Targeted Apoptosis of Senescent Cells Restores Tissue Homeostasis in Response to Chemotoxicity and Aging

The accumulation of irreparable cellular damage restricts healthspan after acute stress or natural aging. Senescent cells are thought to impair tissue function, and their genetic clearance can delay features of aging. Identifying how senescent cells avoid apoptosis allows for the prospective design of anti-senescence compounds to address whether homeostasis can also be restored. Here, we identify FOXO4 as a pivot in senescent cell viability. We designed a FOXO4 peptide that perturbs the FOXO4 interaction with p53. In senescent cells, this selectively causes p53 nuclear exclusion and cell-intrinsic apoptosis. Under conditions where it was well tolerated in vivo, this FOXO4 peptide neutralized doxorubicin-induced chemotoxicity. Moreover, it restored fitness, fur density, and renal function in both fast aging Xpd^TTD/TTD and naturally aged mice. Thus, therapeutic targeting of senescent cells is feasible under conditions where loss of health has already occurred, and in doing so tissue homeostasis can effectively be restored.

GRSF1-mediated MIR-G-1 promotes malignant behavior and nuclear autophagy by directly upregulating TMED5 and LMNB1 in cervical cancer cells

Emerging evidence has revealed that miRNAs could upregulate the expression levels of target genes. However, the molecular mechanism underlying upregulation of targets mediated by miRNAs remains unclear. In this study, we found a novel miRNA named MIR-G-1 by GRSF1-RNA immunoprecipitation (RIP)-deep sequencing, which could directly target and upregulate LMNB1 and TMED5 in a GRSF1-dependent manner in cervical cancer cells. In addition, upregulated MIR-G-1 in cervical cancer promoted a malignant phenotype in vitro and in vivo. TMED5 could interact with WNT7B and thus activated the canonical WNT-CTNNB1/β-catenin signaling pathway. MIR-G-1 mediated the activation of this pathway. Furthermore, MIR-G-1 promoted serum starvation-induced nuclear macroautophagy/autophagy, and accelerated taxol (TAX)-induced DNA-damage repair in cervical cancer cells. Collectively, these findings may provide a new insight into the upregulation mechanism and nuclear autophagy mediated by miRNAs and provide a potential biomarker for cervical cancer. Abbreviations: 3'UTR: 3' untranslated region; EMSA: electrophoretic mobility shift assay; EMT: epithelial-mesenchymal transition; GRSF1: G-rich RNA sequence binding factor 1; IF: immunofluorescence; IP: immunoprecipitation; IHC: immunohistochemistry; lnc: long noncoding; miRNA:microRNA; TAX: taxol; TMED5: transmembrane p24 trafficking protein 5.

Suppression of p16 alleviates the senescence-associated secretory phenotype

Oncogene-induced senescence (OIS) is characterized by increased expression of the cell cycle inhibitor p16, leading to a hallmark cell cycle arrest. Suppression of p16 in this context drives proliferation, senescence bypass, and contributes to tumorigenesis. OIS cells are also characterized by the expression and secretion of a widely variable group of factors collectively termed the senescence-associated secretory phenotype (SASP). The SASP can be both beneficial and detrimental and affects the microenvironment in a highly context-dependent manner. The relationship between p16 suppression and the SASP remains unclear. Here, we show that knockdown of p16 decreases expression of the SASP factors and pro-inflammatory cytokines IL6 and CXCL8 in multiple models, including OIS and DNA damage-induced senescence. Notably, this is uncoupled from the senescence-associated cell cycle arrest. Moreover, low p16 expression in both cancer cell lines and patient samples correspond to decreased SASP gene expression, suggesting this is a universal effect of loss of p16 expression. Together, our data suggest that p16 regulates SASP gene expression, which has implications for understanding how p16 modulates both the senescent and tumor microenvironment.

Heterozygous lamin B1 and lamin B2 variants cause primary microcephaly and define a novel laminopathy

PURPOSE

Lamins are the major component of nuclear lamina, maintaining structural integrity of the nucleus. Lamin A/C variants are well established to cause a spectrum of disorders ranging from myopathies to progeria, termed laminopathies. Phenotypes resulting from variants in LMNB1 and LMNB2 have been much less clearly defined.

