Advances in the roles of ATF4 in osteoporosis

Role and mechanisms of histone methylation in osteogenic/odontogenic differentiation of dental mesenchymal stem cells

Dental mesenchymal stem cells (DMSCs) are pivotal for tooth development and periodontal tissue health and play an important role in tissue engineering and regenerative medicine because of their multidirectional differentiation potential and self-renewal ability. The cellular microenvironment regulates the fate of stem cells and can be modified using various optimization techniques. These methods can influence the cellular microenvironment, activate disparate signaling pathways, and induce different biological effects. "Epigenetic regulation" refers to the process of influencing gene expression and regulating cell fate without altering DNA sequences, such as histone methylation. Histone methylation modifications regulate pivotal transcription factors governing DMSCs differentiation into osteo-/odontogenic lineages. The most important sites of histone methylation in tooth organization were found to be H3K4, H3K9, and H3K27. Histone methylation affects gene expression and regulates stem cell differentiation by maintaining a delicate balance between major trimethylation sites, generating distinct chromatin structures associated with specific downstream transcriptional states. Several crucial signaling pathways associated with osteogenic differentiation are susceptible to modulation via histone methylation modifications. A deeper understanding of the regulatory mechanisms governing histone methylation modifications in osteo-/odontogenic differentiation and immune-inflammatory responses of DMSCs will facilitate further investigation of the epigenetic regulation of histone methylation in DMSC-mediated tissue regeneration and inflammation. Here is a concise overview of the pivotal functions of epigenetic histone methylation at H3K4, H3K9, and H3K27 in the regulation of osteo-/odontogenic differentiation and renewal of DMSCs in both non-inflammatory and inflammatory microenvironments. This review summarizes the current research on these processes in the context of tissue regeneration and therapeutic interventions.

Ectodysplasin-A deficiency exacerbates TMJOA by upregulating ATF4/Ihh signaling in mice

OBJECTIVE

Ectodysplasin-A (EDA) has been reported to be involved in mouse condylar development, but the specific functions of EDA in maintaining homeostasis of the temporomandibular joint (TMJ) remain unclear. This study aims to explore the underlying roles and related mechanisms of EDA in temporomandibular joint osteoarthritis (TMJOA).

METHOD

The TMJOA mouse model was established by unilateral discectomy and the alteration of EDA expression was detected. EDA knockout male mice and their wild-type male littermates were used to clarify the effect of EDA on TMJOA. Mouse condylar chondrocytes were extracted to explore the potential mechanisms. The effects of local injection of supplementary EDA on condyles were also evaluated morphologically and histologically.

RESULTS

The expression of EDA was downregulated in condylar cartilage after TMJOA modeling. EDA deficiency aggravated degeneration and inflammation of condylar cartilage in TMJOA mice. In vitro studies, EDA deficiency upregulated the expression of inflammatory cytokines, while supplementary EDA exhibited anticatabolic and anti-inflammatory effects on tumor necrosis factor-α (TNFα)-treated mouse condylar chondrocytes. Mechanistically, EDA deficiency efficiently activated activating transcription factor 4 (ATF4) to upregulate Indian hedgehog (Ihh) signaling pathway and thereby aggravated the inflammation. Inhibition of ATF4 resulted in blocking of Ihh signaling. The selective pharmacological inhibition of Ihh signaling attenuated TNF-α-induced chondrocyte destruction and the release of inflammatory cytokines. Furthermore, intra-articular application of EDA significantly alleviated the osteoarthritic cartilage destruction after discectomy.

CONCLUSION

EDA deficiency aggravated TMJOA by modulating ATF4/Ihh pathway, which confirming the essential role of EDA in maintaining TMJ cartilage homeostasis and its potential application in TMJOA treatment.

The association between lipid accumulation product and osteoporosis in American adults: analysis from NHANES dataset

Background

The Lipid Accumulation Product (LAP), a novel indicator of fat accumulation, reflects the distribution and metabolic status of body fat. This study aims to evaluate the relationship between adult Americans' prevalence of osteoporosis and LAP.

