Research Article
Abstract
Resistance to HIF-2α inhibitors such as belzutifan underscores the need to better understand how HIF-2α is transcriptionally regulated in clear cell renal cell carcinoma (ccRCC). Here, we uncover a cytokine-driven enhancer mechanism that sustains HIF-2α expression through the JAK1/STAT3 signaling pathway. Using a genome-wide CRISPR screen in von Hippel–Lindau–deficient (VHL-deficient) ccRCC cells, we identified SOCS3 as a key negative regulator of HIF-2α. Mechanistically, loss of SOCS3 activates JAK1/STAT3 signaling, leading to the recruitment of STAT3 to distal enhancers upstream of endothelial PAS domain-containing protein (EPAS1) that physically loop to its promoter to drive HIF-2α transcription. This cytokine-enhancer circuit was recapitulated in samples from patients with ccRCC and functionally validated using CRISPR interference (CRISPRi), which disrupted enhancer-promoter looping and reduced tumor growth in HIF-2α–dependent models. SOCS3 overexpression or pharmacologic inhibition of JAK1/STAT3 markedly suppressed HIF-2α expression and tumor progression both in vitro and in vivo. Unlike prior studies focusing on VHL/HIF occupancy–driven enhancer activation, this work defines a trans-acting cytokine–JAK1/STAT3 pathway that transcriptionally controls EPAS1. Together, these findings reveal a targetable enhancer mechanism that sustains HIF-2α expression and suggest that combined inhibition of JAK1/STAT3 and HIF-2α may overcome therapeutic resistance in kidney cancer.
Authors
Jun Fang, Jeremy M. Simon, Tao Wang, Yunpeng Gao, Xianju Bi, Lianxin Hu, Chengheng Liao, Cheng Zhang, Yayoi Adachi, Jin Zhou, Hongyi Liu, Qian Liang, James A. Nathan, Ram Mani, James Brugarolas, Qing Zhang
Abstract
Glioblastoma (GBM) is a highly aggressive brain tumor characterized by extensive crosstalk between glioblastoma stem cells (GSCs) and immunosuppressive microglia, with our previous work identifying CLOCK and TFPI2 as key regulators of this interaction. Here, we uncover a ‘symbiotic exclusivity’ pattern between CLOCK and TFPI2, showing that, despite mutually exclusive amplifications, they sustain symbiotic regulatory interactions in GBM. The CLOCK-BMAL1 complex transcriptionally upregulates TFPI2, while TFPI2-driven hypoxia inducible factor 1 α (HIF-1α) signaling activates nuclear factor k B (NF-kB) P65 to upregulate the CLOCK-BMAL1 complex, creating a positive feedback loop to promote stemness, immunosuppression, and tumor progression. Disrupting the CLOCK-TFPI2 interplay through dual inhibition of their downstream effectors reduces GSC stemness and immunosuppressive microglia, activates antitumor immunity, and synergizes with anti-PD1 therapy to achieve complete tumor regression in 50%–62.5% of tumor-bearing mice. This study uncovers a promising therapeutic strategy for a broader subset of patients with GBM with high expression of either CLOCK or TFPI2, and provides a framework for identifying ‘symbiotic exclusivity’ genes in cancer.
Authors
Fei Zhou, Lizhi Pang, Yang Liu, Fatima Khan, Peiwen Chen
Abstract
Airway mucus clearance from the lungs occurs by 2 widely recognized mechanisms: cilia-mediated clearance and high-velocity airflow-mediated cough clearance. However, a potentially important third mechanism of mucus clearance, referred to as cilia-independent gas–liquid transport (GLT), was proposed based on in vitro model systems to occur during normal tidal breathing but has largely been overlooked. We conducted in vitro and in vivo studies to investigate the role of tidal breathing airflow rates in mucus clearance. An in vitro airway culture bead-tracking model demonstrated airflow-dependent mucus transport at tidal breathing flow rates. As with other modes of mucus clearance, GLT was critically dependent on mucus concentration. In vivo studies in cilial beat-deficient mice demonstrated that GLT-mediated mucus clearance occurs during tidal breathing in the absence of cough, and the rate of GLT mucus clearance was dependent on breathing frequency and body orientation. These studies demonstrated that GLT is a third mechanism of mucus clearance and likely represents a significant mode of clearance in persons with cilial dysfunction. These findings indicate that increasing breathing rates through exercise, using mucus rehydrating agents or mucolytics, or combining these approaches may restore clinically and physiologically meaningful airway clearance in these patients.