METHODS

We investigated exome and genome sequencing from the Deciphering Developmental Disorders Study and the 100,000 Genomes Project to identify novel microcephaly genes.

RESULTS

Starting from a cohort of patients with extreme microcephaly, 13 individuals with heterozygous variants in the two human B-type lamins were identified. Recurrent variants were established to be de novo in nine cases and shown to affect highly conserved residues within the lamin ɑ-helical rod domain, likely disrupting interactions required for higher-order assembly of lamin filaments.

CONCLUSION

We identify dominant pathogenic variants in LMNB1 and LMNB2 as a genetic cause of primary microcephaly, implicating a major structural component of the nuclear envelope in its etiology and defining a new form of laminopathy. The distinct nature of this lamin B-associated phenotype highlights the strikingly different developmental requirements for lamin paralogs and suggests a novel mechanism for primary microcephaly warranting future investigation.

De Novo Variants in LMNB1 Cause Pronounced Syndromic Microcephaly and Disruption of Nuclear Envelope Integrity

Lamin B1 plays an important role in the nuclear envelope stability, the regulation of gene expression, and neural development. Duplication of LMNB1, or missense mutations increasing LMNB1 expression, are associated with autosomal-dominant leukodystrophy. On the basis of its role in neurogenesis, it has been postulated that LMNB1 variants could cause microcephaly. Here, we confirm this hypothesis with the identification of de novo mutations in LMNB1 in seven individuals with pronounced primary microcephaly (ranging from -3.6 to -12 SD) associated with relative short stature and variable degree of intellectual disability and neurological features as the core symptoms. Simplified gyral pattern of the cortex and abnormal corpus callosum were noted on MRI of three individuals, and these individuals also presented with a more severe phenotype. Functional analysis of the three missense mutations showed impaired formation of the LMNB1 nuclear lamina. The two variants located within the head group of LMNB1 result in a decrease in the nuclear localization of the protein and an increase in misshapen nuclei. We further demonstrate that another mutation, located in the coil region, leads to increased frequency of condensed nuclei and lower steady-state levels of lamin B1 in proband lymphoblasts. Our findings collectively indicate that de novo mutations in LMNB1 result in a dominant and damaging effect on nuclear envelope formation that correlates with microcephaly in humans. This adds LMNB1 to the growing list of genes implicated in severe autosomal-dominant microcephaly and broadens the phenotypic spectrum of the laminopathies.

Allele-specific silencing as treatment for gene duplication disorders: proof-of-principle in autosomal dominant leukodystrophy

Allele-specific silencing by RNA interference (ASP-siRNA) holds promise as a therapeutic strategy for downregulating a single mutant allele with minimal suppression of the corresponding wild-type allele. This approach has been effectively used to target autosomal dominant mutations and single nucleotide polymorphisms linked with aberrantly expanded trinucleotide repeats. Here, we propose ASP-siRNA as a preferable choice to target duplicated disease genes, avoiding potentially harmful excessive downregulation. As a proof-of-concept, we studied autosomal dominant adult-onset demyelinating leukodystrophy (ADLD) due to lamin B1 (LMNB1) duplication, a hereditary, progressive and fatal disorder affecting myelin in the CNS. Using a reporter system, we screened the most efficient ASP-siRNAs preferentially targeting one of the alleles at rs1051644 (average minor allele frequency: 0.45) located in the 3' untranslated region of the gene. We identified four siRNAs with a high efficacy and allele-specificity, which were tested in ADLD patient-derived fibroblasts. Three of the small interfering RNAs were highly selective for the target allele and restored both LMNB1 mRNA and protein levels close to control levels. Furthermore, small interfering RNA treatment abrogates the ADLD-specific phenotypes in fibroblasts and in two disease-relevant cellular models: murine oligodendrocytes overexpressing human LMNB1, and neurons directly reprogrammed from patients' fibroblasts. In conclusion, we demonstrated that ASP-silencing by RNA interference is a suitable and promising therapeutic option for ADLD. Moreover, our results have a broad translational value extending to several pathological conditions linked to gene-gain in copy number variations.