Methods

This study used data from the NHANES cycles 2007-2010, 2013-2014, and 2017-2018, including 4,200 adults aged 50 and above. LAP was calculated using waist circumference and triglyceride levels, whereas osteoporosis was identified using information from dual-energy X-ray absorptiometry (DXA) assessments of bone mineral density (BMD). Restricted cubic spline (RCS) analysis was evaluated the relationship between LAP and osteoporosis. Additionally, subgroup analyses were conducted to assess the impact of demographic characteristics and health status on the relationship between LAP and osteoporosis.

Results

LAP and osteoporosis were shown to be significantly inversely correlated in the study. In the unadjusted model, the prevalence of osteoporosis and Log LAP showed a significant negative connection (OR = 0.62, 95% CI = 0.52-0.74). Osteoporosis prevalence decreased by 45% in the fully adjusted model for every unit rise in Log LAP (OR = 0.54, 95% CI = 0.44-0.66). RCS analysis revealed a nonlinear association between LAP and osteoporosis prevalence (P-non-linear = 0.0025), showing an L-shaped negative correlation. Subgroup studies showed that, regardless of age, sex, ethnicity, or health condition, there was a constant negative connection between LAP and osteoporosis.

Conclusion

According to this study, there is a substantial negative relationship between adult prevalence of osteoporosis in America and LAP. LAP is an easy-to-use and practical indication that may be very helpful in osteoporosis prevention and early detection.

Coculture of mesenchymal stem cells and macrophage: A narrative review

Stem cell transplantation is a promising treatment for repairing damaged tissues, but challenges like immune rejection and ethical concerns remain. Mesenchymal stem cells (MSCs) offer high differentiation potential and immune regulatory activity, showing promise in treating diseases such as gynecological, neurological, and kidney disorders. With scientific progress, MSC applications are overcoming traditional treatment limitations. In MSCs-macrophage coculture, MSCs transform macrophages into anti-inflammatory M2 macrophages, reducing inflammation, whereas macrophages enhance MSCs osteogenic differentiation. This coculture is vital for immune modulation and tissue repair, with models varying by contact type and dimensional arrangements. Factors such as coculture techniques and cell ratios influence outcomes. Benefits include improved heart function, wound healing, reduced lung inflammation, and accelerated bone repair. Challenges include optimizing coculture conditions. This study reviews the methodologies, factors, and mechanisms of MSC-macrophage coculture, providing a foundation for tissue engineering applications. SIGNIFICANCE STATEMENT: This review underlines the significant role of mesenchymal stem cell-macrophage coculture, providing a foundation for tissue engineering application.

Farnesol Improves Endoplasmic Reticulum Stress and Hepatic Metabolic Dysfunction Induced by Tunicamycin in Mice

Endoplasmic reticulum (ER) stress significantly affects liver metabolism, often leading to disorders such as hepatic steatosis. Tunicamycin (TM), a known ER stress inducer, is frequently used to model metabolic stress, but its specific effects on liver energy homeostasis remain unclear. This study investigates how farnesol (FOH), a natural compound with antioxidant and anti-inflammatory properties, counteracts TM-induced ER stress and its associated metabolic disruptions in the liver. Using both primary hepatocytes and a mouse model, this study demonstrates that TM treatment caused upregulation of ER stress markers, including ATF4, and disrupted genes related to lipid metabolism and gluconeogenesis. Co-treatment with FOH reduced these stress markers and restored the expression of metabolic genes. In vivo, FOH treatment alleviated oxidative stress, reduced lipid accumulation, and restored normal glycogen and lipid metabolism. Histological analysis further confirmed that FOH preserved liver architecture and minimized cellular damage. FOH also stabilized serum lipid profiles and modulated key metabolic biomarkers, suggesting its protective role against TM-induced liver injury. These findings suggest that FOH has therapeutic potential in mitigating ER stress-related metabolic dysfunctions, offering promising insights for the treatment of liver diseases linked to metabolic stress.

