri A. Pietka, Vivek S. Peche, Florian Willecke, Xiang Fang, Shui-Qing Yu, Diego Scerbo, Hye Rim Chang, Fei Sun, Svetlana Bagdasarov, Konstantinos Drosatos, Steve T. Yeh, Adam E. Mullick, Kooresh I. Shoghi, Namrata Gumaste, KyeongJin Kim, Lesley-Ann M. Huggins, Tenzin Lhakhang, Nada A. Abumrad, Ira J. Goldberg
JAK2-V617F-positive chronic myeloproliferative neoplasia (CMN) is marked by dysfunction of integrins and adhesion molecules expressed on platelets, erythrocytes and leukocytes. However, the mechanism by which the two major leukocyte integrin chains, β1 and β2, mediate CMN pathophysiology remained unclear. β1 (α4β1; VLA-4) and β2 (αLβ2; LFA-1) integrins are essential regulators for attachment of leukocytes to endothelial cells. We here show enhanced adhesion of granulocytes from JAK2+/VF knock-in mice to vascular cell adhesion molecule 1 (VCAM1) and intercellular adhesion molecule 1 (ICAM1) coated surfaces. Soluble VCAM1 and ICAM1 ligand binding assays revealed increased affinity of β1 and β2 integrins for their respective ligands. For β1 integrins, this correlated with a structural change from the low to the high affinity conformation induced by JAK2-V617F. JAK2-V617F triggers constitutive activation of the integrin inside-out signaling molecule Rap1 resulting in translocation towards the cell membrane. Employing a venous thrombosis model, we demonstrate that neutralizing anti-VLA4 and anti-β2 integrin antibodies suppress pathologic thrombosis as observed in JAK2+/VF mice. In addition, aberrant homing of JAK2+/VF leukocytes to the spleen is inhibited by neutralizing anti-β2 antibodies and by pharmacologic inhibition of Rap1. Thus, our findings identify a cross talk between JAK2-V617F and integrin activation promoting pathologic thrombosis and abnormal trafficking of leukocytes to the spleen. .
Bärbel Edelmann, Nibedita Gupta, Tina M. Schnöder, Anja M. Oelschlegel, Khurrum Shahzad, Jürgen Goldschmidt, Lars Philipsen, Sönke Weinert, Aniket Ghosh, Felix C. Saalfeld, Subbaiah Chary Nimmagadda, Peter Müller, Rüdiger C. Braun-Dullaeus, Juliane Mohr, Denise Wolleschak, Stefanie Kliche, Holger Amthauer, Florian H. Heidel, Burkhart Schraven, Berend Isermann, Andreas Müller, Thomas Fischer
Oxidative stress is an underlying component of acute and chronic kidney disease. Apoptosis signal-regulating kinase 1 (ASK1) is a widely expressed redox-sensitive serine threonine kinase that activates p38 and c-Jun N-terminal kinase (JNK) mitogen-activated protein kinase kinases, and induces apoptotic, inflammatory, and fibrotic signaling in settings of oxidative stress. Herein, we describe the discovery and characterization of a potent and selective small molecule inhibitor of ASK1, GS-444217, and demonstrate the therapeutic potential of ASK1 inhibition to reduce kidney injury and fibrosis. Activation of the ASK1 pathway in glomerular and tubular compartments was confirmed in renal biopsies from patients with diabetic kidney disease (DKD) and was decreased by GS-444217 in several rodent models of kidney injury and fibrosis that collectively represented the hallmarks of DKD pathology. Treatment with GS-444217 reduced progressive inflammation and fibrosis in the kidney and halted decline of glomerular filtration rate. Combination of GS-444217 with enalapril, an angiotensin-converting enzyme inhibitor, led to a greater reduction in proteinuria and regression of glomerulosclerosis. These results identify ASK1 as an important target for renal disease and support the clinical development of an ASK1 inhibitor for the treatment of diabetic kidney disease.
John T. Liles, Britton K. Corkey, Gregory T. Notte, Grant Budas, Eric B. Lansdon, Ford Hinojosa-Kirschenbaum, Shawn S. Badal, Michael Lee, Brian E. Schultz, Sarah Wise, Swetha Pendem, Michael Graupe, Laurie Castonguay, Keith A. Koch, Melanie H. Wong, Giuseppe A. Papalia, Dorothy M. French, Theodore Sullivan, Erik G. Huntzicker, Frank Y. Ma, David J. Nikolic-Paterson, Tareq Altuhaifi, Haichun Yang, Agnes B. Fogo, David G. Breckenridge
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