METTL3-mediated N6-methyladenosine modification stimulates mitochondrial damage and ferroptosis of kidney tubular epithelial cells following acute kidney injury by modulating the stabilization of MDM2-p53-LMNB1 axis

N6-methyladenosine (m6A) and MELLT3 assume a role in the development of acute kidney injury (AKI). However, their mechanism in AKI remains under-explored. On this basis, this study explored the mechanism of MELLT3 in mitochondrial damage and ferroptosis of kidney tubular epithelial cells after AKI. HK-2 cells were induced by lipopolysaccharide (LPS) to simulate AKI, followed by gain and loss of function of genes, detection of mitochondrial damage and ferroptosis indicators, and analysis of gene interactions. An AKI mouse model was developed using the cecal ligation and puncture (CLP) method to investigate the effect of METTL3 knockdown on kidney injury. MDM2 and LMNB1 were upregulated and p53 was downregulated in LPS-treated HK-2 cells. Mechanistically, the E3 ubiquitin ligase MDM2 increased p53 ubiquitination to activate LMNB1. METTL3 knockdown decreased m6A methylation of MDM2, thus diminishing YTHDF1-mediated MDM2 mRNA stability and translation in LPS-treated HK-2 cells. Knockdown of LMNB1, MDM2, or METTL3 reduced NO, MDA, iron ion, and ROS levels as well as mitochondrial damage and raised SOD, GSH, XCT, GPX4, FPN1, and TFR1 levels in LPS-treated HK-2 cells. The in vivo results showed that METTL3 knockdown reduced renal injury and ferroptosis in CLP mice. METTL3 knockdown prevents mitochondrial damage and ferroptosis of kidney tubular epithelial cells after AKI via the MDM2-p53-LMNB1 axis.

Silencing LMNB1 Contributes to the Suppression of Lung Adenocarcinoma Development

Purpose

Lung cancer has been recognized as the most fatal malignant tumor with the highest morbidity and mortality in recent years.

Materials and Methods

In this study, we found that LMNB1, which is an important component protein of the nuclear skeleton, was significantly upregulated in lung adenocarcinoma (LUAD) and correlated with the pathological stage as well as lymphatic metastasis.

Results

In vitro loss-of-function study utilizing LMNB1 knockdown LUAD cell lines demonstrated that depletion of LMNB1 inhibited development of LUAD through regulating cell proliferation, cell apoptosis, cell cycle and cell motility. Decreased tumorigenesis of LMNB1 knockdown LUAD cells was proved in mice xenograft models. Moreover, the mechanism by which LMNB1 promotes LUAD was explored through the expression evaluation of apoptosis-related proteins and cancer-related signaling pathways.

Conclusion

In conclusion, our study identified LMNB1 as a tumor promotor and a potential therapeutic target in LUAD.

Pan-cancer analysis identifies LMNB1 as a target to redress Th1/Th2 imbalance and enhance PARP inhibitor response in human cancers

Background

Emerging evidence suggests that LMNB1 is involved in the development of multiple cancer types. However, there is no study reporting the potential role of LMNB1 in a systematic pan-cancer manner.

Methods

The gene expression level and potential oncogenic roles of LMNB1 in The Cancer Genome Atlas (TCGA) database were analyzed with Tumor Immune Estimation Resource version 2 (TIMER2.0), Gene Expression Profiling Interactive Analysis version 2 (GEPIA2), UALCAN and Sangerbox tools. Pathway enrichment analysis was carried out to explore the possible mechanism of LMNB1 on tumorigenesis and tumor progression. The therapeutic effects of LMNB1 knockdown combined with PARP inhibition on human cancers were further investigated in vitro.