Impact of Different Cell Types on the Osteogenic Differentiation Process of Mesenchymal Stem Cells

The skeleton is an important organ in the human body. Bone defects caused by trauma, inflammation, tumors, and other reasons can impact the quality of life of patients. Although the skeleton has a certain ability to repair itself, the current most effective method is still autologous bone transplantation due to factors such as blood supply and defect size. Modern medicine is attempting to overcome these limitations through cell therapy, with mesenchymal stem cells (MSCs) playing a crucial role. MSCs can be extracted from different tissues, and their differentiation potential varies depending on the source. Various cells and cell secretions can influence this process. This article, based on previous research, reviews the effects of macrophages, endothelial cells (ECs), nerve cells, periodontal cells, and even some bacteria on MSC osteogenic differentiation, aiming to provide a reference for multicell coculture strategies related to osteogenesis.

Concomitant Detection of Serum Activating Transcription Factor 4 Levels and Mean Amplitude of Glycemic Excursion Is Helpful to Predict Osteoporosis in Adults With Type 2 Diabetes Mellitus

OBJECTIVES

Activating transcription factor 4 (ATF4) and mean amplitude of glycemic excursion (MAGE) have been implicated in the pathogenesis of osteoporosis (OP) and type 2 diabetes mellitus (T2DM). In this retrospective cohort study we assessed the predictive value of serum ATF4 and MAGE for occurrence of OP in individuals with T2DM.

METHODS

A total of 162 individuals with T2DM were assigned to T2DM or T2DM+OP groups. All participants underwent serum ATF4 level detection and 72-hour blood glucose monitoring (MAGE measurement). The correlations of ATF4 and MAGE with glucose and bone metabolism indicators and bone mineral density (BMD) were analyzed. A multivariate logistic regression model was developed to evaluate the correlations of ATF4 and MAGE with T2DM-associated OP. The diagnostic performance of concomitant detection of ATF4 and MAGE was assessed based on area under the receiver operating characteristic (AUC) curve.

RESULTS

Individuals with T2DM with OP had higher serum ATF4 levels and MAGE than those with T2DM only. ATF4 and MAGE correlated positively with fasting insulin, glycated hemoglobin, homeostatic model for insulin resistance assessment, beta-C-terminal crosslinking telopeptide of type I collagen, and tartrate-resistant acid phosphatase-5b, but negatively with bone alkaline phosphatase, serum procollagen type I N-propeptide, procollagen type I carboxy-terminal propeptide, and BMD. Elevated levels of ATF4 and MAGE were independent risk factors, but increased BMD at the hip, femoral neck, and lumbar spine was a protective factor for individuals with T2DM with OP. More importantly, the AUC of concomitant ATF4 and MAGE was considerably higher than that of ATF4 or MAGE alone.

CONCLUSION

Concomitant detection of ATF4 and MAGE may aid in predicting the occurrence of OP in individuals with T2DM.

YBX1 alleviates ferroptosis in osteoporosis via the ATF4/FSP1 axis in an m5C manner

BACKGROUND

Interactions between RNA-binding proteins and RNA regulate RNA transcription during osteoporosis. Ferroptosis, a programmed cell death caused by iron metabolism, plays a vital role in osteoporosis. However, the mechanisms by which RNA-binding proteins are involved in ferroptosis during osteoporosis remain unclear.

METHODS

We established an in vitro model of osteoporosis induced by D-galactose (D-gal) in MC3T3-E1 cells. Ferroptosis suppressor protein 1 (FSP1), activating transcription factor 4 (ATF4), and Y-box binding protein 1 (YBX1) knockdown MC3T3-E1 cells were generated, and their effects on ferroptosis were verified by measuring lipid reactive oxygen species levels and cellular Fe2+. Chromatin immunoprecipitation and luciferase assays were performed to confirm the binding of ATF4 to the FSP1 promoter. RNA pulldown and RNA immunoprecipitation experiments were used to determine the binding between YBX1 and ATF4 mRNA and to test the effect of YBX1 on ATF4 mRNA stability in a 5-methylcytosine (m5C)-dependent manner.

RESULTS

FSP1 or YBX1 knockdown led to a D-gal-induced increase in lipid reactive oxygen species levels and cellular Fe2+ in MC3T3-E1 cells, which was alleviated by ATF4 overexpression. ATF4 inhibits ferroptosis by binding to the FSP1 promoter. In addition, YBX1 increased ATF4 mRNA stability through m5C RNA modification and inhibited ferroptosis in MC3T3-E1 cells via the ATF4/FSP1 axis.

