Browsing by Author "Yi, Xin"
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Item Author Correction: Salt-dependent Blood Pressure in Human Aldosterone Synthase-Transgenic Mice(Springer Nature, 2018-10-25) Gu, Huiying; Ma, Zhizhong; Wang, Jian; Zhu, Timothy; Du, Nicole; Shatara, Adam; Yi, Xin; Kowala, Mark C.; Du, Yansheng; Neurology, School of MedicineA correction has been published and is appended to both the HTML and PDF versions of this paper. The error has not been fixed in the paper.Item Gabapentin Disrupts Binding of Perlecan to the α2δ1 Voltage Sensitive Calcium Channel Subunit and Impairs Skeletal Mechanosensation(MDPI, 2022-12-12) Reyes Fernandez, Perla C.; Wright, Christian S.; Masterson, Adrianna N.; Yi, Xin; Tellman, Tristen V.; Bonteanu, Andrei; Rust, Katie; Noonan, Megan L.; White, Kenneth E.; Lewis, Karl J.; Sankar, Uma; Hum, Julia M.; Bix, Gregory; Wu, Danielle; Robling, Alexander G.; Sardar, Rajesh; Farach-Carson, Mary C.; Thompson, William R.; Physical Therapy, School of Health and Human SciencesOur understanding of how osteocytes, the principal mechanosensors within bone, sense and perceive force remains unclear. Previous work identified "tethering elements" (TEs) spanning the pericellular space of osteocytes and transmitting mechanical information into biochemical signals. While we identified the heparan sulfate proteoglycan perlecan (PLN) as a component of these TEs, PLN must attach to the cell surface to induce biochemical responses. As voltage-sensitive calcium channels (VSCCs) are critical for bone mechanotransduction, we hypothesized that PLN binds the extracellular α2δ1 subunit of VSCCs to couple the bone matrix to the osteocyte membrane. Here, we showed co-localization of PLN and α2δ1 along osteocyte dendritic processes. Additionally, we quantified the molecular interactions between α2δ1 and PLN domains and demonstrated for the first time that α2δ1 strongly associates with PLN via its domain III. Furthermore, α2δ1 is the binding site for the commonly used pain drug, gabapentin (GBP), which is associated with adverse skeletal effects when used chronically. We found that GBP disrupts PLN::α2δ1 binding in vitro, and GBP treatment in vivo results in impaired bone mechanosensation. Our work identified a novel mechanosensory complex within osteocytes composed of PLN and α2δ1, necessary for bone force transmission and sensitive to the drug GBP.Item Generation of two multipotent mesenchymal progenitor cell lines capable of osteogenic, mature osteocyte, adipogenic, and chondrogenic differentiation(Springer Nature, 2021-11-19) Prideaux, Matthew; Wright, Christian S.; Noonan, Megan L.; Yi, Xin; Clinkenbeard, Erica L.; Mevel, Elsa; Wheeler, Jonathan A.; Byers, Sharon; Wijenayaka, Asiri R.; Gronthos, Stan; Sankar, Uma; White, Kenneth E.; Atkins, Gerald J.; Thompson, William R.; Physical Therapy, School of Health and Human SciencesMesenchymal progenitors differentiate into several tissues including bone, cartilage, and adipose. Targeting these cells in vivo is challenging, making mesenchymal progenitor cell lines valuable tools to study tissue development. Mesenchymal stem cells (MSCs) can be isolated from humans and animals; however, obtaining homogenous, responsive cells in a reproducible fashion is challenging. As such, we developed two mesenchymal progenitor cell (MPC) lines, MPC1 and MPC2, generated from bone marrow of male C57BL/6 mice. These cells were immortalized using the temperature sensitive large T-antigen, allowing for thermal control of proliferation and differentiation. Both MPC1 and MPC2 cells are capable of osteogenic, adipogenic, and chondrogenic