Results

LMNB1 upregulation is generally observed in the tumor tissues of most TCGA cancer types, and is verified in kidney renal clear cell carcinoma using clinical specimens of our institute. High level of LMNB1 expression usually predicts poor overall survival and disease free survival for patients with tumors. Mechanically, LMNB1 level is positively correlated with CD4+ Th2 cell infiltration and DNA homologous recombination repair gene expression. In vitro experiments reveal that targeting LMNB1 has a synergistic effect on prostate cancer with PARP inhibitor treatment.

Conclusions

LMNB1 is a biomarker of CD4+ Th2 cell infiltration and DNA homologous recombination repair in human cancers. Blockage of LMNB1 combined with PARP inhibitor treatment could be a promising therapeutic strategy for patients with cancers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02467-4.

Knockdown of LMNB1 Inhibits the Proliferation of Lung Adenocarcinoma Cells by Inducing DNA Damage and Cell Senescence

Background

Lung cancer has considerably high mortality and morbidity rate. Lung adenocarcinoma (LUAD) tissues highly express lamin B1 (LMNB1), compared with normal tissues. In this study, we knocked down LMNB1 in LUAD cells A549 and NCI-1299 to explore the effect of its inhibition on the proliferation of cells and the potential mechanism.

Methods

Using bioinformatics methods, we analyzed the specificity of LMNB1 mRNA expression level in LUAD and its effect on prognosis from TCGA data. SiRNAs were used to knock down LMNB1 in the A549 cell line, and the knockdown effect was identified by western blotting and qRT-PCR. Through CCK8 cell proliferation assay, wound healing assay, TRAP, cloning formation Assay, DNase I-TUNEL assay, ATAC-seq, immunofluorescence, FISH, in vivo mouse xenograft studies, etc, we evaluated the influence and mechanism of LMNB1 on LUAD cell line proliferation in vitro and in vivo.

Results

According to bioinformatics analysis, LMNB1 is substantially abundant in LUAD tissues and is associated with tumor stage and patient survival (P < 0.05). After silencing LMNB1, the rate of cell growth, wound healing, the number of transwells, and the number of cell colonies all decreased significantly (P < 0.01). With the decreased LMNB1 expression, H3K9me3 protein expression decreases, chromosome accessibility increases, P53, P21, P16 and γ-H2AX protein expression increases, and the number of senescence staining positive cells increases. At the same time, in vivo mouse xenograft experiments showed that the tumor volume of the LMNB1-silenced group was significantly reduced, compared to that of the control group (P < 0.01), and the proliferation biomarker Ki-67 level (P < 0.01) was considerably reduced.

Conclusions

Overexpression of LMNB1 in LUAD cells is significant, which has excellent potential to be an indicator for evaluating the clinical prognosis of LUAD patients and a target for precise treatment.

Lamin B1 is a potential therapeutic target and prognostic biomarker for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is an aggressive malignancy. Previous studies have found that lamin B1 (LMNB1) contributes to the development of human cancers. However, the biological functions and prognostic values of LMNB1 in HCC have not been adequately elucidated. In our present research, the expression pattern of LMNB1 was analyzed. The prognostic values of LMNB1 were evaluated by Kaplan-Meier survival analysis and Cox proportional hazards regression analysis. The effects of LMNB1 on HCC progression were assessed by Cell Counting Kit-8 (CCK-8), colony formation, wound healing, Transwell and in vivo xenograft assays. The mechanisms of LMNB1 in HCC progression were elucidated by gene set enrichment analysis (GSEA) and loss-of-function assays. Besides, a nomogram for predicting overall survival (OS) was constructed. The results demonstrated that LMNB1 was overexpressed in HCC and that increased LMNB1 expression predicted a dismal prognosis. Further experiments showed that LMNB1 facilitated cell proliferation and metastasis in HCC. Functional enrichment analysis revealed that LMNB1 modulated metastasis-associated biological functions such as focal adhesion, extracellular matrix, cell junctions and cell adhesion. Mechanistically, we revealed that LMNB1 promoted HCC progression by regulating the phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) pathways. Moreover, incorporating LMNB1, Ki67 and Barcelona Clinic Liver Cancer (BCLC) stage into a nomogram showed better predictive accuracy than the Tumor-Node-Metastasis (TNM) stage and BCLC stage. In conclusion, LMNB1 may serve as an effective therapeutic target as well as a reliable prognostic biomarker for HCC.