CONCLUSION

Our results showed that YBX1 could alleviate ferroptosis via the ATF4/FSP1 axis in an m5C-dependent manner in D-gal-induced osteoblasts, suggesting that YBX1 may be a new target for osteoporosis treatment.

An Overview of Research Advances in Oncology Regarding the Transcription Factor ATF4

This review provides a comprehensive overview of the recent advancements in research on ATF4 (Activating Transcription Factor 4) within the field of oncology. As a crucial transcription factor, ATF4 has garnered increasing attention for its role in cancer research. The review begins with an exploration of the regulatory mechanisms of ATF4, including its transcriptional control, post-translational modifications, and interactions with other transcription factors. It then highlights key research findings on ATF4's involvement in various aspects of tumor biology, such as cell proliferation, differentiation, apoptosis and survival, invasion and metastasis, and the tumor microenvironment. Furthermore, the review discusses the potential of targeting ATF4 as a novel therapeutic strategy for cancer treatment. It also explores how ATF4's interactions with existing anticancer drugs could inform the development of more effective therapeutic agents. By elucidating the role of ATF4 in tumor biology and its potential clinical applications, this review aims to provide new insights and strategies for cancer treatment.

Unraveling the Mechanism of Impaired Osteogenic Differentiation in Osteoporosis: Insights from ADRB2 Gene Polymorphism

Osteoporosis is characterized by increased resorption and decreased bone formation; it is predominantly influenced by genetic factors. G-protein coupled receptors (GPCRs) play a vital role in bone homeostasis, and mutations in these genes are associated with osteoporosis. This study aimed to investigate the impact of single nucleotide polymorphism (SNP) rs1042713 in the ADRB2 gene, encoding the beta-2-adrenergic receptor, on osteoblastogenesis. Herein, using quantitative polymerase chain reaction, western immunoblotting, immunofluorescence assays, and flow cytometry, we examined the expression of ADRB2 and markers of bone matrix synthesis in mesenchymal stem cells (MSCs) derived from osteoporosis patient (OP-MSCs) carrying ADRB2 SNP in comparison with MSCs from healthy donor (HD-MSCs). The results showed significantly reduced ADRB2 expression in OP-MSCs at both the mRNA and protein levels, alongside decreased type 1 collagen expression, a key bone matrix component. Notably, OP-MSCs exhibited increased ERK kinase expression during differentiation, indicating sustained cell cycle progression, unlike that going to HD-MSC. These results provide novel insights into the association of ADRB2 gene polymorphisms with osteogenic differentiation. The preserved proliferative activity of OP-MSCs with rs1042713 in ADRB2 contributes to their inability to undergo effective osteogenic differentiation. This research suggests that targeting genetic factors may offer new therapeutic strategies to mitigate osteoporosis progression.

Irisin: A Multifaceted Hormone Bridging Exercise and Disease Pathophysiology

The fibronectin domain-containing protein 5 (FNDC5), or irisin, is an adipo-myokine hormone produced during exercise, which shows therapeutic potential for conditions like metabolic disorders, osteoporosis, sarcopenia, obesity, type 2 diabetes, and neurodegenerative diseases, including Alzheimer's disease (AD). This review explores its potential across various pathophysiological processes that are often considered independent. Elevated in healthy states but reduced in diseases, irisin improves muscle-adipose communication, insulin sensitivity, and metabolic balance by enhancing mitochondrial function and reducing oxidative stress. It promotes osteogenesis and mitigates bone loss in osteoporosis and sarcopenia. Irisin exhibits anti-inflammatory effects by inhibiting NF-κB signaling and countering insulin resistance. In the brain, it reduces amyloid-β toxicity, inflammation, and oxidative stress, enhancing brain-derived neurotrophic factor (BDNF) signaling, which improves cognition and synaptic health in AD models. It also regulates dopamine pathways, potentially alleviating neuropsychiatric symptoms like depression and apathy. By linking physical activity to systemic health, irisin emphasizes its role in the muscle-bone-brain axis. Its multifaceted benefits highlight its potential as a therapeutic target for AD and related disorders, with applications in prevention, in treatment, and as a complement to exercise strategies.

