Osteopontin-induced lncRNA HOTAIR expression is involved in osteoarthritis by regulating cell proliferation

LncRNA HOX transcript antisense RNA mediates hyperglycemic-induced injury in the renal tubular epithelial cell via the miR-126-5pAkt axis

OBJECTIVE

To investigate the involvement of HOX transcript antisense RNA (HOTAIR) in the injury of renal tubular epithelial cells induced by high glucose. Results: In high glucose-induced HK-2 cells, the expression of HOTAIR was upregulated, resulting in suppressed cell proliferation. Meanwhile, HOTAIR upregulates the expression of pro-apoptotic proteins Bax and cleaved caspase-3, while downregulating the expression of the anti-apoptotic protein Bcl-2. Luciferase reporter assays revealed that HOTAIR could target miR-126-5p. Additionally, it was found that the PI3K/Akt signaling pathway serves as a downstream target of miR-126-5p. Knockdown of HOTAIR relieved apoptosis, whereas further inhibition of miR-126-5p led to apoptosis in HK-2 cells. Conclusions: HOTAIR plays a regulatory role in mediating high glucose-induced injuries in HK-2 cells, specifically affecting apoptosis and cell viability, via the miR-126-5p/PI3K/Akt signaling pathway.

The emerging role of lncRNAs in osteoarthritis development and potential therapy

Osteoarthritis impairs the functions of various joints, such as knees, hips, hands and spine, which causes pain, swelling, stiffness and reduced mobility in joints. Multiple factors, including age, joint injuries, obesity, and mechanical stress, could contribute to osteoarthritis development and progression. Evidence has demonstrated that genetics and epigenetics play a critical role in osteoarthritis initiation and progression. Noncoding RNAs (ncRNAs) have been revealed to participate in osteoarthritis development. In this review, we describe the pivotal functions and molecular mechanisms of numerous lncRNAs in osteoarthritis progression. We mention that long noncoding RNAs (lncRNAs) could be biomarkers for osteoarthritis diagnosis, prognosis and therapeutic targets. Moreover, we highlight the several compounds that alleviate osteoarthritis progression in part via targeting lncRNAs. Furthermore, we provide the future perspectives regarding the potential application of lncRNAs in diagnosis, treatment and prognosis of osteoarthritis.

Single-cell RNA sequencing reveals distinct chondrocyte states in femoral cartilage under weight-bearing load in Rheumatoid arthritis

Introduction

Rheumatoid arthritis (RA) is a common autoimmune joint disease, the pathogenesis of which is still unclear. Cartilage damage is one of the main manifestations of the disease. Chondrocytes are the main functional component of articular cartilage, which is relevant to disease progression. Mechanical loading affects the structure and function of articular cartilage and chondrocytes, but the effect of weight bearing on chondrocytes in rheumatoid arthritis is still unclear.

Methods

In this paper, single-cell RNA sequencing (scRNA-seq) was performed on collected cartilage from the weight-bearing region (Fb group) and non-weight-bearing region (Fnb group) of the femur, and the differences between the Fb and Fnb groups were analyzed by cell type annotation, pseudotime analysis, enrichment analysis, cell interactions, single-cell regulatory network inference and clustering (SCENIC) for each cell type.

Results

A total of 87,542 cells were analyzed and divided into 9 clusters. Six chondrocyte subpopulations were finally identified by cellular annotation, and two new chondrocyte subtypes were annotated as immune-associated chondrocytes. The presence of each chondrocyte subpopulation and its distribution were verified using immunohistochemical staining (IHC). In this study, the atlas of femoral cartilage in knee rheumatoid arthritis and 2 new immune-related chondrocytes were validated using scRNA-seq and IHC, and chondrocytes in the weight-bearing and non-weight-bearing regions of the femur were compared. There might be a process of macrophage polarization transition in MCs in response to mechanical loading, as in macrophages.

Conclusion

Two new immune-associated chondrocytes were identified. MCs have contrasting functions in different regions, which might provide insight into the role of immune and mechanical loading on chondrocytes in the development of knee rheumatoid osteoarthritis.