Rapid and high-purity differentiation of human medium spiny neurons reveals LMNB1 hypofunction and subtype necessity in modeling Huntington's disease

BACKGROUND

Different neural subtypes are selectively lost in diverse neurodegenerative diseases. Huntington's disease (HD) is an inherited neurodegenerative disease characterized by motor abnormalities that primarily affect the striatum. The Huntingtin (HTT) mutation involves an expanded CAG repeat, leading to insoluble polyQ, which renders GABA+ medium spiny neurons (MSN) more venerable to cell death. Human pluripotent stem cells (hPSCs) technology allows for the construction of disease-specific models, providing valuable cellular models for studying pathogenesis, drug screening, and high-throughput analysis.

METHODS

In this study, we established a method that allows for rapid and efficient generation of MSNs (> 90%) within 21 days from hPSC-derived neural progenitor cells, by introducing a specific combination of transcription factors.

RESULTS

We efficiently induced several neural subtypes, in parallel, based on the same cell source, and revealed that, compared to other neural subtypes, MSNs exhibited higher polyQ aggregation propensity and overexpression toxicity, more severe dysfunction in BDNF/TrkB signaling, greater susceptibility to BDNF withdrawal, and more severe disturbances in nucleocytoplasmic transport (NCT). We further found that the nuclear lamina protein LMNB1 was greatly reduced in HD neurons and mislocalized to the cytoplasm and axons. Knockdown of HTT or treatment with KPT335, an orally selective inhibitor of nuclear export (SINE), effectively attenuated the pathological phenotypes and alleviated neuronal death caused by BDNF withdrawal.

CONCLUSIONS

This study thus establishes an effective method for obtaining MSNs and underscores the necessity of using high-purity MSNs to study HD pathogenesis, especially the MSN-selective vulnerability.

Screening and identification of LMNB1 and DLGAP5, two key biomarkers in gliomas

Glioma is the most common primary cancer in the central nervous system. Despite advances in surgery, radiotherapy and chemotherapy over the past decades, the prognosis of glioblastoma patients remains poor. We aim to identify robust gene signatures to better understand the complex molecular mechanisms and to discover potential novel molecular biomarkers for glioma. By exploring GSE16011, GSE4290 and GSE50161 data in Gene Expression Omnibus (GEO) database, we screened out 380 differentially expressed genes between non-tumor and glioma tissues, and further selected 30 hub genes through the Molecular Complex Detection (MCODE) plug-in in Cytoscape. In addition, LMNB1 and DLGAP5 were selected for further analyses due to their high expression in gliomas and were verified by using our cohort. Our study confirmed that LMNB1 and DLGAP5 were up-regulated in gliomas, and patients with high expression of LMNB1 or DLGAP5 had poor survival rate. Furthermore, silence of LMNB1 and DLGAP5 inhibited the proliferation of glioma cells. Together, LMNB1 and DLGAP5 were two potentially novel molecular biomarkers for diagnosis and prognosis of glioma.

Combined treatment with Aronia berry extract and oligomeric proanthocyanidins exhibit a synergistic anticancer efficacy through LMNB1-AKT signaling pathways in colorectal cancer

