The Effects And Mechanisms Of Progranulin In Cartilage Degeneration Of ONFG And Osteosarcoma

Osteonecrosis of the femoral head(ONFH)is a devastating disease and an increasing health problem,worldwide.The increasing prevalence may be due to various risks factors,including trauma,excessive steroid use,alcoholism,damage from radiation,sickle cell anemia,and Gaucher's disease.Osteonecrosis of the femoral head is often progressive,necessitating multiple procedures and often culminating in arthroplasty.To date,the pathologic process of ONFH is still unclear,but it has been reported that it starts with necrosis in femoral head bone tissue,which is thought to be a result of the blood circulation disturbance to the femoral head.The pathogenesis of ONFH involves both osteogenesis and osteoclastic activity,and numerous inflammatory mediators are produced.At present,the study of femoral head necrosis has penetrated into the molecular and gene levels.It has been found that the expression of various inflammatory molecules increases,and the inflammatory factors and the contents of cartilage degradation products in hip joint fluid are also increased.In the process of necrosis of the femoral head,the entire hip joint has pathological changes and there is a clear inflammatory response.We found that cartilage degeneration appeared in the early stage of the femoral head necrosis,and we believed that the cartilage degeneration played a important role in the process of femoral head necrosis.However,the causes and mechanisms of cartilage degradation are not clear,and the study of cartilage inflammation in the process of femoral head necrosis is still less.Osteosarcoma,the most common primary malignant bone tumor,usually arises in the metaphysis of long bones such as the distal femur,proximal tibia,and proximal humerus during the second decade of life.Overall,osteosarcoma has a moderate incidence rate,with 6 to 8 new cases per million worldwide each year.In recent years,the emergence of neoadjuvant chemotherapy dramatically increased the five-year survival rate.Although long-term survival in localized osteosarcoma has improved to about 60%during the 1960s and 1970s,long-term survival in both recurrent and metastatic osteosarcoma has stagnated in the past several decades.Thus,innovative drugs and approaches are needed to further improve outcomes in osteosarcoma patients.Growth factors and their receptor-mediated signaling cascades are the major regulators of tumor progression after tumor initiation.Progranulin,as an autocrine growth factor,has a variety of biological functions,expressed in a variety of tissues such as epithelial tissue,nerve tissue,cartilage tissue and a variety of tumor tissue,and was confirmed to play an important role in the development,differentiation and proliferation of cartilage.Progranulin is highly expressed in a variety of tumor tissues and plays an important role in the formation,development and metastasis of tumors.PGRN functions by directly binding to tumor necrosis factor receptors(TNFR)and counteracting the TNF-mediated inflammatory signaling pathway.Recent studies have proved that PGRN plays an important role in chondrocyte proliferation,differentiation,and endochondral ossification development.During pathogenic process of OA,PGRN is expressed in human knee articular cartilage.It is still unclear if PGRN is also expressed in the articular cartilage of ONFH and Osteosarcoma and if it plays a role in the pathogenesis of ONFH and Osteosarcoma.The aim of this study was to investigate the expression of Progranulin in the cartilage of ONFH and osteosarcoma,and to study its roles and mechanisms in the progress of femoral head necrosis and osteosarcoma,and to find new diagnostic and therapeutic targets to improve the patient's prognosis.This study was divided into two parts:The first part was to study the roles and mechanisms of Progranulin in cartilage degeneration of ONFH;The second part aimed to study the expression of Progranulin in osteosarcoma and its roles and mechanisms in the proliferition,invasion and migration of osteosarcoma cells.Part 1 The Effects and Mechanisms of Progranullin in cartilage degeneration of ONFHObjective The aim of this study was to investigate progranulin(PGRN)expression and its effect in cartilage degradation and in the pathogenesis of osteonecrosis of the femoral head(ONFH).Methods Cartilage specimens were obtained from ONFH and FNF patients and PGRN expression was analyzed by immunohistochemistry,western blot analysis,and RT-PCR.Peripheral blood PGRN level was detected by ELISA.Additionally,primary chondrocytes were cultured and treated with PGRN.Next,the expression of aggrecan and collagen ? and the activation of ERK1/2 were detected.Results We observed that the expression of PGRN was significantly up-regulated in ONFH patients' articular cartilage,and recombinant PGRN could promote expression of aggrecan and collagen II and the activation of ERK1/2.Conclusions Collectively,PGRN can improve chondrocyte anabolism and perform a therapeutic role in the pathogenesis of ONFH.This study helps to elucidate the pathogenesis of ONFH and presents PGRN as a potential target for the treatment of ONFH.Part 2 The Effects and Mechanisms of Progranullin in OsteosarcomaBackground Progranulin(PGRN)is an autocrine growth factor with tumorigenic roles in various tumors.Osteosarcoma is the most frequent malignant primary bone tumor and a main cause of tumor-related death in children and adolescents.Little is known about the role of PGRN in Osteosarcoma.Objective This study aimed to determine the expression of PGRN in osteosarcoma cells,patient serums and tissues,and the role and molecular mechanism of PGRN in osteosarcoma cell proliferation,invasion and migration.Methods We used immunohistochemistry,western-blot,RT-PCR,cellular immunofluorescence staining and ELISA assays to determine the expression levels of PGRN in osteosarcoma tissues,patient serums and osteosarcoma cell lines.The effects of PGRN on proliferation,invasion and migration of osteosarcoma cells were detected by CCK-8 assay,Cell cycle detection,wound healing assay and transwell test respectively.Additionally,the expression of MMP-2,as well as the activation of Akt and mammalian target of rapamycin(mTOR)signaling pathway was detected after treatment of PGRN or PGRN suppressed.Meanwhile we assessed the role of PGRN-mediated signaling pathway in the osteosarcoma cells with specific inhibitors.Results We found that expression of PGRN was up-regulated in osteosarcoma patient serums and tissues.PGRN could stimulate expression of MMP-2 and promote osteosarcoma cells proliferation and migration through the activation of Akt and mTOR signaling pathway.Interference of PGRN expression in osteosarcoma cells decreased cell proliferation,migration,and invasion in vitro.Conclusion Collectively,This study provides new insight into the effect of PGRN on osteosarcoma.Our results suggested that PGRN could be used as both a diagnostic biomarker and a potential target for the treatment of Osteosarcoma.