Actin binding LIM 1 (abLIM1) negatively controls osteoclastogenesis by regulating cell migration and fusion

Comprehensive analysis of abnormal methylation modification differential expression mRNAs between low-grade and high-grade intervertebral disc degeneration and its correlation with immune cells

BACKGROUND

Intervertebral disc degeneration (IDD) is an important cause of low back pain. The aim of this study is to identify the potential molecular mechanism of abnormal methylation-modified DNA in the progression of IDD, hoping to contribute to the diagnosis and management of IDD.

METHODS

Low-grade IDD (grade I-II) and high-grade IDD (grade III-V) data were downloaded from GSE70362 and GSE129789 datasets. The abnormally methylated modified differentially expressed mRNAs (DEmRNAs) were identified by differential expression analysis (screening criteria were p < .05 and |logFC| > 1) and differential methylation analysis (screening criteria were p < .05 and |δβ| > 0.1). The classification models were constructed, and the receiver operating characteristic analysis was also carried out. In addition, functional enrichment analysis and immune correlation analysis were performed and the miRNAs targeted for the abnormally methylated DEmRNAs were predicted. Finally, expression validation was performed using real-time PCR.

RESULTS

Compared with low-grade IDD, seven abnormal methylation-modified DEmRNAs (AOX1, IBSP, QDPR, ABLIM1, CRISPLD2, ACTC1 and EMILIN1) were identified in high-grade IDD, and the classification models of random forests (RF) and support vector machine (SVM) were constructed. Moreover, seven abnormal methylation-modified DEmRNAs and classification models have high diagnostic accuracy (area under the curve [AUC] > 0.8). We also found that AUC values of single abnormal methylation-modified DEmRNA were all lower than those of RF and SVM classification models. Pearson correlation analysis found that macrophages M2 and EMILIN1 had significant negative correlation, while macrophages M2 and IBSP had significant positive correlation. In addition, four targeted relationship pairs (hsa-miR-4728-5p-QDPR, hsa-miR-4533-ABLIM1, hsa-miR-4728-5p-ABLIM1 and hsa-miR-4534-CRISPLD2) and multiple signalling pathways (for example, PI3K-AKT signalling pathway, osteoclast differentiation and calcium signalling pathway) were also identified that may be involved in the progression of IDD.

CONCLUSION

The identification of abnormal methylation-modified DEmRNAs and the construction of classification models in this study were helpful for the diagnosis and management of IDD progression.

Actin-Binding LIM 1 (ABLIM1) Inhibits Glioblastoma Progression and Serves as a Novel Prognostic Biomarker

Background

Glioma is the most prevalent malignant brain tumor in adult humans, and glioblastoma (GBM) is the most malignant type. The actin-binding LIM 1 (ABLIM1) protein can modulate actin polymerization, which is essential for the cell proliferation and migration. We aim to investigate ABLIM1 expression, function, and clinical significance in GBM.

Methods

The ABLIM1 mRNA level was extracted from the TCGA and GTEx online databases. The ABLIM1 protein expression level was explored using immunohistochemistry staining in a GBM cohort enrolled in our hospital (n = 104). The patient survival and prognostic factors were determined using the Kaplan-Meier method and multivariate Cox hazard proportional analysis, respectively. Two human GBM cell lines, U87 and U251 cells, were utilized for ABLIM1 overexpression and cell proliferation analyses. A subcutaneous xenograft model was generated using nude mice to validate the tumor-related effect of ABLIM1 in vivo.

Results

ABLIM1 exhibited a significantly lower mRNA level in GBM than in other glioma or normal brain tissues. Higher ABLIM1 protein level was correlated with smaller GBM tumor size and better cancer-specific survival (CSS). Multivariate analysis identified ABLIM1 as a novel independent prognostic factor for GBM prognosis. ABLIM1 overexpression significantly inhibits U87 and U251 cell proliferation and colony formation. Consistently, ABLIM1 exerted tumor-suppressing functions in mice models.

