Research Article
Abstract
Fibrosis is the final common pathway leading to end-stage chronic kidney disease (CKD). However, the function of protein palmitoylation in renal fibrosis and the underlying mechanisms remain unclear. In this study, we observed that expression of the palmitoyltransferase ZDHHC18 was significantly elevated in unilateral ureteral obstruction (UUO) and folic acid–induced (FA-induced) renal fibrosis mouse models and was significantly upregulated in fibrotic kidneys of patients with CKD. Functionally, tubule-specific deletion of ZDHHC18 attenuated tubular epithelial cells’ partial epithelial-mesenchymal transition (EMT) and then reduced the production of profibrotic cytokines and alleviated tubulointerstitial fibrosis. In contrast, ZDHHC18 overexpression exacerbated progressive renal fibrosis. Mechanistically, ZDHHC18 catalyzed the palmitoylation of HRAS, which was pivotal for its translocation to the plasma membrane and subsequent activation. HRAS palmitoylation promoted downstream phosphorylation of MEK/ERK and further activated Ras-responsive element–binding protein 1 (RREB1), enhancing SMAD binding to the Snai1 cis-regulatory regions. Taken together, our findings suggest that ZDHHC18 plays a crucial role in renal fibrogenesis and represents a potential therapeutic target for combating kidney fibrosis.
Authors
Di Lu, Gulibositan Aji, Guanyu Li, Yue Li, Wenlin Fang, Shuai Zhang, Ruiqi Yu, Sheng Jiang, Xia Gao, Yuhang Jiang, Qi Wang
Abstract
Oncostatin M (OSM) is a cytokine with the unique ability to interact with both the OSM receptor (OSMR) and the leukemia inhibitory factor receptor (LIFR). On the other hand, OSMR interacts with IL31RA to form the interleukin-31 receptor. This intricate network of cytokines and receptors makes it difficult to understand the specific function of OSM. While monoallelic loss-of-function (LoF) mutations in OSMR underlie autosomal dominant familial primary localized cutaneous amyloidosis, the in vivo consequences of human OSM deficiency have never been reported so far. Here, we identified 3 young individuals from a consanguineous family presenting with inherited severe bone marrow failure syndromes (IBMFS) characterized by profound anemia, thrombocytopenia, and neutropenia. Genetic analysis revealed a homozygous 1 base-pair insertion in the sequence of OSM associated with the disease. Structural and functional analyses showed that this variant causes a frameshift that replaces the C-terminal portion of OSM, which contains the FxxK motif that interacts with both OSMR and LIFR, with a neopeptide. The lack of detection and signaling of the mutant OSM suggests a LoF mutation. Analysis of zebrafish models further supported the role of the OSM/OSMR signaling in erythroid progenitor proliferation and neutrophil differentiation. Our study provides the previously uncharacterized and unexpectedly limited in vivo consequence of OSM deficiency in humans.
Authors
Alexandrine Garrigue, Laëtitia Kermasson, Sandrine Susini, Ingrid Fert, Christopher B. Mahony, Hanem Sadek, Sonia Luce, Myriam Chouteau, Marina Cavazzana, Emmanuelle Six, Marie-Caroline Le Bousse-Kerdilès, Adrienne Anginot, Jean-Baptiste Souraud, Valérie Cormier-Daire, Marjolaine Willems, Anne Sirvent, Jennifer Russello, Isabelle Callebaut, Isabelle André, Julien Y. Bertrand, Chantal Lagresle-Peyrou, Patrick Revy
Abstract
The cornerstone of functional cure for chronic hepatitis B (CHB) is hepatitis B surface antigen (HBsAg) loss from blood. HBsAg is encoded by covalently closed circular DNA (cccDNA) and HBV DNA integrated into the host genome (iDNA). Nucleos(t)ide analogs (NUCs), the mainstay of CHB treatment, rarely lead to HBsAg loss, which we hypothesized was due to continued iDNA transcription despite decreased cccDNA transcription. To test this, we applied a multiplex droplet digital PCR that identifies the dominant source of HBsAg mRNAs to 3,436 single cells from paired liver biopsies obtained from 10 people with CHB and HIV receiving NUCs. With increased NUC duration, cells producing HBsAg mRNAs shifted their transcription from chiefly cccDNA to chiefly iDNA. This shift was due to both a reduction in the number of cccDNA-containing cells and diminished cccDNA-derived transcription per cell; furthermore, it correlated with reduced detection of proteins deriving from cccDNA but not iDNA. Despite this shift in the primary source of HBsAg, rare cells remained with detectable cccDNA-derived transcription, suggesting a source for maintaining the replication cycle. Functional cure must address both iDNA and residual cccDNA transcription. Further research is required to understand the significance of HBsAg when chiefly derived from iDNA.
