Secondary lymphedema occurs in up to 20% of patients after lymphadenectomy performed for the surgical management of tumors involving the breast, prostate, uterus, and skin. Patients develop progressive edema of the affected extremity due to retention of protein-rich lymphatic fluid. Despite compression therapy, patients progress to chronic lymphedema in which noncompressible fibrosis and adipose tissue are deposited within the extremity. The presence of fibrosis led to our hypothesis that rosiglitazone, a PPARγ agonist that inhibits fibrosis, would reduce fibrosis in a mouse model of secondary lymphedema after hind limb lymphadenectomy. In vivo, rosiglitazone reduced fibrosis in the hind limb after lymphadenectomy. Our findings verified that rosiglitazone reestablished the adipogenic features of TGF-β1–treated mesenchymal cells in vitro. Despite this, rosiglitazone led to a reduction in adipose tissue deposition. Single-cell RNA-Seq data obtained from human tissues and flow cytometric and histological evaluation of mouse tissues demonstrated increased presence of PDGFRα+ cells in lymphedema; human tissue analysis verified these cells have the capacity for adipogenic and fibrogenic differentiation. Upon treatment with rosiglitazone, we noted a reduction in the overall quantity of PDGFRα+ cells and LipidTOX+ cells. Our findings provide a framework for treating secondary lymphedema as a condition of fibrosis and adipose tissue deposition, both of which, paradoxically, can be prevented with a pro-adipogenic agent.
Ziyu Chen, Soheila Ali Akbari Ghavimi, Mengfan Wu, John McNamara, Olga Barreiro, David Maridas, Radomir Kratchmarov, Ashley Siegel, Sarah Djeddi, Maria Gutierrez-Arcelus, Patrick J. Brennan, Timothy P. Padera, Ulrich von Andrian, Babak Mehrara, Arin K. Greene, C. Ronald Kahn, Dennis P. Orgill, Indranil Sinha, Vicki Rosen, Shailesh Agarwal
Obscurins are giant cytoskeletal proteins with structural and regulatory roles. Obscurin-B (~870 kDa), the largest known isoform, contains two enzymatically active Ser/Thr kinase (kin) domains, kin1 and kin2, which belong to the myosin light chain kinase (MLCK) family. Kin1 binds to and phosphorylates N-cadherin, a major component of the intercalated disc (ICD), the unique sarcolemmal microdomain that mediates the mechanochemical coupling of adjacent cardiomyocytes. Obscurin-B containing kin1 and N-cadherin co-localize at cell junctions in embryonic rat ventricular myocytes (ERVM), and their co-distribution is regulated by Ca2+. Phosphoproteomics analysis revealed that obscurin-kin1 phosphorylates N-cadherin at Ser-788 located within the juxtamembrane region of its cytoplasmic domain with an apparent Kcat of ~5.05 min-1. Overexpression of obscurin-kin1 or phosphomimic-Ser-788-Glu N-cadherin in ERVM markedly increases cell adhesion and chemical coupling. Importantly, phosphomimic-Ser-788-Glu N-cadherin exhibits significantly reduced binding to p120-catenin, while overexpression of phosphoablated-Ser-788-Ala N-cadherin increases RhoA activity. Consistent with an essential role of the obscurin-kin1/N-cadherin axis in cardiomyocyte coupling, it is deregulated in end-stage human heart failure. Given the nearly ubiquitous expression of obscurin and N-cadherin, our findings may have broad applicability in deciphering the obscurin-kin1/N-cadherin axis that likely mediates cell coupling in diverse tissues and organs.
Li Wang, Panagiotis Tsakiroglou, Rex R. Gonzales, Suhan Cho, Amy Li, Cristobal dos Remedios, Nathan T. Wright, Aikaterini Kontrogianni-Konstantopoulos
Patients with cholangiocarcinoma have poor clinical outcomes due to late diagnoses, poor prognoses, and limited treatment strategies. To identify drug combinations for this disease, we have conducted a genome-wide CRISPR screen anchored on the bromodomain and extraterminal domain (BET) PROTAC degrader ARV825, from which we identified anti-cancer synergy when combined with genetic ablation of members of the mTOR pathway. This combination effect was validated using multiple pharmacological BET and mTOR inhibitors, accompanied by increased levels of apoptosis and cell cycle arrest. In a xenograft model, combined BET degradation and mTOR inhibition induced tumor regression. Mechanistically, the two inhibitor classes converged on H3K27ac-marked epigenetic suppression of the serine glycine one carbon (SGOC) metabolism pathway, including the key regulators PHGDH and PSAT1. Knockdown of PSAT1 was sufficient to replicate synergy with single agent inhibition of either BET or mTOR. Our results tie together epigenetic regulation, metabolism, and apoptosis induction as key therapeutic targets for further exploration in this underserved disease.
Yan Zhu, Dengyong Zhang, Pooja Shukla, Young-Ho Jung, Prit Benny Malgulwar, Sharmeen Chagani, Medina Colic, Sarah Benjamin, John A. Copland III, Lin Tan, Philip L. Lorenzi, Milind Javle, Jason T. Huse, Jason Roszik, Traver Hart, Lawrence N. Kwong
The use of patient-derived organoids (PDOs) to characterize therapeutic sensitivity and resistance is a promising precision medicine approach, and its potential to inform clinical decisions is now being tested in several large multi-institutional clinical trials. PDOs are cultivated in extracellular matrix from basement membrane extracts (BMEs) that are most commonly acquired commercially. Each clinical site utilizes distinct BME lots and may be restricted due to the availability of commercial BME sources. However, the impact of different sources of BMEs on organoid drug response is unknown. Here, we tested the impact of BME source on proliferation, drug response, and gene expression in mouse and human pancreatic ductal adenocarcinoma (PDA) organoids. Both human and mouse organoids displayed increased proliferation in Matrigel (Corning) compared to Cultrex (RnD) and UltiMatrix (RnD). However, we observed no substantial impact on drug response when organoids were cultured in Matrigel, Cultrex, or UltiMatrix. We also did not observe major shifts in gene expression across the different BME sources, and PDOs maintained their Classical or Basal-like designation. Overall, we find that BME source (Matrigel, Cultrex, UltiMatrix) does not shift PDO dose-response curves and drug testing results, indicating that PDO pharmacotyping is a robust approach for precision medicine.
Jan C. Lumibao, Shira R. Okhovat, Kristina L. Peck, Xiaoxue Lin, Kathryn Lande, Shira Yomtoubian, Isabella Ng, Herve Tiriac, Andrew M. Lowy, Jingjing Zou, Dannielle D. Engle
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
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