Lin, Yang

ABSTRACTDegenerative disk disease of the spine is a major cause of back pain and disability. Optimization of regenerative medical therapies for degenerative disk disease requires a deep mechanistic understanding of the factors controlling the structural integrity of spinal tissues. In this investigation, we sought to identify candidate regulatory genes controlling extracellular matrix synthesis in spinal tissues. To achieve this goal we performed high throughput next generation RNA sequencing on 39 annulus fibrosus and 21 nucleus pulposus human tissue samples. Specimens were collected from patients undergoing surgical discectomy for the treatment of degenerative disk disease. Our studies identified associations between extracellular matrix genes, growth factors, and other important regulatory molecules. The fibrous matrix characteristic of annulus fibrosus was associated with expression of the growth factors platelet derived growth factor beta (PDGFB), vascular endothelial growth factor C (VEGFC), and fibroblast growth factor 9 (FGF9). Additionally we observed high expression of multiple signaling proteins involved in the NOTCH and WNT signaling cascades. Nucleus pulposus extracellular matrix related genes were associated with the expression of numerous diffusible growth factors largely associated with the transforming growth signaling cascade, including transforming factor alpha (TGFA), inhibin alpha (INHA), inhibin beta A (INHBA), bone morphogenetic proteins (BMP2, BMP6), and others. Clinical significance: this investigation provides important data on extracellular matrix gene regulatory networks in disk tissues. This information can be used to optimize pharmacologic, stem cell, and tissue engineering strategies for regeneration of the intervertebral disk and the treatment of back pain. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1356–1369, 2018.

AbstractAdipose-derived mesenchymal stem cells (AMSCs) offer potential as a therapeutic option for clinical applications in musculoskeletal regenerative medicine because of their immunomodulatory functions and capacity for trilineage differentiation. In preparation for a phase I clinical trial using AMSCs to treat patients with osteoarthritis, we carried out preclinical studies to assess the safety of human AMSCs within the intra-articular joint space. Culture-expanded human AMSCs grown in human platelet-lysate were delivered via intra-articular injections into normal healthy rabbit knees and knees at risk for the development of osteoarthritis after bilateral medial anterior hemimeniscectomy. Treatment outcomes and safety were evaluated by assessing the general health, function, and behavior of the animals. Joint tissues were analyzed by x-ray, magnetic resonance imaging, and histopathology. Intra-articular AMSC therapy was well tolerated in this study. We did not observe adverse systemic reactions, nor did we find evidence of damage to intra-articular joint tissues. Thus, the data generated in this study show a favorable safety profile for AMSCs within the joint space in support of a phase I clinical trial evaluating the clinical utility of AMSCs to treat osteoarthritis.

Abstract Lung cancer accounts for about 27% of the cancer related deaths in the USA annually. Pathologically, it is a very complex disease broadly classified into small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). NSCLCs are further classified into squamous cell carcinoma, large cell carcinoma and adenocarcinoma. Achaete-scute homolog 1 (ASCL1), an important transcription factor essential in the development of neuroendocrine cells (NE) in lungs is shown to be specifically expressed in lung NE cancers and 10-20% of adenocarcinomas (AD) with NE differentiation (NED), thus suggesting a role in the pathogenesis of these tumors. Our previous study showed that ASCL1 is a regulator of the RET oncogene in AD with NED. RET is a receptor tyrosine kinase with two isoforms in humans: RET9 (short) and RET51 (long). We performed survival analysis to study implications of RET isoforms in ASCL1+ tumors and found that elevated expression of the long RET mRNA was associated with poor survival. Subsequent in vitro experiments demonstrated that treatment with EGF robustly induced phosphorylation of RET in HCC1833 and H1755 cell lines which have high endogenous levels of ASCL1 and RET but not in VMRC-LCD cell line which has high level of ASCL1 but low level of RET. EGF induced phosphorylation of RET was diminished by gefitinib and by EGFR siRNA. Immunoprecipitation results indicated direct binding between EGFR and RET in presence of EGF. Furthermore, a high throughput drug screening found 8 EGFR inhibitors that were 10 - 250 fold more cytotoxic in ASCL1+ compared with ASCL1- AD cells. These results implicate EGFR as a key regulator of RET activation in ASCL1+ AD and suggest that EGFR inhibitors may be therapeutic for this population of patients. Citation Format: Kaustubh N. Bhinge, Yang Lin, Hamed Rahi, Marie Christine Aubry, Aaron Mansfield, Irina Kovtun, Stephen Murphy, Ping Yang, Dennis Wigle, Joanne (Eunhee) Yi, Aqsa Nasir, Simone Terra, Julian Molina, George Vasmatzis, Farhad Kosari. EGFR-mediated activation of RET in ASCL1+ lung adenocarcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1129.

ABSTRACTPreservation of osteochondral allografts used for transplantation is critical to ensure favorable outcomes for patients after surgical treatment of cartilage defects. To study the biological effects of protocols currently used for cartilage storage, we investigated differences in gene expression between stored allograft cartilage and fresh cartilage from living donors using high throughput molecular screening strategies. We applied next generation RNA sequencing (RNA‐seq) and real‐time reverse transcription quantitative polymerase chain reaction (RT‐qPCR) to assess genome‐wide differences in mRNA expression between stored allograft cartilage and fresh cartilage tissue from living donors. Gene ontology analysis was used to characterize biological pathways associated with differentially expressed genes. Our studies establish reduced levels of mRNAs encoding cartilage related extracellular matrix (ECM) proteins (i.e., COL1A1, COL2A1, COL10A1, ACAN, DCN, HAPLN1, TNC, and COMP) in stored cartilage. These changes occur concomitantly with increased expression of “early response genes” that encode transcription factors mediating stress/cytoprotective responses (i.e., EGR1, EGR2, EGR3, MYC, FOS, FOSB, FOSL1, FOSL2, JUN, JUNB, and JUND). The elevated expression of “early response genes” and reduced levels of ECM‐related mRNAs in stored cartilage allografts suggests that tissue viability may be maintained by a cytoprotective program that reduces cell metabolic activity. These findings have potential implications for future studies focused on quality assessment and clinical optimization of osteochondral allografts used for cartilage transplantation. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1950–1959, 2016.