The Potential Roles of Ferroptosis in Pathophysiology and Treatment of Musculoskeletal Diseases—Opportunities, Challenges, and Perspectives

Human umbilical cord mesenchymal stem cell-derived exosomes promote osteogenesis in glucocorticoid-induced osteoporosis through PI3K/AKT signaling pathway-mediated ferroptosis inhibition

Glucocorticoid-induced osteoporosis (GIOP), the most common cause of secondary osteoporosis, is characterized by significant bone loss, decreased bone quality, and increased fracture risk. The current treatments for GIOP have several drawbacks. Exosomes are vital for cellular processes. However, very few studies have focused on using human umbilical cord mesenchymal stem cell-derived exosomes (hUCMSC-EXOs) for GIOP treatment. In vitro and in vivo dexamethasone was used to evaluate the therapeutic effects of hUCMSC-EXOs on GIOP. CCK-8 and EdU assays were used to evaluate cell viability and proliferation, respectively. We conducted an alkaline phosphatase activity assay, alizarin red staining, Western blotting, and real-time PCR to detect the effect on osteogenesis. TMT-labeled quantitative proteomic and bioinformatic analyses were performed. Furthermore, we performed Western blotting, immunofluorescence, reactive oxygen species assays, and lipid peroxidation assays to investigate the regulatory mechanism by which hUCMSC-EXOs affect cell proliferation and osteogenic differentiation. The in vivo effects of hUCMSC-EXOs were evaluated using micro-CT, hematoxylin, and eosin staining, and immunohistochemical staining. We found that hUCMSC-EXOs reversed the inhibitory effects of glucocorticoids on human bone marrow stromal cell (hBMSC) proliferation and osteogenic differentiation and demonstrated that hUCMSC-EXOs reversed GIOP via the PI3K/AKT signaling pathway, inhibiting lipid peroxidation in vitro and in vivo. HUCMSC-EXOs promote hBMSC osteogenesis through the PI3K/AKT signaling pathway, inhibit ferroptosis, and have therapeutic potential for GIOP in mice.

Exploration and breakthrough in the mode of intervertebral disc cell death may lead to significant advances in treatments for intervertebral disc degeneration

Low back pain caused by intervertebral disc degeneration (IDD) has emerged as a significant global public health concern, with far-reaching consequences for patients' quality of life and healthcare systems. Although previous research have revealed that the mechanisms of intervertebral disc cell apoptosis, pyroptosis and necroptosis can aggravate IDD damage by mediating inflammation and promoting extracellular matrix degradation, but they cannot explain the connection between different cell death mechanisms and ion metabolism disorders. The latest study shows that cell death mechanisms such as cellular senescence, ferroptosis, and cuproptosis, and PANopotosis have similar roles in the progression of intervertebral disc degeneration, but not exactly the same damage mechanism. This paper summarizes the effects of various cell death patterns on the disease progression of IDD, related molecular mechanisms and signaling pathways, providing new perspectives and potential clinical intervention strategies for the prevention and treatment of IDD.

An update on the role of ferroptosis in the pathogenesis of osteoporosis

Ferroptosis is a novel form of programmed cell death, distinguished from apoptosis, autophagy, and programmed necrosis and has received much attention since it was defined in 2012. Ferroptotic cells physiologically exhibit iron metabolism dysregulation, oxidative stress, and lipid peroxidation. Morphologically, they show plasma membrane disruption, cytoplasmic swelling, and mitochondrial condensation. Osteoporosis is taken more and more seriously as the proportion of the aging population continues to increase globally. Interestingly, ferroptosis has been demonstrated to be involved in the development and progression of osteoporosis in many extant studies. The review summarizes iron metabolism, lipid peroxidation, and the different regulatory signals in ferroptosis. Changes in signaling mechanisms within osteoblasts, osteoclasts, and osteocytes after ferroptosis occur are explained here. Studies showed ferroptosis play an important role in different osteoporosis models (diabetes osteoporosis, postmenopausal osteoporosis, glucocorticoid-induced osteoporosis). Inhibitors and EC (Exos) targeting ferroptosis could ameliorate bone loss in osteoporotic mice by protecting cells against lipid peroxidation. Shortly, we hope that more effective and appropriate clinical therapy means will be utilized in the treatment of osteoporosis.