Authors
Siddharth K. Shenoy, Mark Gutay, Ian Brown, Troy D. Rogers, Kane Banner, Nico Olegario, Nicholas Griffin, Henry P. Goodell, Bryan Yoder, David S. Lalush, David A. Edwards, Richard C. Boucher, Barbara R. Grubb, Brian Button
Abstract
Cilia are cellular organelles that extrude from the surface of various cell types, serving either sensory or motile functions. Retinitis pigmentosa GTPase regulator (RPGR) variants affect both photoreceptor sensory cilia and airway motile cilia, leading to retinitis pigmentosa (RP) and primary ciliary dyskinesia (PCD), respectively. Not all patients develop PCD, and it remains unclear which RPGR variants predispose patients to PCD. Here, we leverage 2D organoids, super-resolution microscopy, and live-cell imaging to characterize the multiciliated cells (MCCs) from patients with different RPGR variants and CRISPR-modified RPGR KO MCCs. We demonstrate that MCCs with RPGR variants have reduced ciliation, shorter cilia, impaired cilia beat, or cilia beat incoordination, potentially resulting in compromised mucociliary clearance and lung diseases. Moreover, we show that RPGR regulates motile cilia through interfering with F-actin dynamics, evidenced by the undissolved F-actin meshwork in RPGR-deficient MCCs, and the defects can be ameliorated with either latrunculin A or Y27632 treatment. Though PCD was observed only in patients with variants that affect both isoforms, patients with RPGRORF15 variants also had cilia and airway anomalies. All RPGR variants affected motile cilia in some way, and the mechanisms involved the accumulation of apical F-actin.
Authors
Yang Wu, Erika Tavares, Binrun Liang, Wallace B. Wee, Vito Mennella, Han-Chao Feng, Jiaying Cao, Pui Yee Wong, Jiayi Zheng, Mu He, Kirk AJ Stephenson, Liran Hanan Hochma, Janice Min Li, Nan-Peng Chen, Sharon D. Dell, Elise Heon, Zhen Liu
Abstract
Stimulant medications are widely prescribed for attention deficit hyperactivity disorder (ADHD) and have significant abuse liability. Here, we show that, consistent with clinical data, female mice exhibited enhanced behavioral sensitivity to stimulants, and we define sex- and hormone-dependent adaptations in the dopamine system that contributed to these effects. Single-nucleus RNA-seq of ventral tegmental area dopamine neurons revealed that projections to the nucleus accumbens (NAc) core, compared with other projection populations, were a hub of sexually dimorphic gene expression, including transcripts regulating dopamine synthesis, and transport. These molecular differences coincided with enhanced dopamine release and clearance in female mice, particularly during phases of the estrous cycle when estradiol levels were high. The stimulants amphetamine (a releaser) and methylphenidate (a reuptake inhibitor) more effectively increased dopamine levels in female mice under certain conditions. However, amphetamine showed more robust hormone-sensitive regulation, with potency reduced by ovariectomy and restored by direct estradiol replacement in the NAc core. Together, the findings indicate that even within a drug class, drugs with different mechanisms of action can leverage different aspects of sexually dimorphic dopamine function. This distinction highlights the notion that sex differences are not uniform but can be differentially sensitive to drug pharmacology.
