Drug-induced liver injury (DILI), especially acetaminophen overdose, is the leading cause of acute liver failure. Pregnane X receptor (PXR) is a nuclear receptor and the master regulator of drug metabolism. Aberrant activation of PXR plays a pathogenic role in the acetaminophen hepatotoxicity. Here, we aimed to examine the PXR S-nitrosylation (SNO) in response to acetaminophen. We found that PXR was S-nitrosylated in hepatocytes and the mouse livers after exposure to acetaminophen or S-nitrosoglutathione (GSNO). Mass-spectrometry and site-directed mutagenesis identified the cysteine 307 as the primary residue for SNO-modification. In hepatocytes, SNO suppressed both agonist (rifampicin and SR12813)-induced and constitutively active PXR (VP-PXR) activations. Furthermore, in acetaminophen overdosed mouse livers, PXR protein was decreased at the centrilobular regions overlapping with increased SNO. In PXR-deficient (PXR-/-) mice, replenishing the livers with the SNO-deficient PXR significantly aggravated hepatic necrosis, increased HMGB1 release, and exacerbated liver injury and inflammation. Particularly, we demonstrated that S-nitrosoglutathione reductase (GSNOR) inhibitor N6022 promoted hepatoprotection by increasing the levels of PXR S-nitrosylation. In conclusion, PXR is post-translationally modified by S-nitrosylation in hepatocytes in response to acetaminophen. This modification mitigated the acetaminophen-induced PXR hyperactivity. It may serve as a target for therapeutical intervention.
Qi Cui, Tingting Jiang, Xinya Xie, Haodong Wang, Lei Qian, Yanyan Cheng, Qiang Li, Tingxu Lu, Qinyu Yao, Jia Liu, Baochang Lai, Chang Chen, Lei Xiao, Nanping Wang
Benign prostatic hyperplasia (BPH) is the nodular proliferation of the prostate transition zone in older men, leading to urinary storage and voiding problems that can be recalcitrant to therapy. Decades ago, John McNeal proposed that BPH originates with the “reawakening” of embryonic inductive activity by adult prostate stroma, which spurs new ductal proliferation and branching morphogenesis. Here, by laser microdissection and transcriptional profiling of the BPH stroma adjacent to hyperplastic branching ducts, we identified secreted factors likely mediating stromal induction of prostate glandular epithelium and coinciding processes. The top stromal factors were Insulin Like Growth Factor 1 (IGF1) and C-X-C Motif Chemokine Ligand 13 (CXCL13), which we confirmed by RNA in situ hybridization to be co-expressed in BPH fibroblasts, along with their cognate receptors (IGF1R and CXCR5) on adjacent epithelium. In contrast, IGF1 but not CXCL13 was expressed in human embryonic prostate stroma. Finally, we demonstrated that IGF1 is necessary for the generation of BPH-1 cell spheroids and patient-derived BPH cell organoids in three-dimensional culture. Our findings partially support historic speculations on the etiology of BPH, and provide what we believe to be new molecular targets for rational therapies directed against the underlying processes driving BPH.
Anna S. Pollack, Christian A. Kunder, Noah Brazer, Zhewei Shen, Sushama Varma, Robert B. West, Gerald R. Cunha, Laurence S. Baskin, James D. Brooks, Jonathan R. Pollack
Syndromic ciliopathies and retinal degenerations are large heterogeneous groups of genetic diseases. Pathogenic variants in the CFAP418 gene may cause both disorders, and its protein sequence is evolutionarily conserved. However, the disease mechanism underlying CFAP418 mutations has not been explored. Here, we apply quantitative lipidomic, proteomic, and phosphoproteomic profiling and affinity purification coupled with mass spectrometry to address the molecular function of CFAP418 in retinas. We show that CFAP418 protein binds to lipid metabolism precursor phosphatidic acid (PA) and mitochondrion-specific lipid cardiolipin but does not form a tight and static complex with proteins. Loss of Cfap418 in mice disturbs membrane lipid homeostasis and membrane-protein association, which subsequently causes mitochondrial defects and membrane remodeling abnormalities across multiple vesicular trafficking pathways in photoreceptors, especially the endosomal sorting complexes required for transport (ESCRT) pathway. Ablation of Cfap418 also increases the activity of PA-binding protein kinase Cα in the retina. Overall, our results indicate that membrane lipid imbalance is a pathological mechanism underlying syndromic ciliopathies and retinal degenerations, which is associated with other known causative genes of these diseases.