Conclusion

ABLIM1 plays antitumor roles in GBM progression and could be served as a novel biomarker to help predict GBM prognosis.

Coronin1C Is a GDP-Specific Rab44 Effector That Controls Osteoclast Formation by Regulating Cell Motility in Macrophages

Osteoclasts are multinucleated bone-resorbing cells that are formed by the fusion of macrophages. Recently, we identified Rab44, a large Rab GTPase, as an upregulated gene during osteoclast differentiation that negatively regulates osteoclast differentiation. However, the molecular mechanisms by which Rab44 negatively regulates osteoclast differentiation remain unknown. Here, we found that the GDP form of Rab44 interacted with the actin-binding protein, Coronin1C, in murine macrophages. Immunoprecipitation experiments revealed that the interaction of Rab44 and Coronin1C occurred in wild-type and a dominant-negative (DN) mutant of Rab44, but not in a constitutively active (CA) mutant of Rab44. Consistent with these findings, the expression of the CA mutant inhibited osteoclast differentiation, whereas that of the DN mutant enhanced this differentiation. Using a phase-contrast microscope, Coronin1C-knockdown osteoclasts apparently impaired multinuclear formation. Moreover, Coronin1C knockdown impaired the migration and chemotaxis of RAW-D macrophages. An in vivo experimental system demonstrated that Coronin1C knockdown suppresses osteoclastogenesis. Therefore, the decreased cell formation and fusion of Coronin1C-depleted osteoclasts might be due to the decreased migration of Coronin1C-knockdown macrophages. These results indicate that Coronin1C is a GDP-specific Rab44 effector that controls osteoclast formation by regulating cell motility in macrophages.

A Second-Generation Nanoluc-IL27 Fusion Cytokine for Targeted-Gene-Therapy Applications

An emerging approach in treating skeletal malignancies utilizes osteoimmunology to investigate new multifunctional immune-stimulatory agents that can simultaneously combat tumor growth and promote bone repair. We have hypothesized that cytokine Interleukin-27 (IL-27) is an excellent candidate biologic to help rebalance the prostate tumor cells and bone cell environment. In this work, we examined the proof of principle for a short, secreted luciferase (Nanoluc or Nluc) fusion with IL-27 to produce a novel cytokine-based biologic (Nluc-27), whereby we examined its efficacy in vitro in reducing prostate tumor growth and rebalancing bone cell proliferation and differentiation. This work demonstrates the targeting and anti-tumor efficacy of the Nluc-27 fusion cytokine in cancer and bone cell models. The fusion cytokine is detectable in conditioned media, and bioactive in different cell systems. This novel Nluc-27 cytokine will allow flexible incorporation of other targeting domains and may serve as flexible tool to augment IL-27′s bioactivity and reengineer its efficacy against prostate tumor or bone cells, and may prove applicable to several other cell types for targeted gene therapy applications.

Heterogeneity and Actin Cytoskeleton in Osteoclast and Macrophage Multinucleation

Osteoclast signatures are determined by two transcriptional programs, the lineage-determining transcription pathway and the receptor activator of nuclear factor kappa-B ligand (RANKL)-dependent differentiation pathways. During differentiation, mononuclear precursors become multinucleated by cell fusion. Recently, live-cell imaging has revealed a high level of heterogeneity in osteoclast multinucleation. This heterogeneity includes the difference in the differentiation states and the mobility of the fusion precursors, as well as the mode of fusion among the fusion precursors with different numbers of nuclei. In particular, fusion partners often form morphologically distinct actin-based linkages that allow two cells to exchange lipids and proteins before membrane fusion. However, the origin of this heterogeneity remains elusive. On the other hand, osteoclast multinucleation is sensitive to the environmental cues. Such cues promote the reorganization of the actin cytoskeleton, especially the formation and transformation of the podosome, an actin-rich punctate adhesion. This review covers the heterogeneity of osteoclast multinucleation at the pre-fusion stage with reference to the environment-dependent signaling pathway responsible for reorganizing the actin cytoskeleton. Furthermore, we compare osteoclast multinucleation with macrophage fusion, which results in multinucleated giant macrophages.