Authors
Brooke A. Christensen, Jennifer Tat, Michael Z. Leonard, Soren D. Emerson, Shemuel Roberts, Eleanor B. Holmgren, Ainoa Konomi-Pilkati, Hannah B. Reiley, Devan M. Gomez, Lin Zheng, Hye Jean Yoon, Sofia H. Lago, Abigail L. Carr, Lillian J. Brady, Maxime Chevée, Erin S. Calipari
Abstract
VPS13A is an intracellular lipid transfer protein comprising more than 3,000 amino acids. Mutations in human VPS13A cause VPS13A disease, a neurodegenerative disorder that affects movement and cognition. VPS13A forms a complex with the membrane protein XK to mediate ATP-induced phospholipid scrambling in the plasma membrane. Here, we established a mouse cell system expressing full-length mouse VPS13A and examined its interaction with XK. Mutational analysis revealed that VPS13A binds to XK through a C-terminal β-strand that interacts with a β-hairpin in the central region of XK, an interaction essential for scramblase activity. The XK paralog XKR2, which contains a similar β-hairpin structure, also associates with VPS13A and supports phospholipid scrambling. We analyzed 10 mouse VPS13A variants corresponding to human patient mutations and classified them into 4 groups: (a) L67P, I90K, and W2453R, which showed reduced expression; (b) A1091P and M3080R, which were normally expressed but lacked scramblase activity; (c) S1446P, Q2689H, Y2713C, and R3084H, which modestly impaired expression or activity; and (d) I2763R, which altered cell size and disrupted ER independently of XK. These findings define the VPS13A–XK interaction interface, clarify the functional impact of disease-causing mutations, and reveal an unexpected gain-of-function mutation of a VPS13A variant.
Authors
Xing Lin, Yuta Ryoden, Chigure Suzuki, Hiroyuki Ishikawa, Takaharu Sakuragi, Yasuo Uchiyama, Shigekazu Nagata
Abstract
Crimean-Congo hemorrhagic fever virus (CCHFV) is an emerging arboviral and zoonotic bunyavirus. CCHFV can infect livestock, wild animals, and humans. Here, we report the isolation of a panel of mAbs from the B cells of an immune individual following a natural nosocomial infection. We determined that the panel comprised antibodies that bound to 2 glycoproteins: (a) the carboxy-terminal glycoprotein (Gc) that serves as the fusion protein and (b) the glycoprotein 38 (GP38). By antibody variable gene analysis, we identified genetic diversity in the B cell response to CCHFV within a single donor for both Gc- and GP38-specific responses. Protection against most bunyavirus-associated diseases is mediated principally by neutralizing antibodies, but here, we found that neutralization activity was not associated with protection. Gc-specific antibodies to diverse antigenic sites neutralized only weakly and did not protect against heterologous virus challenge. GP38-specific antibodies bound to 2 dominant antigenic sites on the glycoprotein. Although GP38-specific antibodies did not neutralize the virus, one mediated protection against heterologous virus challenge in an experimental model of infection in mice primarily by complement-mediated activity. These studies support the development of protective CCHFV countermeasures against GP38.
Authors
Nathaniel S. Chapman, Viktoriya Borisevich, Nurgun Kose, Luke Myers, Stephen Priest, Éric Bergeron, Elena Trigo Esteban, María Paz Sánchez-Seco, José Melero, Thomas W. Geisbert, Robert W. Cross, James E. Crowe Jr.
Abstract
The dynamic assembly and regulation of the IκB kinase (IKK) complex in the NF-κB pathway are central to the pathogenesis and progression of inflammatory bowel disease (IBD). We recently reported that the transcription factor hematopoietically expressed homeobox (HHEX) promotes colitis-associated colorectal cancer, but the potential role of HHEX in intestinal inflammation remains uncharacterized. Here, we found that HHEX is upregulated in inflamed colons in a colitis mouse model and in clinical IBD samples. HHEX overexpression increased inflammatory cytokine expression, and HHEX loss largely abrogated the inflammatory response in vitro and intestinal inflammation in vivo. Mechanistically, IKKα phosphorylates HHEX at S213 to stabilize HHEX in response to TNF-α by inhibiting the interaction of HHEX with the E3 ubiquitin ligase MID2 and subsequent K48-linked ubiquitination and protein degradation. Importantly, HHEX interacted with and stabilized the IKKα/IKKβ complex via its N-terminal domain, thereby activating the NF-κB pathway and establishing a positive feedback loop that exacerbates intestinal inflammation. Our study reveals a transcription-independent function of HHEX in promoting IKK complex assembly and colitis, identifying HHEX as an IBD susceptibility gene and a potential target for IBD treatment.