Anna M. Clark, Dongmei Yu, Grace Neiswanger, Daniel Zhu, Junhuang Zou, J. Alan Maschek, Thomas Burgoyne, Jun Yang
Despite strong indications that melanoma interaction with lymphatic vessels actively promotes melanoma progression, the molecular mechanisms are not yet completely understood. To characterize molecular factors of this crosstalk we established human primary lymphatic endothelial cell (LEC) co-cultures with human melanoma cell lines. Here, we show that co-culture with melanoma cells induced transcriptomic changes in LECs and led to multiple alterations in their function. WNT5B, a paracrine signaling molecule upregulated in melanoma cells upon LEC interaction, was found contributing to the functional changes in LECs. Moreover, WNT5B transcription was regulated by Notch3 in melanoma cells following the co-culture with LECs, and Notch3 and WNT5B were coexpressed in melanoma patient primary tumor and metastasis samples. Moreover, melanoma cells derived from LEC co-culture escaped efficiently from the primary site to the proximal tumor draining lymph nodes, which was impaired upon WNT5B depletion. This supported the role of WNT5B in promoting the metastatic potential of melanoma cells through its effects on LECs. Finally, DLL4, a Notch ligand expressed in LECs, was identified as an upstream inducer of the Notch3-WNT5B axis in melanoma. This study elucidated WNT5B as a key molecular factor mediating bi-directional crosstalk between melanoma cells and lymphatic endothelium and promoting melanoma metastasis.
Sanni Alve, Silvia Gramolelli, Joonas Jukonen, Susanna Juteau, Anne Pink, Atte A. Manninen, Satu Hänninen, Elisa Monto, Madeleine H. Lackman, Olli Carpén, Pipsa Saharinen, Sinem Karaman, Kari Vaahtomeri, Päivi M. Ojala
The histone demethylase JMJD2A/KDM4A facilitates prostate cancer development, yet how JMJD2A function is regulated has remained elusive. Here, we demonstrate that SET7/9-mediated methylation on 6 lysine residues modulated JMJD2A. Joint mutation of these lysine residues suppressed JMJD2A’s ability to stimulate the MMP1 matrix metallopeptidase promoter upon recruitment by the ETV1 transcription factor. Mutation of just 3 methylation sites (K505, K506, and K507) to arginine residues (3xR mutation) was sufficient to maximally reduce JMJD2A transcriptional activity and also decreased its binding to ETV1. Introduction of the 3xR mutation into DU145 prostate cancer cells reduced in vitro growth and invasion and also severely compromised tumorigenesis. Consistently, the 3xR genotype caused transcriptome changes related to cell proliferation and invasion pathways, including downregulation of MMP1 and the NPM3 nucleophosmin/nucleoplasmin gene. NPM3 downregulation phenocopied and its overexpression rescued, to a large degree, the 3xR mutation in DU145 cells, suggesting that NPM3 was a seminal downstream effector of methylated JMJD2A. Moreover, we found that NPM3 was overexpressed in prostate cancer and might be indicative of disease aggressiveness. SET7/9-mediated lysine methylation of JMJD2A may aggravate prostate tumorigenesis in a manner dependent on NPM3, implying that the SET7/9→JMJD2A→NPM3 axis could be targeted for therapy.