differentiation. Under osteogenic conditions, both lines formed mineralized nodules, and stained for alizarin red and alkaline phosphatase, while expressing osteogenic genes including Sost, Fgf23, and Dmp1. Sost and Dmp1 mRNA levels were drastically reduced with addition of parathyroid hormone, thus recapitulating in vivo responses. MPC cells secreted intact (iFGF23) and C-terminal (cFGF23) forms of the endocrine hormone FGF23, which was upregulated by 1,25 dihydroxy vitamin D (1,25D). Both lines also rapidly entered the adipogenic lineage, expressing adipose markers after 4 days in adipogenic media. MPC cells were also capable of chondrogenic differentiation, displaying increased expression of cartilaginous genes including aggrecan, Sox9, and Comp. With the ability to differentiate into multiple mesenchymal lineages and mimic in vivo responses of key regulatory genes/proteins, MPC cells are a valuable model to study factors that regulate mesenchymal lineage allocation as well as the mechanisms that dictate transcription, protein modification, and secretion of these factors.Item High glucose-induced Matrilin-2 expression in mouse mesangial cells was mediated by transforming growth factor beta 1 (TGF-β1)(Elsevier, 2016-05) Zhang, Shukun; Zhang, Menglan; Huang, Hong; Zhou, Shiying; Du, Yanshneg; Yi, Xin; Luo, Junming; Department of Health Sciences, School of Health and Rehabilitation SciencesThis study aimed at evaluating the effect of high glucose on the expression of extracellular matrix (ECM) protein Matrilin-2 and the mechanism underlying this effect by using a mouse mesangial cell line. Mouse mesangial cells (MMCs) were cultured in media containing normal (5 mM d-glucose) or high concentrations of glucose (30 mM d-glucose). The expression of Matrilin-2 was assessed by either RT-PCR or western blot. Additionally, transforming growth factor beta 1 (TGF-β1) inhibitors and TGF-β1 were used to determine whether glucose-regulated Matrilin-2 expression was mediated by the TGF-β1/Smad3 signaling pathway. Our data demonstrated that Matrilin-2 expression was markedly induced by high glucose and TGF-β1. High glucose-induced Matrilin-2 expression was inhibited by TGF-β1/Smad3 inhibitors, indicating that Matrilin-2 was markedly induced by high glucose and this induction was mediated by the TGF-β1/Smad3 pathway. Taken together, our results showed that high-glucose-induced Matrilin-2 expression that was mediated by the TGF-β1/Smad3 signaling pathway might play a role in Diabetic nephropathy (DN) pathogenesis and our finding provided a potential diagnostic and/or therapeutic target for DN.Item Loss of the auxiliary α2δ1 voltage-sensitive calcium channel subunit impairs bone formation and anabolic responses to mechanical loading(Oxford University Press, 2024-01-10) Kelly, Madison M.; Sharma, Karan; Wright, Christian S.; Yi, Xin; Reyes Fernandez, Perla C.; Gegg, Aaron T.; Gorrell, Taylor A.; Noonan, Megan L.; Baghdady, Ahmed; Sieger, Jacob A.; Dolphin, Annette C.; Warden, Stuart J.; Deosthale, Padmini; Plotkin, Lilian I.; Sankar, Uma; Hum, Julia M.; Robling, Alexander G.; Farach-Carson, Mary C.; Thompson, William R.; Physical Therapy, School of Health and Human SciencesVoltage-sensitive calcium channels (VSCCs) influence bone structure and function, including anabolic responses to mechanical loading. While the pore-forming (α1) subunit of VSCCs allows Ca2+ influx, auxiliary subunits regulate the biophysical properties of the pore. The α2δ1 subunit influences gating kinetics of the α1 pore and enables mechanically induced signaling in osteocytes; however, the skeletal function of α2δ1 in