Authors
Zhebin Hua, Weimin Xu, Wenjun Ding, Zhuoyue Fu, Yaosheng Wang, Yiqing Yang, Fangyuan Liu, Zhujiang Dai, Wenbo Tang, Weijun Ou, Wensong Ge, YingWei Chen, Zhongchuan Wang, Chen-Ying Liu, Peng Du
Abstract
This study investigated how chronic pelvic pain (CPP) develops using rhesus macaques with naturally occurring endometriosis and a multiple lesion induction mouse model (MIM), as repeated retrograde menstruation is considered an underlying mechanism of endometriosis pathogenesis. MIM increased lesion numbers and elevated hypersensitivity. Elevated persistent glial cell activation was observed across multiple brain regions or spinal cords in MIM and rhesus macaques. Elevated TRPV1, SP, and CGRP expressions in the dorsal root ganglia (DRG) were persistent in MIM. MIM induced the severe disappearance of TIM4hiMHCIIlo residential macrophages and an influx of increased pro-inflammatory TIM4loMHCIIhi macrophages in the peritoneal cavity. Cytokine levels were persistently elevated in MIM. Furthermore, dienogest (a synthetic progestin) and fingolimod (a selective immunosuppressor) reduced hyperalgesia and neuroinflammation. Our results indicate that recurrent retrograde menstruation can be a peripheral stimulus that induces nociceptive pain and creates a composite chronic inflammatory stimulus, leading to neuroinflammation and sensitization of the central nervous system. The circuits of neuroplasticity and stimulation of peripheral organs via a feedback loop of neuroinflammation may mediate widespread endometriosis-associated CPP. These findings in mice were further supported by results from the spontaneously developed advanced endometriosis in rhesus macaques via recurrent retrograde menstruation.
Authors
Madeleine E. Harvey, Mingxin Shi, Yeongseok Oh, Taylor M. Page, Debra A. Mitchell, Addie Luo, Ov D. Slayden, James A. MacLean, Anjali Sharma, Kanako Hayashi
Abstract
Gemcitabine-based chemotherapy is the standard treatment regimen for advanced intrahepatic cholangiocarcinoma (iCCA), but the frequent presence of chemoresistance limits its efficacy. Here, we identified isocitrate dehydrogenase 1 (IDH1) as the crucial target that confers chemoresistance of iCCA to gemcitabine using a druggable CRISPR/Cas9 library. The positive association between IDH1 expression and chemoresistance was revealed in a gemcitabine-treated iCCA cohort and with cell-based drug sensitivity assays. Utilizing patient-derived organoids, cell line–derived xenografts, and patient-derived xenografts, we demonstrated that IDH1 knockdown or IDH1 pharmacological inhibition facilitated gemcitabine efficacy in these preclinical iCCA models carrying wild-type IDH1 (wtIDH1). Mechanistically, wtIDH1 oxidizes isocitrate to generate α-ketoglutarate and NNADPH, thereby creating a mechanism to manage the oxidative stress induced by gemcitabine, maintaining cellular redox homeostasis, and, ultimately, leading to chemoresistance to gemcitabine. Significantly, ivosidenib, the FDA-approved allosteric IDH1 inhibitor, demonstrated synergistic antitumor efficacy with gemcitabine in wtIDH1 preclinical iCCA models through boosting intracellular oxidative stress under physiological conditions. The low level of Mg2+, an ion that competitively hinders binding of ivosidenib on wtIDH1, in the iCCA tumor microenvironment contributed to the expanded therapeutic window for use of ivosidenib in patients with iCCA. Our work revealed the potency of combining targeting IDH1 and chemotherapy against wtIDH1 iCCA and other tumors.
Authors
Xiuxian Li, Zhixiao Song, Shusheng Lin, Man Luo, Shaoru Liu, Yang Liu, Fapeng Zhang, Leibo Xu, Chao Liu, Honghua Zhang
No posts were found with this tag.
Copyright © 2026 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)