Comprehensive Overview of Interface Strategies in Implant Osseointegration

With the improvement of implant design and the expansion of application scenarios, orthopedic implants have become a common surgical option for treating fractures and end‐stage osteoarthritis. Their common goal is rapidly forming and long‐term stable osseointegration. However, this fixation effect is limited by implant surface characteristics and peri‐implant bone tissue activity. Therefore, this review summarizes the strategies of interface engineering (osteogenic peptides, growth factors, and metal ions) and treatment methods (porous nanotubes, hydrogel embedding, and other load‐release systems) through research on its biological mechanism, paving the way to achieve the adaptation of both and coordination between different strategies. With the transition of the osseointegration stage, interface engineering strategies have demonstrated varying therapeutic effects. Especially, the activity of osteoblasts runs almost through the entire process of osseointegration, and their physiological activities play a dominant role in bone formation. Furthermore, diseases impacting bone metabolism exacerbate the difficulty of achieving osseointegration. This review aims to assist future research on osseointegration engineering strategies to improve implant‐bone fixation, promote fracture healing, and enhance post‐implantation recovery.

KPNB1-ATF4 induces BNIP3-dependent mitophagy to drive odontoblastic differentiation in dental pulp stem cells

BACKGROUND

Differentiating dental pulp stem cells (DPSCs) into odontoblasts is a critical process for tooth self-repair and dentine‒pulp engineering strategies in the clinic. However, the mechanism underlying the regulation of DPSC odontoblastic differentiation remains largely unknown. Here, we demonstrated that BCL-2 interacting protein 3 (BNIP3)-dependent mitophagy is associated with importin subunit beta-1 (KPNB1)-activating transcription factor 4 (ATF4), which promotes DPSC odontoblastic differentiation.

METHODS

The key genes involved in DPSC odontogenic differentiation were identified via bioinformatics. Stable silencing or overexpression of BNIP3 was performed to investigate its impact on DPSC differentiation in vitro (n ≥ 3). To explore the role of BNIP3 in vivo, tooth root fragments loaded with the hydrogel-transfected DPSC complex were implanted into nude mice (n ≥ 6). Dual-luciferase reporter assays and chromatin immunoprecipitation (ChIP) polymerase chain reaction (PCR) were conducted to explore the binding site of ATF4 to the BNIP3 promoter (n ≥ 3). Mitochondrial function experiments were performed to investigate the impact of ATF4-BNIP3 on mitochondria (n ≥ 3). Immunoprecipitation (IP) mass spectrometry (MS) was used to investigate the interaction between ATF4 and its binding protein, KPNB1. Plasmids containing wild-type (WT)/mutant (MUT)-nuclear localization signal (NLS) forms of ATF4 were constructed to determine the specific amino acid residues recognized by KPNB1 and their effects on DPSC odontoblastic differentiation (n ≥ 3).

RESULTS

Compared with those in the control group, the levels of autophagy and mitophagy, especially BNIP3-dependent mitophagy, were greater in the DPSC odontoblastic differentiation group (P < 0.05). Genetic silencing or overexpression of BNIP3 demonstrated that BNIP3 expression was positively correlated with the transition of DPSCs into odontoblasts both in vitro and in vivo (P < 0.05). ATF4 regulates the expression of BNIP3 by directly binding to approximately -1292 to -1279 bp and approximately -1185 to -1172 bp within the BNIP3 promoter region, which is associated with mitophagy and mitochondrial reactive oxygen species (mtROS) levels (P < 0.05). Moreover, ATF4 increased mitophagy, mitochondrial function, and cell differentiation potential via BNIP3 (P < 0.05). Mechanistically, KPNB1 is a novel interacting protein of ATF4 that specifically recognizes amino acids (aa) 280-299 within ATF4 to control its translocation into the nucleus and subsequent transcription and differentiation processes (P < 0.05).