vivo remains unknown. In this work, we examined the skeletal consequences of deleting Cacna2d1, the gene encoding α2δ1. Dual-energy X-ray absorptiometry and microcomputed tomography imaging demonstrated that deletion of α2δ1 diminished bone mineral content and density in both male and female C57BL/6 mice. Structural differences manifested in both trabecular and cortical bone for males, while the absence of α2δ1 affected only cortical bone in female mice. Deletion of α2δ1 impaired skeletal mechanical properties in both sexes, as measured by three-point bending to failure. While no changes in osteoblast number or activity were found for either sex, male mice displayed a significant increase in osteoclast number, accompanied by increased eroded bone surface and upregulation of genes that regulate osteoclast differentiation. Deletion of α2δ1 also rendered the skeleton insensitive to exogenous mechanical loading in males. While previous work demonstrates that VSCCs are essential for anabolic responses to mechanical loading, the mechanism by which these channels sense and respond to force remained unclear. Our data demonstrate that the α2δ1 auxiliary VSCC subunit functions to maintain baseline bone mass and strength through regulation of osteoclast activity and also provides skeletal mechanotransduction in male mice. These data reveal a molecular player in our understanding of the mechanisms by which VSCCs influence skeletal adaptation.Item Mechanical suppression of breast cancer cell invasion and paracrine signaling to osteoclasts requires nucleo-cytoskeletal connectivity(Nature, 2020-11-17) Yi, Xin; Wright, Laura E.; Pagnotti, Gabriel M.; Uzer, Gunes; Powell, Katherine M.; Wallace, Joseph M.; Sankar, Uma; Rubin, Clinton T.; Mohammad, Khalid; Guise, Theresa A.; Thompson, William R.; Physical Therapy, School of Health and Human SciencesExercise benefits the musculoskeletal system and reduces the effects of cancer. The effects of exercise are multifactorial, where metabolic changes and tissue adaptation influence outcomes. Mechanical signals, a principal component of exercise, are anabolic to the musculoskeletal system and restrict cancer progression. We examined the mechanisms through which cancer cells sense and respond to low-magnitude mechanical signals introduced in the form of vibration. Low-magnitude, high-frequency vibration was applied to human breast cancer cells in the form of low-intensity vibration (LIV). LIV decreased matrix invasion and impaired secretion of osteolytic factors PTHLH, IL-11, and RANKL. Furthermore, paracrine signals from mechanically stimulated cancer cells, reduced osteoclast differentiation and resorptive capacity. Disconnecting the nucleus by knockdown of SUN1 and SUN2 impaired LIV-mediated suppression of invasion and osteolytic factor secretion. LIV increased cell stiffness; an effect dependent on the LINC complex. These data show that mechanical vibration reduces the metastatic potential of human breast cancer cells, where the nucleus serves as a mechanosensory apparatus to alter cell structure and intercellular signaling.Item The mTORC2 Component Rictor Is Required for Load-Induced Bone Formation in Late-Stage Skeletal Cells(Wiley, 2020-04-17) Lewis, Karl J.; Yi, Xin; Wright, Christian S.; Pemberton, Emily Z.; Bullock, Whitney A.; Thompson, William R.; Robling, Alexander G.; Anatomy and Cell Biology, School of MedicineBone relies on mechanical cues to build and maintain tissue composition and architecture. Our understanding of bone cell mechanotransduction continues to evolve, with a few key signaling pathways emerging as vital. Wnt/β‐catenin, for