Osteopontin: A Bone-Derived Protein Involved in Rheumatoid Arthritis and Osteoarthritis Immunopathology

Osteopontin (OPN) is a bone-derived phosphoglycoprotein related to physiological and pathological mechanisms that nowadays has gained relevance due to its role in the immune system response to chronic degenerative diseases, including rheumatoid arthritis (RA) and osteoarthritis (OA). OPN is an extracellular matrix (ECM) glycoprotein that plays a critical role in bone remodeling. Therefore, it is an effector molecule that promotes joint and cartilage destruction observed in clinical studies, in vitro assays, and animal models of RA and OA. Since OPN undergoes multiple modifications, including posttranslational changes, proteolytic cleavage, and binding to a wide range of receptors, the mechanisms by which it produces its effects, in some cases, remain unclear. Although there is strong evidence that OPN contributes significantly to the immunopathology of RA and OA when considering it as a common denominator molecule, some experimental trial results argue for its protective role in rheumatic diseases. Elucidating in detail OPN involvement in bone and cartilage degeneration is of interest to the field of rheumatology. This review aims to provide evidence of the OPN’s multifaceted role in promoting joint and cartilage destruction and propose it as a common denominator of AR and OA immunopathology.

Dehydrocorydaline Accelerates Cell Proliferation and Extracellular Matrix Synthesis of TNFα-Treated Human Chondrocytes by Targeting Cox2 through JAK1-STAT3 Signaling Pathway

Osteoarthritis (OA) causes severe degeneration of the meniscus and cartilage layer in the knee and endangers joint integrity and function. In this study, we utilized tumor necrosis factor α (TNFα) to establish in vitro OA models and analyzed the effects of dehydrocorydaline (DHC) on cell proliferation and extracellular matrix (ECM) synthesis in human chondrocytes with TNFα treatment. We found that TNFα treatment significantly reduced cell proliferation and mRNA and protein expression levels of aggrecan and type II collagen, but caused an increase in mRNA and protein expression levels of type I collagen, matrix metalloproteinase 1/13 (MMP1/13), and prostaglandin-endoperoxide synthase 2 (PTGS2, also known as Cox2) in human chondrocytes. DHC significantly promoted the cell activity of normal human chondrocytes without showing cytotoxity. Moreover, 10 and 20 μM DHC clearly restored cell proliferation, inhibited mRNA and protein expression levels of type I collagen, MMP 1/13, and Cox2, and further increased those of aggrecan and type II collagen in the TNFα-treated human chondrocytes. RNA transcriptome sequencing indicated that DHC could improve TNFα-induced metabolic abnormalities and inflammation reactions and inhibit the expression of TNFα-induced inflammatory factors. Furthermore, we found that the JAK1-STAT3 signaling pathway was confirmed to be involved in the regulatory effects of DHC on cell proliferation and ECM metabolism of the TNFα-treated human chondrocytes. Lastly, to explore the effects of DHC in vivo, we established an anterior cruciate ligament transection (ACLT)-stimulated rat OA model and found that DHC administration significantly attenuated OA development, inhibited the enzymatic hydrolysis of ECM, and reduced phosphorylated JAK1 and STAT3 protein expression in vivo after ACLT for 6 weeks. These results suggest that DHC can effectively relieve OA progression, and it has a potential to be utilized for the clinical prevention and therapy of OA as a natural small molecular drug.

Crosstalk Among circRNA/lncRNA, miRNA, and mRNA in Osteoarthritis

Osteoarthritis (OA) is a joint disease that is pervasive in life, and the incidence and mortality of OA are increasing, causing many adverse effects on people's life. Therefore, it is very vital to identify new biomarkers and therapeutic targets in the clinical diagnosis and treatment of OA. ncRNA is a nonprotein-coding RNA that does not translate into proteins but participates in protein translation. At the RNA level, it can perform biological functions. Many studies have found that miRNA, lncRNA, and circRNA are closely related to the course of OA and play important regulatory roles in transcription, post-transcription, and post-translation, which can be used as biological targets for the prevention, diagnosis, and treatment of OA. In this review, we summarized and described the various roles of different types of miRNA, lncRNA, and circRNA in OA, the roles of different lncRNA/circRNA-miRNA-mRNA axis in OA, and the possible prospects of these ncRNAs in clinical application.