Colorectal cancer (CRC) is one of the most prevalent and highly recurrent malignancies worldwide and currently ranks as the second leading cause of cancer-related deaths. The high degree of morbidity and mortality associated with CRC is primarily attributed to the limited effectiveness of current therapeutic approaches and the emergence of chemoresistance to standard treatment modalities. Recent research indicates that several natural products, including Aronia berry extracts (ABE) and oligomeric proanthocyanidins (OPCs), might offer a safe, cost-effective, and multitargeted adjunctive role to cancer treatment. Herein, we hypothesized a combined treatment with ABE and OPCs could synergistically modulate multiple oncogenic pathways in CRC, thereby enhancing their anticancer activity. We initially conducted a series of in vitro experiments to assess the synergistic anticancer effects of ABE and OPCs on CRC cell lines. We demonstrate that these two compounds exhibited a superior synergistic anticancer potential versus individual treatments in enhancing the ability to inhibit cell viability, suppress colony formation, and induce apoptosis (p < 0.05). Consistent with our in vitro findings, we validated this combinatorial anticancer effect in tumor-derived 3D organoids (PDOs; p < 0.01). Using genome-wide transcriptomic profiling, we identified that a specific gene, LMNB1, associated with the cell apoptosis pathway, was found to play a crucial role in exhibiting anticancer effects with these two products. Furthermore, the combined treatment of ABE and OPCs significantly impacted the expression of key proteins involved in apoptosis, including suppressed expression levels of LMNB1 in CRC cell lines (p < 0.05), which resulted in inhibiting downstream AKT phosphorylation. In conclusion, our study provides novel evidence of the synergistic anticancer effects of ABE and OPCs in CRC cells, partially mediated through the regulation of apoptosis and the oncogene LMNB1 within the AKT signaling pathway. These findings have the potential to better appreciate the anticancer potential of natural products in CRC and help improve treatment outcomes in this malignancy.

A high-content drug screening strategy to identify protein level modulators for genetic diseases: A proof-of-principle in autosomal dominant leukodystrophy

In genetic diseases, the most prevalent mechanism of pathogenicity is an altered expression of dosage-sensitive genes. Drugs that restore physiological levels of these genes should be effective in treating the associated conditions. We developed a screening strategy, based on a bicistronic dual-reporter vector, for identifying compounds that modulate protein levels, and used it in a pharmacological screening approach. To provide a proof-of-principle, we chose autosomal dominant leukodystrophy (ADLD), an ultra-rare adult-onset neurodegenerative disorder caused by lamin B1 (LMNB1) overexpression. We used a stable Chinese hamster ovary (CHO) cell line that simultaneously expresses an AcGFP reporter fused to LMNB1 and a Ds-Red normalizer. Using high-content imaging analysis, we screened a library of 717 biologically active compounds and approved drugs, and identified alvespimycin, an HSP90 inhibitor, as a positive hit. We confirmed that alvespimycin can reduce LMNB1 levels by 30%-80% in five different cell lines (fibroblasts, NIH3T3, CHO, COS-7, and rat primary glial cells). In ADLD fibroblasts, alvespimycin reduced cytoplasmic LMNB1 by about 50%. We propose this approach for effectively identifying potential drugs for treating genetic diseases associated with deletions/duplications and paving the way toward Phase II clinical trials.

LMNB1 deletion in ovarian cancer inhibits the proliferation and metastasis of tumor cells through PI3K/Akt pathway

Ovarian cancer (OC) is a common malignant tumor in gynecology. LMNB1 is an important component of the nuclear skeleton. The expression of LMNB1 in ovarian cancer is significantly higher than that in normal tissues, but its role in tumor still needs comprehensive investigation. In this study, we overexpressed and knocked down LMNB1 in ovarian cancer cells and explore the effect of LMNB1 on the cell proliferation, migration and the underlying mechanism. We analyzed the expression levels of LMNB1 in ovarian cancer and their clinical relevance by using bioinformatics methods, qRT-PCR, Western blot and immunohistochemistry. To state the effect and mechanism of LMNB1 on OC in vitro and in vivo, we performed mouse xenograft studies, CCK8, cloning formation, Edu incorporation, wound healing, transwell and flow cytometry assay in stable LMNB1 knockdown OC cells, following by RNA-seq. Overexpression of LMNB1 indicates the progression of OC. LMNB1 knockdown inhibited the proliferation and migration of OC cells by suppressing the FGF1-mediated PI3K-Akt signaling pathway. Our study shows LMNB1 as a novel prognostic factor and therapeutic target in OC.