Ruicai Gu, Tae-Dong Kim, Hoogeun Song, Yuan Sui, Sook Shin, Sangphil Oh, Ralf Janknecht
MTORC1 integrates signaling from the immune microenvironment to regulate T cell activation, differentiation, and function. TSC2 in the tuberous sclerosis complex tightly regulates mTORC1 activation. CD8+ T cells lacking TSC2 have constitutively enhanced mTORC1 activity and generate robust effector T cells; however sustained mTORC1 activation prevents generation of long-lived memory CD8+ T cells. Here we show manipulating TSC2 at Ser1365 potently regulates activated but not basal mTORC1 signaling in CD8+ T cells. Unlike non-stimulated TSC2 knockout cells, CD8+ T cells expressing a phospho-silencing mutant TSC2-S1365A (SA) retain normal basal mTORC1 activity. PKC and T-cell Receptor (TCR) stimulation induces TSC2 S1365 phosphorylation and preventing this with the SA mutation markedly increases mTORC1 activation and T-cell effector function. Consequently, SA CD8+ T cells display greater effector responses while retaining their capacity to become long-lived memory T cells. SA CD8+ T cells also display enhanced effector function under hypoxic and acidic conditions. In murine and human solid-tumor models, CD8+ SA T cells used as adoptive cell therapy display greater anti-tumor immunity than WT CD8+ T cells. These findings reveal an upstream mechanism to regulate mTORC1 activity in T cells. The TSC2-SA mutation enhances both T cell effector function and long-term persistence/memory formation, supporting an approach to engineer better CAR-T cells for treating cancer.
Chirag H. Patel, Yi Dong, Navid Koleini, Xiaoxu Wang, Brittany L. Dunkerly-Eyring, Jiayu Wen, Mark J. Ranek, Laura M. Bartle, Daniel B. Henderson, Jason G. Sagert, David A. Kass, Jonathan D. Powell
Factor inhibiting HIF (FIH) is an asparagine hydroxylase that acts on hypoxia inducible factors (HIFs) to control cellular adaptation to hypoxia. FIH is expressed in several tumor types, but its impact in tumor progression remains largely unexplored. We observed that FIH was expressed on human lung cancer tissue. Deletion of FIH in mouse and human lung cancer cells resulted in an increased glycolytic metabolism, consistent with increased HIF activity. FIH-deficient lung cancer cells exhibited decreased proliferation. Analysis of RNA-seq data confirmed changes in the cell cycle and survival, and revealed molecular pathways that were dysregulated in the absence of FIH including the upregulation of angiomotin (Amot), a key component of the Hippo tumor suppressor pathway. We show that FIH-deficient tumors were characterized by higher immune infiltration of NK and T cells compared to FIH competent tumor cells. In vivo studies demonstrated that FIH deletion resulted in reduced tumor growth and metastatic capacity. Moreover, high FIH expression correlated with poor overall survival in non-small cell lung cancer (NSCLC). Together, our data unravel FIH as a therapeutic target for the treatment of lung cancer.
Ana García-del Río, Endika Prieto-Fernández, Leire Egia-Mendikute, Asier Antoñana-Vildosola, Borja Jimenez-Lasheras, So Young Lee, Adrián Barreira-Manrique, Samanta Romina Zanetti, Ander de Blas, Paloma Velasco-Beltrán, Alexandre Bosch, Ana M. Aransay, Asis Palazon
Epithelial Na+ channels (ENaCs) control extracellular fluid volume by facilitating Na+ absorption across transporting epithelia. In vitro studies showed that Cys-palmitoylation of the γ ENaC subunit is a major regulator of channel activity. We tested whether γ subunit palmitoylation sites are necessary for channel function in vivo by generating mice lacking the palmitoylated cysteines (γC33A,C41A) using CRISPR-Cas9 technology. ENaCs in dissected kidney tubules from γC33A,C41A mice had reduced open probability compared to wild type (WT) littermates maintained on either standard or Na+-deficient diets. Male mutant mice also had higher aldosterone levels than WT littermates following Na+ restriction. However, γC33A,C41A mice did not have reduced amiloride-sensitive Na+ currents in the distal colon or benzamil-induced natriuresis compared to WT mice. We identified a second, larger conductance cation channel in the distal nephron with biophysical properties distinct from ENaC. The activity of this channel was higher in Na+-restricted γC33A,C41A versus WT mice and was blocked by benzamil, providing a possible compensatory mechanism for reduced prototypic ENaC function. We conclude that γ subunit palmitoylation sites are required for prototypic ENaC activity in vivo, but are not necessary for amiloride/benzamil-sensitive Na+ transport in the distal nephron or colon.
