Iron regulates chondrocyte phenotype in haemophilic cartilage through the PTEN/PI3 K/AKT/FOXO1 pathway.

OBJECTIVE: Our previous study demonstrated that iron overload could lead to haemophilic cartilage destruction by changing chondrocyte phenotype. This change was caused by iron's effect on chondrocyte expression of FGF23 and SOX9, in addition to iron-induced chondrocyte apoptosis and cartilage extracellular matrix degradation. However, the underlying mechanisms remain unclear. This study aimed to determine the mechanism by which iron influences chondrocyte phenotype in the pathogenesis of haemophilic cartilage destruction. METHODS: The expression of the PTEN/PI3K/AKT/FOXO1 signal pathway in the articular cartilage of patients with haemophilic arthritis (HA) or osteoarthritis (OA) was determined using western blot (WB). Additionally, we quantified the expression of iron-induced PTEN, PI3K, p-PI3K, AKT, p-AKT, FOXO1, and p-FOXO1 in primary human normal chondrocyte cells (HUM-iCell-s018) using WB. RESULTS: We found that compared to that in patients with OA, the expression of PTEN, PI3K, AKT, and FOXO1 in the articular cartilage of patients with HA was up-regulated, while the expression of p-PI3K, p-AKT, and p-FOXO1 was down-regulated. Additionally, iron increased the expression of PTEN, PI3K, AKT, and FOXO1 and suppressed that of p-PI3K, p-AKT, and p-FOXO1 in chondrocytes in a dose-dependent manner. CONCLUSIONS: Our findings demonstrated that iron was involved in the pathogenesis of haemophilic cartilage destruction by affecting chondrocyte phenotype through the inhibition of the PTEN/PI3K/AKT/FOXO1 pathway.

Small Extracellular Vesicles Derived From MSCs Have Immunomodulatory Effects to Enhance Delivery of ASO-210 for Psoriasis Treatment.

Mesenchymal stem cells (MSCs) have been increasingly used for treating autoimmune diseases due to their immune modulation functions, but inefficient homing to the target tissue and safety issues limits their wide application. Recently, increasing studies demonstrate small extracellular vesicles (sEVs) as key mediators of MSCs to exert their immunomodulatory effects. In this study, we found that sEVs derived from human umbilical cord MSCs stimulated by IFN-γ (IFNγ-sEVs) inhibited proliferation and activation of peripheral blood mononuclear cells and T cells in vitro. Furthermore, we confirmed that IFNγ-sEVs reduced psoriasis symptoms including thickness, erythema, and scales of skin lesions; exhausted Th17 cells, increased Th2 cells; and reduced enrichment of inflammatory cytokines such as IL-17A, IFN-γ, IL-6, and TNF-α in both spleen and skin lesions in vivo. Importantly, IFNγ-sEVs significantly improved the delivery efficiency and stability of ASO-210, the antisense oligonucleotides of miR-210 block the immune imbalance and subsequent psoriasis development. Our results reveal MSC-sEVs as promising cell-free therapeutic agents and ideal delivery vehicles of antisense oligonucleotides for psoriasis treatment.

4-Hexylresorcinol inhibits osteoclastogenesis by suppressing the NF-κB signaling pathway and reverses bone loss in ovariectomized mice.

4-Hexylresorcinol (4HR) is a small organic compound that is widely used as an antiseptic and antioxidant. In the present study, its role in osteoclastogenesis was investigated. Bone marrow-derived macrophages from mice were used to examine the role of 4HR in osteogenesis. An ovariectomy (OVX) mouse model was constructed to examine the effect of 4HR in vivo, followed by hematoxylin and eosin and tartrate resistant acid phosphatase staining. In the present study, 4HR effectively suppressed receptor activator of NF-κB ligand-induced osteoclastogenesis in a dose-dependent manner. 4HR was also found to significantly suppress the expression of osteoclast (OC)-specific markers, including tartrate-resistant acid phosphatase, cathepsin K, nuclear factor of activated T-cell cytoplasmic 1 and c-Fos in the presence of RANKL in BMMs. Furthermore, 4HR inhibited osteoclastogenesis by inhibiting the activation of the NF-κB signaling pathway in BMMs. Consistent with the in vitro results, 4HR effectively ameliorated OVX-induced bone loss and markedly reduced OC number in the proximal tibia in vivo. In conclusion, the present results suggested that 4HR inhibited osteoclastogenesis in vitro and rescued bone loss in vivo, suggesting that 4HR may serve as a novel therapeutic agent for osteoporosis treatment.

CRISPR-assisted detection of RNA-protein interactions in living cells.

We have developed CRISPR-assisted RNA-protein interaction detection method (CARPID), which leverages CRISPR-CasRx-based RNA targeting and proximity labeling to identify binding proteins of specific long non-coding RNAs (lncRNAs) in the native cellular context. We applied CARPID to the nuclear lncRNA XIST, and it captured a list of known interacting proteins and multiple previously uncharacterized binding proteins. We generalized CARPID to explore binders of the lncRNAs DANCR and MALAT1, revealing the method's wide applicability in identifying RNA-binding proteins.

Methods for PTEN in Stem Cells and Cancer Stem Cells.

PTEN (phosphatase and tensin homologue) is the first tumor suppressor identified to have phosphatase activity and its gene is the second most frequently deleted or mutated tumor-suppressor gene associated with human cancers. Germline PTEN mutations are the cause of three inherited autosomal dominant disorders. Phosphatidylinositol 3,4,5,-triphosphate (PIP3), the product of the PI3 kinase, is one of the key intracellular targets of PTEN's phosphatase activity, although PTEN's phosphatase-independent activities have also been identified. PTEN is critical for stem cell maintenance, which contributes to its controlled tumorigenesis. PTEN loss leads the development of cancer stem cells (CSCs) that share properties with somatic stem cells, including the capacity for self-renewal and multi-lineage differentiation. Methods to isolate and functionally test stem cells and CSCs are important for understanding PTEN functions and the development of therapeutic approaches to target CSCs without having adverse effects on normal stem cells. Here, we describe protocols for the isolation and functional analysis of PTEN deficient embryonic stem cells, hematopoietic stem cells and leukemia-initiating cells (LICs), neural stem cells, and prostate stem cells and CSCs.