Authors
Maraake Taddese, Tanner Grudda, Giulia Belluccini, Mark Anderson, Gavin Cloherty, Hyon S. Hwang, Monika Mani, Che-Min Lo, Naomi Esrig, Mark S. Sulkowski, Richard K. Sterling, Yang Zhang, Ruy M. Ribeiro, David L. Thomas, Chloe L. Thio, Ashwin Balagopal
Abstract
Hypoxia is a major cause of pulmonary hypertension (PH) worldwide, and it is likely that interstitial pulmonary macrophages contribute to this vascular pathology. We observed in hypoxia-exposed mice an increase in resident interstitial macrophages, which expanded through proliferation and expressed the monocyte recruitment ligand CCL2. We also observed an increase in CCR2+ macrophages through recruitment, which express the protein thrombospondin-1, which functionally activates TGF-β to cause vascular disease. Blockade of monocyte recruitment with either CCL2-neutralizing antibody treatment or CCR2 deficiency in the bone marrow compartment suppressed hypoxic PH. These data were supported by analysis of plasma samples from humans who traveled from low (225 m) to high (3500 m) elevation, revealing an increase in thrombospondin-1 and TGF-β expression following ascent, which was blocked by dexamethasone prophylaxis. In the hypoxic mouse model, dexamethasone prophylaxis recapitulated these findings by mechanistically suppressing CCL2 expression and CCR2+ monocyte recruitment. These data suggest a pathologic cross talk between 2 discrete interstitial macrophage populations, which can be therapeutically targeted.
Authors
Rahul Kumar, Kevin Nolan, Biruk Kassa, Neha Chanana, Tsering Palmo, Kavita Sharma, Kanika Singh, Claudia Mickael, Dara Fonseca Balladares, Julia Nilsson, Amit Prabhakar, Aastha Mishra, Michael H. Lee, Linda Sanders, Sushil Kumar, Ari B. Molofsky, Kurt R. Stenmark, Dean Sheppard, Rubin M. Tuder, Mohit D. Gupta, Tashi Thinlas, Qadar Pasha, Brian B. Graham
Abstract
Constitutively active mutations of KRAS are prevalent in non–small cell lung cancer (NSCLC). However, the relationship between these mutations and resistance to platinum-based chemotherapy and the underlying mechanisms remain elusive. In this study, we demonstrate that KRAS mutants confer resistance to platinum in NSCLC. Mechanistically, KRAS mutants mediate platinum resistance in NSCLC cells by activating ERK/JNK signaling, which inhibits AlkB homolog 5 (ALKBH5) N6-methyladenosine (m6A) demethylase activity by regulating posttranslational modifications (PTMs) of ALKBH5. Consequently, the KRAS mutant leads to a global increase in m6A methylation of mRNAs, particularly damage-specific DNA-binding protein 2 (DDB2) and XPC, which are essential for nucleotide excision repair. This methylation stabilized the mRNA of these 2 genes, thus enhancing NSCLC cells’ capability to repair platinum-induced DNA damage and avoid apoptosis, thereby contributing to drug resistance. Furthermore, blocking KRAS-mutant–induced m6A methylation, either by overexpressing a SUMOylation-deficient mutant of ALKBH5 or by inhibiting methyltransferase-like 3 (METTL3) pharmacologically, significantly sensitizes KRAS-mutant NSCLC cells to platinum drugs in vitro and in vivo. Collectively, our study uncovers a mechanism that mediates KRAS-mutant–induced chemoresistance in NSCLC cells by activating DNA repair through the modulation of the ERK/JNK/ALKBH5 PTM-induced m6A modification in DNA damage repair–related genes.
Authors
Fang Yu, Shikan Zheng, Chunjie Yu, Sanhui Gao, Zuqi Shen, Rukiye Nar, Zhexin Liu, Shuang Huang, Lizi Wu, Tongjun Gu, Zhijian Qian
Abstract
Mammalian injury responses are predominantly characterized by fibrosis and scarring rather than functional regeneration. This limited regenerative capacity in mammals could reflect a loss of proregeneration programs or active suppression by genes functioning akin to tumor suppressors. To uncover programs governing regeneration in mammals, we screened transcripts in human participants following laser rejuvenation treatment and compared them with mice with enhanced wound-induced hair neogenesis (WIHN), a rare example of mammalian organogenesis. We found that Rnasel–/– mice exhibit an increased regenerative capacity, with elevated WIHN through enhanced IL-36α. Consistent with RNase L’s known role to stimulate caspase-1, we found that pharmacologic inhibition of caspases promoted regeneration in an IL-36–dependent manner in multiple epithelial tissues. We identified a negative feedback loop, where RNase L–activated caspase-1 restrains the proregenerative dsRNA-TLR3 signaling cascade through the cleavage of toll-like adaptor protein TRIF. Through integrated single-cell RNA-seq and spatial transcriptomic profiling, we confirmed OAS & IL-36 genes to be highly expressed at the site of wounding and elevated in Rnasel–/– mouse wounds. This work suggests that RNase L functions as a regeneration repressor gene, in a functional trade off that tempers immune hyperactivation during viral infection at the cost of inhibiting regeneration.