The Involvement of lncRNA HOTAIR/miR-130a-3p Axis in the Regulation of Voluntary Exercise on Cognition and Inflammation of Alzheimer's Disease

BACKGROUND

Alzheimer's disease (AD) is an age-related neurodegenerative disease and exercises might mitigate the progression of AD. This investigation aimed to manifest the potential mechanism of exercises in AD.

METHODS

Morris water maze (MWM) test was conducted to evaluate the cognitive function in APP/PS1 mice. Quantitative real-time PCR was performed to detect the expression of HOTAIR and miR-130a-3p. The enzyme-linked immunosorbent assay was applied to appraise the concentration of IL-1β, IL-6, and TNF-α. A luciferase report experiment was implemented to substantiate the relationship between miR-130a-3p and HOTAIR.

RESULTS

Exercises contributed to the elevated expression of HOTAIR. The findings of MWM implied HOTAIR inhibited the impacts of voluntary exercises on escape latency, distance moved, percentage of time spent in the target quadrant, platform crossing times, and inflammation. MiR-130a-3p mediated the function of HOTAIR on cognitive ability and inflammation.

CONCLUSION

HOTAIR participated in the regulation of exercises on AD by sponging miR-130a-3p.

Silencing Aurora-kinase-A (AURKA) reinforced the sensitivity of diffuse large B-cell lymphoma cells to cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) via suppressing β-Catenin and RAS-extracellular signal-regulated protein kinase (ERK1/2) pathway

The therapeutic effects of standard cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) therapy for prevalent lymphoma diffuse large B-cell lymphoma (DLBC, DLBCL) still require improvement. Cancer-related aurora-kinase-A (AURKA) may work as a target for DLBCL treatment and its effect on CHOP therapy was investigated in the present study. The Gene Expression Profiling Interactive Analysis 2 was applied to analyze AURKA expression in DLBC tumor tissues and normal lymphoid tissues. The DLBCL tissues and normal lymphoid tissues were obtained from the DLBCL patients and healthy volunteers. Clinic data of patients were recorded, and AURKA expression in tissues and cells was detected and analyzed using quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry. After AURKA in DLBCL cells was silenced or overexpressed and treated with CHOP, viability and apoptosis were detected by Cell Counting Kit-8 (CCK-8) assay and flow cytometry. Expressions of AURKA, β-Catenin, phosphorylated (p)-β-Catenin, extracellular signal-regulated protein kinase (ERK1/2), p-ERK1/2 and RAS were detected using qRT-PCR and Western blot. AURKA was highly expressed in DLBCL tissues and cells. Silencing AURKA inhibited AURKA expression and viability, but promoted apoptosis of DLBCL cells. CHOP had no obvious effects on AURKA expression while reducing viability and promoting apoptosis of DLBCL cells. Silencing AURKA enhanced the effects of CHOP on cell apoptosis of DLBCL cells by inhibiting the expressions of RAS and β-Catenin as well as the ratio of p-ERK1/2/ERK1/2 and promoting the ratio of p-β-Catenin/β-Catenin. Silencing AURKA reinforced the therapeutic effects of CHOP on reducing viability and promoting apoptosis of DLBCL cell via repressing β-Catenin and RAS-ERK1/2 pathway.

There and Back Again: Hox Clusters Use Both DNA Strands

Bilaterian animals operate the clusters of Hox genes through a rich repertoire of diverse mechanisms. In this review, we will summarize and analyze the accumulated data concerning long non-coding RNAs (lncRNAs) that are transcribed from sense (coding) DNA strands of Hox clusters. It was shown that antisense regulatory RNAs control the work of Hox genes in cis and trans, participate in the establishment and maintenance of the epigenetic code of Hox loci, and can even serve as a source of regulatory peptides that switch cellular energetic metabolism. Moreover, these molecules can be considered as a force that consolidates the cluster into a single whole. We will discuss the examples of antisense transcription of Hox genes in well-studied systems (cell cultures, morphogenesis of vertebrates) and bear upon some interesting examples of antisense Hox RNAs in non-model Protostomia.