Andrew J. Nickerson, Stephanie M. Mutchler, Shaohu Sheng, Natalie A. Cox, Evan C. Ray, Ossama B. Kashlan, Marcelo D. Carattino, Allison L. Marciszyn, Aaliyah Winfrey, Sebastien Gingras, Annet Kirabo, Rebecca P. Hughey, Thomas R. Kleyman
Superficial erythematous cutaneous vascular malformations are assumed to be blood vascular in origin, but cutaneous lymphatic malformations can contain blood and appear red. Management may be different and so an accurate diagnosis is important. Cutaneous malformations were investigated through 2D-histology and 3D-whole-mount-histology. Two lesions were clinically considered as port-wine birthmark, and another three lesions as erythematous telangiectasias. The aims were: i) to prove that cutaneous erythematous malformations including telangiectasia can represent a lymphatic phenotype, ii) to determine if lesions represent expanded but otherwise normal or malformed lymphatics, and iii) to determine if the presence of erythrocytes explained the red colour. Microscopy revealed all lesions as lymphatic structures. Port-wine birthmarks proved to be cystic lesions, with non-uniform lymphatic marker expression, and a disconnected lymphatic network suggesting a lymphatic malformation. Erythematous telangiectasias represented expanded but non-malformed lymphatics. Blood within lymphatics appeared to explain the colour. Blood-lymphatic-shunts could be detected in the erythematous telangiectasia. In conclusion, erythematous cutaneous capillary lesions may be lymphatic in origin but clinically indistinguishable from blood vascular malformations. Biopsy is advised for correct phenotyping and management. Erythrocytes are the likely explanation for colour accessing lymphatics through lympho-venous-shunts.
René Hägerling, Malou Van Zanten, Rose Yinghan Behncke, Sascha Ulferts, Nils R. Hansmeier, Bruno Märkl, Christian Witzel, Bernard Ho, Vaughan Keeley, Katie Riches, Sahar Mansour, Kristiana Gordon, Pia Ostergaard, Peter S. Mortimer
The identity and origin of the stem/progenitor cells for adult joint cartilage repair remain unknown, impeding therapeutic development. Simulating the common therapeutic modality for cartilage repair in humans, i.e., full-thickness microfracture joint surgery, we combined the mouse full-thickness injury model with lineage tracing and identified a distinct skeletal progenitor cell type enabling long-term (beyond 7 days after injury) articular cartilage repair in vivo. Deriving from a population with active Prg4 expression in adulthood while lacking aggrecan expression, these progenitors proliferate, differentiate to express aggrecan and type II collagen, and predominate in long-term articular cartilage wounds, where they represent the principal repair progenitors in situ under native repair conditions without cellular transplantation. They originate outside the adult bone marrow or superficial zone articular cartilage. These findings have implications for skeletal biology and regenerative medicine for joint injury repair.
Mei Massengale, Justin L. Massengale, Catherine R. Benson, Ninib Barywano, Toshihiko Oki, Matthew L. Steinhauser, Alissa Wang, Deepak Balani, Luke S. Oh, Mark A. Randolph, Thomas J. Gill III, Henry M. Kronenberg, David T. Scadden
No posts were found with this tag.