Botulinum toxin A attenuates osteoarthritis development via inhibiting chondrocyte ferroptosis through SLC7Al1/GPX4 axis

Osteoarthritis (OA) is a prevalent joint degenerative disease, resulting in a significant societal burden. However, there is currently a lack of effective treatment option available. Previous studies have suggested that Botulinum toxin A (BONT/A), a macromolecular protein extracted from Clostridium Botulinum, may improve the pain and joint function in OA patients, but the mechanism remains elusive. This study was to investigate the impact and potential mechanism of BONT/A on OA in vivo and in vitro experiment. LPS increased the levels of ROS, Fe2+and Fe3+, as well as decreased GSH levels, the ratio of GSH / GSSH and mitochondrial membrane potential. It also enhanced the degeneration of extracellular matrix (ECM) and altered the ferroptosis-related protein expression in chondrocytes. BONT/A rescued LPS-induced decrease in collagen type II (Collagen II) expression and increase in matrix metalloproteinase 13 (MMP13), mitigated LPS-induced cytotoxicity in chondrocytes, abolished the accumulation of ROS and iron, upregulated GSH and the ratio of GSH/ GSSH, improved mitochondrial function, and promoted SLC7A11/GPX4 anti-ferroptosis system activation. Additionally, intra-articular injection of BONT/A inhibited the degradation of cartilage in OA model rats. This chondroprotective effect of BONT/A was reversed by erastin (a classical ferroptosis agonist) and enhanced by liproxstatin-1 (a classic ferroptosis inhibitor). Our research confirms that BONT/A alleviates the OA development by inhibiting the ferroptosis of chondrocytes, which revealed to be a potential therapeutic mechanism for BONT/A treating the OA.

Therapeutic targets and potential delivery systems of melatonin in osteoarthritis

Osteoarthritis (OA) is a highly prevalent age-related musculoskeletal disorder that typically results in chronic pain and disability. OA is a multifactorial disease, with increased oxidative stress, dysregulated inflammatory response, and impaired matrix metabolism contributing to its onset and progression. The neurohormone melatonin, primarily synthesized by the pineal gland, has emerged as a promising therapeutic agent for OA due to its potential to alleviate inflammation, oxidative stress, and chondrocyte death with minimal adverse effects. The present review provides a comprehensive summary of the current understanding regarding melatonin as a promising pharmaceutical agent for the treatment of OA, along with an exploration of various delivery systems that can be utilized for melatonin administration. These findings may provide novel therapeutic strategies and targets for inhibiting the advancement of OA.

Global research landscape on the crosstalk between ferroptosis and musculoskeletal diseases: A bibliometric and visualized analysis

Over the past 11 years, mounting evidence has suggested a significant association between ferroptosis and the development and progression of musculoskeletal (MSK) diseases, such as osteoporosis and osteoarthritis. However, a comprehensive bibliometric analysis summarizing the relationship between ferroptosis and MSK diseases is currently lacking. The present study collected articles and reviews on the topic of ferroptosis in MSK diseases. The data were collected from January 1st, 2012 to June 30th, 2023 by screening the Web of Science database. Various tools, including VOSviewer, CiteSpace, Pajek, the R package, and others, were used to conduct bibliometric and visualization analyses. Notably, China, the USA, and Italy emerged as primary contributors, jointly accounting for over 80 % of published documents, thereby shaping research in this domain. Among the diverse institutions, Shanghai Jiao Tong University, Soochow University, and Huazhong University of Science and Technology displayed the highest productivity levels. The most prolific authors include Sun Kai, Shang Peng, and Jing Xingzhi. Oxidative Medicine and Cellular Longevity stood out with the largest number of publications in this area. The five most significant disorders in this field are bone fractures, osteosarcoma, bone neoplasms, joint diseases, and osteoporotic fractures. This study represents an inaugural comprehensive bibliometric analysis, presenting a holistic view of the knowledge framework and developmental patterns in ferroptosis concerning MSK diseases over the previous eleven years. This information can aid researchers in acquiring a thorough grasp of this domain and offer invaluable insights for forthcoming explorations.