CONCLUSIONS

We reported that the critical role of KPNB1/ATF4/BNIP3 axis-dependent mitophagy could provide new cues for the regeneration of the dental pulp‒dentin complex in DPSCs.

Natural Compounds for Bone Remodeling: Targeting osteoblasts and relevant signaling pathways

In the process of bone metabolism and bone remodeling, bone marrow mesenchymal stem cells (BM-MSCs) differentiate into osteoblasts (OBs) under certain conditions to enable the formation of new bone, and normal bone reconstruction and pathological bone alteration are closely related to the differentiation and proliferation functions of OBs. Osteogenic differentiation of BM-MSCs involves multiple signaling pathways, which function individually but interconnect intricately to form a complex signaling regulatory network. Natural compounds have fewer adverse effects than chemically synthesized drugs, optimize bone health, and are more suitable for long-term use. In this paper, we focus on OBs, summarize the current research progress of signaling pathways related to OBs differentiation, and review the molecular mechanisms by which chemically synthesized drugs with potential anti-osteoporosis properties regulate OBs-mediated bone formation.

Wnt/β-catenin signaling pathway: proteins' roles in osteoporosis and cancer diseases and the regulatory effects of natural compounds on osteoporosis

Osteoblasts are mainly derived from mesenchymal stem cells in the bone marrow. These stem cells can differentiate into osteoblasts, which have the functions of secreting bone matrix, promoting bone formation, and participating in bone remodeling. The abnormality of osteoblasts can cause a variety of bone-related diseases, including osteoporosis, delayed fracture healing, and skeletal deformities. In recent years, with the side effects caused by the application of PTH drugs, biphosphonate drugs, and calmodulin drugs, people have carried out more in-depth research on the mechanism of osteoblast differentiation, and are actively looking for natural compounds for the treatment of osteoporosis. The Wnt/β-catenin signaling pathway is considered to be one of the important pathways of osteoblast differentiation, and has become an important target for the treatment of osteoporosis. The Wnt/β-catenin signaling pathway, whether its activation is enhanced or its expression is weakened, will cause a variety of diseases including tumors. This review will summarize the effect of Wnt/β-catenin signaling pathway on osteoblast differentiation and the correlation between the related proteins in the pathway and human diseases. At the same time, the latest research progress of natural compounds targeting Wnt/β-catenin signaling pathway against osteoporosis is summarized.

Current insights and future directions of LncRNA Morrbid in disease pathogenesis

Non-coding RNAs have emerged as important regulators of gene expression and contributors to many diseases. LncRNA Morrbid, a long non-coding RNA, has been widely studied in recent years. Current literature reports that lncRNA Morrbid is involved in various diseases such as tumors, cardiovascular diseases, inflammatory diseases and metabolic disorder. However, controversial conclusions exist in current studies. As a potential therapeutic target, it is necessary to comprehensively review the current evidence. In this work, we carefully review the literature on Morrbid and discuss each of the hot topics related to lncRNA Morrbid.

Sil1-deficient fibroblasts generate an aberrant extracellular matrix leading to tendon disorganisation in Marinesco-Sjögren syndrome

BACKGROUND

Marinesco-Sjögren syndrome (MSS) is an autosomal recessive neuromuscular disorder that arises in early childhood and is characterized by congenital cataracts, myopathy associated with muscle weakness, and degeneration of Purkinje neurons leading to ataxia. About 60% of MSS patients have loss-of-function mutations in the SIL1 gene. Sil1 is an endoplasmic reticulum (ER) protein required for the release of ADP from the master chaperone Bip, which in turn will release the folded proteins. The expression of non-functional Sil1 leads to the accumulation of unfolded proteins in the ER and this triggers the unfolded protein response (UPR). A dysfunctional UPR could be a key element in the pathogenesis of MSS, although our knowledge of the molecular pathology of MSS is still incomplete.

METHODS

RNA-Seq transcriptomics was analysed using the String database and the Ingenuity Pathway Analysis platform. Fluorescence confocal microscopy was used to study the remodelling of the extracellular matrix (ECM). Transmission electron microscopy (TEM) was used to reveal the morphology of the ECM in vitro and in mouse tendon.