example, is essential for proper anabolic response to mechanical stimulation. One key complex that regulates β‐catenin activity is the mammalian target of rapamycin complex 2 (mTORc2). mTORc2 is critical for actin cytoskeletal reorganization, an indispensable component in mechanotransduction in certain cell types. In this study, we probed the impact of the mTORc2 signaling pathway in osteocyte mechanotransduction by conditionally deleting the mTORc2 subunit Rictor in Dmp1‐expressing cells of C57BL/6 mice. Conditional deletion of the Rictor was achieved using the Dmp1–Cre driver to recombine Rictor floxed alleles. Rictor mutants exhibited a decrease in skeletal properties, as measured by DXA, μCT, and mechanical testing, compared with Cre‐negative floxed littermate controls. in vivo axial tibia loading conducted in adult mice revealed a deficiency in the osteogenic response to loading among Rictor mutants. Histological measurements of osteocyte morphology indicated fewer, shorter cell processes in Rictor mutants, which might explain the compromised response to mechanical stimulation. In summary, inhibition of the mTORc2 pathway in late osteoblasts/osteocytes leads to decreased bone mass and mechanically induced bone formation.Item Response to correspondence on “Reproducibility of CRISPR-Cas9 methods for generation of conditional mouse alleles: a multi-center evaluation”(BMC, 2021-04-07) Gurumurthy, Channabasavaiah B.; O’Brien, Aidan R.; Quadros, Rolen M.; Adams, John, Jr.; Alcaide, Pilar; Ayabe, Shinya; Ballard, Johnathan; Batra, Surinder K.; Beauchamp, Marie-Claude; Becker, Kathleen A.; Bernas, Guillaume; Brough, David; Carrillo-Salinas, Francisco; Chan, Wesley; Chen, Hanying; Dawson, Ruby; DeMambro, Victoria; D’Hont, Jinke; Dibb, Katharine; Eudy, James D.; Gan, Lin; Gao, Jing; Gonzales, Amy; Guntur, Anyonya; Guo, Huiping; Harms, Donald W.; Harrington, Anne; Hentges, Kathryn E.; Humphreys, Neil; Imai, Shiho; Ishii, Hideshi; Iwama, Mizuho; Jonasch, Eric; Karolak, Michelle; Keavney, Bernard; Khin, Nay-Chi; Konno, Masamitsu; Kotani, Yuko; Kunihiro, Yayoi; Lakshmanan, Imayavaramban; Larochelle, Catherine; Lawrence, Catherine B.; Li, Lin; Lindner, Volkhard; Liu, Xian-De; Lopez-Castejon, Gloria; Loudon, Andrew; Lowe, Jenna; Jerome-Majeweska, Loydie; Matsusaka, Taiji; Miura, Hiromi; Miyasaka, Yoshiki; Morpurgo, Benjamin; Moty, Katherine; Nabeshima, Yo-ichi; Nakade, Koji; Nakashiba, Toshiaki; Nakashima, Kenichi; Obata, Yuichi; Ogiwara, Sanae; Ouellet, Mariette; Oxburgh, Leif; Piltz, Sandra; Pinz, Ilka; Ponnusamy, Moorthy P.; Ray, David; Redder, Ronald J.; Rosen, Clifford J.; Ross, Nikki; Ruhe, Mark T.; Ryzhova, Larisa; Salvador, Ane M.; Shameen Alam, Sabrina; Sedlacek, Radislav; Sharma, Karan; Smith, Chad; Staes, Katrien; Starrs, Lora; Sugiyama, Fumihiro; Takahashi, Satoru; Tanaka, Tomohiro; Trafford, Andrew; Uno, Yoshihiro; Vanhoutte, Leen; Vanrockeghem, Frederique; Willis, Brandon J.; Wright, Christian S.; Yamauchi, Yuko; Yi, Xin; Yoshimi, Kazuto; Zhang, Xuesong; Zhang, Yu; Ohtsuka, Masato; Das, Satyabrata; Garry, Daniel J.; Hochepied, Tino; Thomas, Paul; Parker-Thornburg, Jan; Adamson, Antony D.; Yoshiki, Atsushi; Schmouth, Jean-Francois; Golovko, Andrei; Thompson, William R.; Lloyd, K.C. Kent; Wood, Joshua A.; Cowan, Mitra; Mashimo, Tomoji; Mizuno, Seiya; Zhu, Hao; Kasparek, Petr; Liaw, Lucy; Miano, Joseph M.; Burgio, Gaetan; Medicine, School of MedicineItem Rnd3/RhoE Modulates HIF1α/VEGF Signaling by Stabilizing HIF1α and Regulates Responsive Cardiac Angiogenesis(American Heart Association, 2016-03) Yue, Xiaojing; Yang, Tingli; Lin, Xi; Yang, Xiangsheng; Yi, Xin; Jiang, Xuejun; Li, Xiaoyan; Li, Tianfa; Guo, Junli; Dai, Yuan; Shi, Jianjian; Wei, Lei; Youker, Keith