Authors
Charles S. Kirby, Nasif Islam, Eric Wier, Martin P. Alphonse, Evan Sweren, Gaofeng Wang, Haiyun Liu, Dongwon Kim, Ang Li, Sam S. Lee, Andrew M. Overmiller, Yingchao Xue, Sashank Reddy, Nathan K. Archer, Lloyd S. Miller, Jianshi Yu, Weiliang Huang, Jace W. Jones, Sooah Kim, Maureen A. Kane, Robert H. Silverman, Luis A. Garza
Abstract
Fibrosis of the lower abdominal muscle (LAM) contributes to muscle weakening and inguinal hernia formation, an ailment that affects a noteworthy 50% of men by age 75 and necessitates surgical correction as the singular therapy. Despite its prevalence, the mechanisms driving LAM fibrosis and hernia development remain poorly understood. Using a humanized mouse model that replicates the elevated skeletal muscle tissue estrogen concentrations seen in aging men, we identified estrogen receptor-α (ESR1) as a key driver of LAM fibroblast proliferation, extracellular matrix deposition, and hernia formation. Fibroblast-specific ESR1 ablation effectively prevented muscle fibrosis and herniation, while pharmacological ESR1 inhibition with fulvestrant reversed hernias and restored normal muscle architecture. Multiomics analyses of in vitro LAM fibroblasts from humanized mice unveiled an estrogen/ESR1-mediated activation of a distinct profibrotic cistrome and gene expression signature, concordant with observations in inguinal hernia tissues in human males. Our findings hold significant promise for prospective medical interventions targeting fibrotic conditions and present non-surgical avenues for addressing inguinal hernias.
Authors
Tanvi Potluri, Tianming You, Ping Yin, John Coon V, Jonah J. Stulberg, Yang Dai, David J. Escobar, Richard L. Lieber, Hong Zhao, Serdar E. Bulun
Abstract
Mycobacterium tuberculosis causes human tuberculosis (TB). As mycobacteria are protected by a thick lipid cell wall, humans have developed immune responses against diverse mycobacterial lipids. Most of these immunostimulatory lipids are known as adjuvants acting through innate immune receptors, such as C-type lectin receptors. Although a few mycobacterial lipid antigens activate unconventional T cells, the antigenicity of most adjuvantic lipids is unknown. Here, we identified that trehalose monomycolate (TMM), an abundant mycobacterial adjuvant, activated human T cells bearing a unique αβ T cell receptor (αβTCR). This recognition was restricted by CD1b, a monomorphic antigen-presenting molecule conserved in primates but not mice. Single-cell TCR-RNA-Seq using newly established CD1b-TMM tetramers revealed that TMM-specific T cells were present as CD4+ effector memory T cells in the periphery of uninfected donors but expressed IFN-γ, TNF, and anti-mycobacterial effectors upon TMM stimulation. TMM-specific T cells were detected in cord blood and PBMCs of donors without bacillus Calmette-Guérin vaccination but were expanded in patients with active TB. A cryo-electron microscopy study of CD1b-TMM-TCR complexes revealed unique antigen recognition by conserved features of TCRs, positively charged CDR3α, and long CDR3β regions. These results indicate that humans have a commonly shared and preformed CD4+ T cell subset recognizing a typical mycobacterial adjuvant as an antigen. Furthermore, the dual role of TMM justifies reconsideration of the mechanism of action of adjuvants.