RESULTS

Our transcriptomic analysis, performed on patient-derived fibroblasts, revealed 664 differentially expressed (DE) transcripts. Enrichment analysis of DE genes confirmed that the patient fibroblasts have a membrane trafficking issue. Furthermore, this analysis indicated that the extracellular space/ECM and the cell adhesion machinery, which together account for around 300 transcripts, could be affected in MSS. Functional assays showed that patient fibroblasts have a reduced capacity of ECM remodelling, reduced motility, and slower spreading during adhesion to Petri dishes. TEM micrographs of negative-stained ECM samples from these fibroblasts show differences of filaments in terms of morphology and size. Finally, structural analysis of the myotendinous junction of the soleus muscle and surrounding regions of the Achilles tendon revealed a disorganization of collagen fibres in the mouse model of MSS (woozy).

CONCLUSIONS

ECM alterations can affect the proper functioning of several organs, including those damaged in MSS such as the central nervous system, skeletal muscle, bone and lens. On this basis, we propose that aberrant ECM is a key pathological feature of MSS and may help explain most of its clinical manifestations.

Effects of Different No-Ozone Cold Plasma Treatment Methods on Mouse Osteoblast Proliferation and Differentiation

Background and Objectives: Enhanced osteoblast differentiation may be leveraged to prevent and treat bone-related diseases such as osteoporosis. No-ozone cold plasma (NCP) treatment is a promising and safe strategy to enhance osteoblast differentiation. Therefore, this study aimed to determine the effectiveness of direct and indirect NCP treatment methods on osteoblast differentiation. Mouse osteoblastic cells (MC3T3-E1) were treated with NCP using different methods, i.e., no NCP treatment (NT group; control), direct NCP treatment (DT group), direct NCP treatment followed by media replacement (MC group), and indirect treatment with NCP-treated media only (PAM group). Materials and Methods: The MC3T3-E1 cells were subsequently assessed for cell proliferation, alkaline phosphatase (ALP) activity, calcium deposition, and ALP and osteocalcin mRNA expression using real-time polymerase chain reaction. Results: Cell proliferation significantly increased in the NCP-treated groups (DT and PAM; MC and PAM) compared to the NT group after 24 h (p < 0.038) and 48 h (p < 0.000). ALP activity was increased in the DT and PAM groups at 1 week (p < 0.115) and in the DT, MC, and PAM groups at 2 weeks (p < 0.000) compared to the NT group. Calcium deposition was higher in the NCP-treated groups than in NT group at 2 and 3 weeks (p < 0.000). ALP mRNA expression peaked in the MC group at 2 weeks compared to the NP group (p < 0.014). Osteocalcin mRNA expression increased in the MC group at 2 weeks (p < 0.000) and was the highest in the PAM group at 3 weeks (p < 0.000). Thus, the effects of direct (DT and MC) and indirect (PAM) treatment varied, with MC direct treatment showing the most significant impact on osteoblast activity. Conclusions: The MC group exhibited enhanced osteoblast differentiation, indicating that direct NCP treatment followed by media replacement is the most effective method for promoting bone formation.

Harnessing extracellular vesicles-mediated signaling for enhanced bone regeneration: novel insights into scaffold design

The increasing prevalence of bone replacements and complications associated with bone replacement procedures underscores the need for innovative tissue restoration approaches. Existing synthetic grafts cannot fully replicate bone vascularization and mechanical characteristics. This study introduces a novel strategy utilizing pectin, chitosan, and polyvinyl alcohol to create interpenetrating polymeric network (IPN) scaffolds incorporated with extracellular vesicles (EVs) isolated from human mesenchymal stem cells (hMSCs). We assess the osteointegration and osteoconduction abilities of these modelsin vitrousing hMSCs and MG-63 osteosarcoma cells. Additionally, we confirm exosome properties through Transmission Electron Microscopy (TEM), immunoblotting, and Dynamic Light Scattering (DLS).In vivo, chick allantoic membrane assay investigates vascularization characteristics. The study did not includein vivoanimal experiments. Our results demonstrate that the IPN scaffold is highly porous and interconnected, potentially suitable for bone implants. EVs, approximately 100 nm in size, enhance cell survival, proliferation, alkaline phosphatase activity, and the expression of osteogenic genes. EVs-mediated IPN scaffolds demonstrate promise as precise drug carriers, enabling customized treatments for bone-related conditions and regeneration efforts. Therefore, the EVs-mediated IPN scaffolds demonstrate promise as precise carriers for the transport of drugs, allowing for customized treatments for conditions connected to bone and efforts in regeneration.