Coordinated Circulating T Follicular Helper and Activated B Cell Responses Underlie the Onset of Antibody-Mediated Rejection in Kidney Transplantation

BACKGROUND

Although antibody-mediated rejection (ABMR) has been long recognized as a leading cause of allograft failure after kidney transplantation, the cellular and molecular processes underlying the induction of deleterious donor-specific antibody (DSA) responses remain poorly understood.

METHODS

Using high-dimensional flow cytometry, in vitro assays, and RNA sequencing, we concomitantly investigated the role of T follicular helper (T_FH) cells and B cells during ABMR in 105 kidney transplant recipients.

RESULTS

There were 54 patients without DSAs; of those with DSAs, ABMR emerged in 20 patients, but not in 31 patients. We identified proliferating populations of circulating T_FH cells and activated B cells emerging in blood of patients undergoing ABMR. Although these circulating T_FH cells comprised heterogeneous phenotypes, they were dominated by activated (ICOS⁺PD-1⁺) and early memory precursor (CCR7⁺CD127⁺) subsets, and were enriched for the transcription factors IRF4 and c-Maf. These circulating T_FH cells produced large amounts of IL-21 upon stimulation with donor antigen and induced B cells to differentiate into antibody-secreting cells that produced DSAs. Combined analysis of the matched circulating T_FH cell and activated B cell RNA-sequencing profiles identified highly coordinated transcriptional programs in circulating T_FH cells and B cells among patients with ABMR, which markedly differed from those of patients who did not develop DSAs or ABMR. The timing of expansion of the distinctive circulating T_FH cells and activated B cells paralleled emergence of DSAs in blood, and their magnitude was predictive of IgG3 DSA generation, more severe allograft injury, and higher rate of allograft loss.

CONCLUSIONS

Patients undergoing ABMR may benefit from monitoring and therapeutic targeting of T_FH cell-B cell interactions.

LncRNA ZNF667-AS1 Promotes ABLIM1 Expression by Adsorbing micro RNA-1290 to Suppress Nasopharyngeal Carcinoma Cell Progression

Background

Recently, long non-coding RNAs (lncRNAs) have been elucidated to play essential roles in cancers, and the recognition of lncRNA expression patterns in nasopharyngeal carcinoma (NPC) may be helpful for indicating novel mechanisms underlying NPC carcinogenesis. Herein, we conducted this study to probe into the function of lncRNA ZNF667-AS1 in NPC progression with the involvement of microRNA-1290 (miR-1290) and actin-binding LIM protein 1 (ABLIM1).

Materials and Methods

In silico analysis screened differentially expressed genes and miRNAs in NPC and predicted potential mechanisms. ZNF667-AS1 expression was detected in NPC tissues and cells. The gain-and-loss function assays were performed to explore the effects of lncRNA ZNF667-AS1 and miR-1290 in NPC cell biological behaviors. In vivo experiments were further conducted to confirm the in vitro results.

Results

In silico analysis predicted that ZNF667-AS1 was diminished in NPC, which may downregulate ABLIM1 through sponging miR-1290. ZNF667-AS1 was poorly expressed in NPC tissues and cells, and overexpression of ZNF667-AS1 inhibited growth of NPC cells. ZNF667-AS1 competitively bound with miR-1290, thereby upregulating ABLIM1. miR-1290 resulted in the promotion of NPC cell progression by suppressing ABLIM1. Overexpression of ZNF667-AS1 or suppression of miR-1290 inhibited tumorigenicity of NPC cells in vivo.

Conclusion

This study highlights that lncRNA ZNF667-AS1 promotes ABLIM1 expression by sponging miR-1290 to suppress NPC cell progression.