Authors
Yuki Sakai, Minori Asa, Mika Hirose, Wakana Kusuhara, Nagatoshi Fujiwara, Hiroto Tamashima, Takahiro Ikazaki, Shiori Oka, Kota Kuraba, Kentaro Tanaka, Takashi Yoshiyama, Masamichi Nagae, Yoshihiko Hoshino, Daisuke Motooka, Ildiko Van Rhijn, Xiuyuan Lu, Eri Ishikawa, D. Branch Moody, Takayuki Kato, Shinsuke Inuki, Go Hirai, Sho Yamasaki
Abstract
Viral mimicry refers to the activation of innate antiviral immune responses due to the induction of endogenous retroelements (REs). Viral mimicry augments antitumor immune responses and sensitizes solid tumors to immunotherapy. Here, we found that targeting what we believe to be a novel, master epigenetic regulator, Zinc Finger Protein 638 (ZNF638), induces viral mimicry in glioblastoma (GBM) preclinical models and potentiates immune checkpoint inhibition (ICI). ZNF638 recruits the HUSH complex, which precipitates repressive H3K9me3 marks on endogenous REs. In GBM, ZNF638 is associated with marked locoregional immunosuppressive transcriptional signatures, reduced endogenous RE expression, and poor immune cell infiltration. Targeting ZNF638 decreased H3K9 trimethylation, increased REs, and activated intracellular dsRNA signaling cascades. Furthermore, ZNF638 knockdown upregulated antiviral immune programs and significantly increased PD-L1 immune checkpoint expression in diverse GBM models. Importantly, targeting ZNF638 sensitized mice to ICI in syngeneic murine orthotopic models through innate IFN signaling. This response was recapitulated in recurrent GBM (rGBM) samples with radiographic responses to checkpoint inhibition with widely increased expression of dsRNA, PD-L1, and perivascular CD8 cell infiltration, suggesting that dsRNA signaling may mediate response to immunotherapy. Finally, low ZNF638 expression was a biomarker of clinical response to ICI and improved survival in patients with rGBM and patients with melanoma. Our findings suggest that ZNF638 could serve as a target to potentiate immunotherapy in gliomas.
Authors
Deepa Seetharam, Jay Chandar, Christian K. Ramsoomair, Jelisah F. Desgraves, Alexandra Alvarado Medina, Anna Jane Hudson, Ava Amidei, Jesus R. Castro, Vaidya Govindarajan, Sarah Wang, Yong Zhang, Adam M. Sonabend, Mynor J. Mendez Valdez, Dragan Maric, Vasundara Govindarajan, Sarah R. Rivas, Victor M. Lu, Ritika Tiwari, Nima Sharifi, Emmanuel Thomas, Marcus Alexander, Catherine DeMarino, Kory Johnson, Macarena I. De La Fuente, Ruham Alshiekh Nasany, Teresa Maria Rosaria Noviello, Michael E. Ivan, Ricardo J. Komotar, Antonio Iavarone, Avindra Nath, John Heiss, Michele Ceccarelli, Katherine B. Chiappinelli, Maria E. Figueroa, Defne Bayik, Ashish H. Shah
Abstract
Rheumatoid arthritis (RA) is a systemic autoimmune disease currently with no universally highly effective prevention strategies. Identifying pathogenic immune phenotypes in at-risk populations prior to clinical onset is crucial to establishing effective prevention strategies. Here, we applied multimodal single-cell technologies (mass cytometry and CITE-Seq) to characterize the immunophenotypes in blood from at-risk individuals (ARIs) identified through the presence of serum antibodies against citrullinated protein antigens (ACPAs) and/or first-degree relative (FDR) status, as compared with patients with established RA and people in a healthy control group. We identified significant cell expansions in ARIs compared with controls, including CCR2+CD4+ T cells, T peripheral helper (Tph) cells, type 1 T helper cells, and CXCR5+CD8+ T cells. We also found that CD15+ classical monocytes were specifically expanded in ACPA-negative FDRs, and an activated PAX5lo naive B cell population was expanded in ACPA-positive FDRs. Further, we uncovered the molecular phenotype of the CCR2+CD4+ T cells, expressing high levels of Th17- and Th22-related signature transcripts including CCR6, IL23R, KLRB1, CD96, and IL22. Our integrated study provides a promising approach to identify targets to improve prevention strategy development for RA.
Authors
Jun Inamo, Joshua Keegan, Alec Griffith, Tusharkanti Ghosh, Alice Horisberger, Kaitlyn Howard, John F. Pulford, Ekaterina Murzin, Brandon Hancock, Salina T. Dominguez, Miranda G. Gurra, Siddarth Gurajala, Anna Helena Jonsson, Jennifer A. Seifert, Marie L. Feser, Jill M. Norris, Ye Cao, William Apruzzese, S. Louis Bridges, Vivian P. Bykerk, Susan Goodman, Laura T. Donlin, Gary S. Firestein, Joan M. Bathon, Laura B. Hughes, Andrew Filer, Costantino Pitzalis, Jennifer H. Anolik, Larry Moreland, Nir Hacohen, Joel M. Guthridge, Judith A. James, Carla M. Cuda, Harris Perlman, Michael B. Brenner, Soumya Raychaudhuri, Jeffrey A. Sparks, The Accelerating Medicines Partnership RA/SLE Network, V. Michael Holers, Kevin D. Deane, James Lederer, Deepak A. Rao, Fan Zhang
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ISSN: 0021-9738 (print), 1558-8238 (online)