ATF4 inhibits tumor development and mediates p-GCN2/ASNS upregulation in colon cancer

Colon cancer (CC) is a highly malignant tumor with a high incidence and poor prognosis. This study aimed to explore the function and molecular mechanisms of activating transcription factor 4 (ATF4) in CC. The expression levels of ATF4, GCN2, and ASNS in CC tissues were measured using immunohistochemistry (IHC) and reverse transcription quantitative PCR (RT-qPCR). Cell counting kit-8 (CCK-8), clone formation, transwell, and flow cytometry assays were conducted to assess cell viability, clonogenicity, migration, invasion, cell cycle, and apoptosis, respectively, in the ATF4 knockdown and overexpression SW480 cell lines. The effect of ATF4 on the expression of GCN2 and ASNS was detected using RT-qPCR, Chip-qPCR, and western blotting. ATF4, GCN2, and ASNS were expressed at low levels in CC tissues, and all had a significant negative correlation with tumor diameter. ATF4 knockdown promoted cell proliferation, invasion, and S-phase cell cycle and inhibited apoptosis in SW480 cells. In contrast, ATF4 overexpression had the opposite effect. Furthermore, ATF4 overexpression enhanced ATF4 binding to the ASNS promoter region. ATF4 knockdown significantly inhibited the expression of p-GCN2 and ASNS, whereas ATF4 overexpression significantly upregulated their expression. ATF4 inhibited CC cell viability, clone formation ability, migration, and invasion and promoted apoptosis, possibly by regulating the expression of p-GCN2 and ASNS. Our study provides a novel potential therapeutic target for the treatment of CC.

In vitro determination of osteo-adipogenic lineage choice of bone marrow stromal/stem cells (BMSCs)

Bone marrow stromal/stem cells (BMSCs) are primitive and heterogeneous cells that can be differentiated into osteoblasts, adipocytes and other subsets. Their bone-fat lineage commitment is responsible for the homeostasis of bone marrow microenvironment. However, there are little effective methods and evidence to simultaneously visualise the lineage commitment of BMSCs. Here we provide a bivalent differentiation medium that can enable BMSCs differentiation into osteoblasts and adipocytes in vitro, and establish a method to simultaneously distinguish osteoblasts or adipocytes from the heterogeneous BMSCs based on Alizarin red S and Oil red O staining, which have been used for detection of specific mineralized nodules and lipid droplets, respectively. This assay provides a specifically simple but effective and low-cost method to evaluate the efficiency of osteo-adipogenic (OA) allocation of BMSCs.►Researchers can utilize the bivalent differentiation medium to evaluate the efficiency of osteogenic and adipogenic differentiation of BMSCs in vitro.

A deep insight into ferroptosis in lung disease: facts and perspectives

In the last decade, ferroptosis has received much attention from the scientific research community. It differs from other modes of cell death at the morphological, biochemical, and genetic levels. Ferroptosis is mainly characterized by non-apoptotic iron-dependent cell death caused by iron-dependent lipid peroxide excess and is accompanied by abnormal iron metabolism and oxidative stress. In recent years, more and more studies have shown that ferroptosis is closely related to the occurrence and development of lung diseases. COPD, asthma, lung injury, lung fibrosis, lung cancer, lung infection and other respiratory diseases have become the third most common chronic diseases worldwide, bringing serious economic and psychological burden to people around the world. However, the exact mechanism by which ferroptosis is involved in the development and progression of lung diseases has not been fully revealed. In this manuscript, we describe the mechanism of ferroptosis, targeting of ferroptosis related signaling pathways and proteins, summarize the relationship between ferroptosis and respiratory diseases, and explore the intervention and targeted therapy of ferroptosis for respiratory diseases.