A.; Torre-Amione, Guillermo; Yu, Yanhong; Andrade, Kelsey C.; Chang, Jiang; Department of Pediatrics, IU School of MedicineThe insufficiency of compensatory angiogenesis in the heart of patients with hypertension contributes to heart failure transition. The hypoxia-inducible factor 1α-vascular endothelial growth factor (HIF1α-VEGF) signaling cascade controls responsive angiogenesis. One of the challenges in reprograming the insufficient angiogenesis is to achieve a sustainable tissue exposure to the proangiogenic factors, such as HIF1α stabilization. In this study, we identified Rnd3, a small Rho GTPase, as a proangiogenic factor participating in the regulation of the HIF1α-VEGF signaling cascade. Rnd3 physically interacted with and stabilized HIF1α, and consequently promoted VEGFA expression and endothelial cell tube formation. To demonstrate this proangiogenic role of Rnd3 in vivo, we generated Rnd3 knockout mice. Rnd3 haploinsufficient (Rnd3(+/-)) mice were viable, yet developed dilated cardiomyopathy with heart failure after transverse aortic constriction stress. The poststress Rnd3(+/-) hearts showed significantly impaired angiogenesis and decreased HIF1α and VEGFA expression. The angiogenesis defect and heart failure phenotype were partially rescued by cobalt chloride treatment, a HIF1α stabilizer, confirming a critical role of Rnd3 in stress-responsive angiogenesis. Furthermore, we generated Rnd3 transgenic mice and demonstrated that Rnd3 overexpression in heart had a cardioprotective effect through reserved cardiac function and preserved responsive angiogenesis after pressure overload. Finally, we assessed the expression levels of Rnd3 in the human heart and detected significant downregulation of Rnd3 in patients with end-stage heart failure. We concluded that Rnd3 acted as a novel proangiogenic factor involved in cardiac responsive angiogenesis through HIF1α-VEGFA signaling promotion. Rnd3 downregulation observed in patients with heart failure may explain the insufficient compensatory angiogenesis involved in the transition to heart failure.Item Salt-dependent Blood Pressure in Human Aldosterone Synthase-Transgenic Mice(Springer Nature, 2017-03-28) Gu, Huiying; Ma, Zhizhong; Wang, Jian; Zhu, Timothy; Du, Nicole; Shatara, Adam; Yi, Xin; Kowala, Mark C.; Du, Yansheng; Department of Neurology, IU School of MedicineHypertension is one of the most important, preventable causes of premature morbidity and mortality in the developed world. Aldosterone is a major mineralocorticoid hormone that plays a key role in the regulation of blood pressure and is implicated in the pathogenesis of hypertension and heart failure. Aldosterone synthase (AS, cytochrome P450 11B2, cyp11B2) is the sole enzyme responsible for the production of aldosterone in humans. To determine the effects of increased expression of human aldosterone synthase (hAS) on blood pressure (BP), we established transgenic mice carrying the hAS gene (cyp11B2). We showed that hAS overexpression increased levels of aldosterone in hAS+/− mice. On high salt diet (HS), BPs of hAS+/− mice were significantly increased compared with WT mice. Fadrozole (an inhibitor of aldosterone synthase) treatment significantly reduced BPs of hAS+/− mice on HS. This is the first time overexpression of AS in a transgenic mouse line has shown an ability to induce HP. Specifically inhibiting AS activity in these mice is a promising therapy for reducing hypertension. This hAS transgenic mouse model is therefore an ideal animal model for hypertension therapy studies.