Lamin B1: a novel biomarker in adult and pediatric adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a malignancy with a poor prognosis and high mortality rate. A high tumor mutational burden (TMB) has been found to be associated with poor prognosis in ACC. Thus, exploring ACC biomarkers based on TMB holds significant importance for patient risk stratification. In our research, we utilized weighted gene coexpression network analysis and an assay for transposase-accessible chromatin with high-throughput sequencing to identify genes associated with TMB. Through the comprehensive analysis of various public datasets, Lamin B1 (LMNB1) was identified as a biomarker associated with a high TMB and low chromatin accessibility. Immunohistochemical staining demonstrated high expression of LMNB1 in ACC compared to noncancerous tissues. Functional enrichment analyses revealed that the function of LMNB1 is associated with cell proliferation and division. Furthermore, cell assays suggested that LMNB1 promotes tumor proliferation and invasion. In addition, mutation analysis suggested that the high expression of LMNB1 is associated with TP53 mutations. Additionally, LMNB1 was highly expressed in the vast majority of solid tumors across cancers. In our immune analysis, we discovered that the high expression of LMNB1 might suppress the infiltration of CD8+ T cells in the ACC microenvironment. In summary, LMNB1 is a predictive factor for the poor prognosis of adult and pediatric ACC. Its high expression in ACC is positively associated with high TMB and lower chromatin accessibility, and it promotes ACC cell proliferation and invasion. Therefore, LMNB1 holds promise as a novel biomarker and potential therapeutic target for ACC.

LMNB1, a potential marker for early prostate cancer progression

Although prostate cancer (PC) is the most common cancer among men in the Western world, there are no good biomarkers that can reliably differentiate between potentially aggressive and indolent PC. This leads to overtreatment, even for patients who can be managed conservatively. Previous studies have suggested that nuclear lamin proteins-especially lamin B1 (LMNB1)-play important roles in PC progression. However, the results of these studies are inconsistent. Here, we transfected the LMNB1 gene into the telomerase reverse transcriptase-immortalized benign prostatic epithelial cell line, EP156T to generate a LMNB1-overexpressing EP156T (LMN-EP156T) cell line with increased cellular proliferation. However, LMN-EP156T cells could neither form colonies in soft agar, nor establish subcutaneous growth or metastasis in the xenograft NOD/SCID mouse model. In addition, immunohistochemical staining of LMNB1 in PC specimens from 143 patients showed a statistically significant trend of stronger LMNB1 staining with higher Gleason scores. A univariate analysis of the clinicopathological parameters of 85 patients with PC who underwent radical prostatectomy revealed that pathological stage, resection margin, and extracapsular extension were significant predictors for biochemical recurrence (BCR). However, LMNB1 staining showed only a non-significant trend of association with BCR (high vs. low staining: hazard ratio (HR), 1.83; 95% confidence interval (CI), 0.98-3.41; P = 0.059). In multivariate analysis, only pathological stage was a significant independent predictor of BCR (pT3 vs. pT2: HR, 2.29; 95% CI, 1.18-4.43; P = 0.014). In summary, LMNB1 may play a role in the early steps of PC progression, and additional molecular alterations may be needed to confer full malignancy potential to initiated cells.

Activation of α7 nicotinic acetylcholine receptor promotes HIV-1 transcription

Alpha7 nicotinic acetylcholine receptor (α7 nAChR), a hub of the cholinergic anti-inflammatory pathway (CAP), is required for the treatment of inflammatory diseases. HIV-1 infection can upregulate the expression of α7 nAChR in T lymphocytes and affect the role of CAP. However, whether α7 nAChR regulates HIV-1 infection in CD4+ T cells is unclear. In this study, we first found that activation of α7 nAChR by GTS-21 (an α7 nAChR agonist) can promote the transcription of HIV-1 proviral DNA. Then, through transcriptome sequencing analysis, we found that p38 MAPK signaling was enriched in GTS-21 treated HIV-latent T cells. Mechanistically, activation of α7 nAChR could increase reactive oxygen species (ROS), reduce DUSP1 and DUSP6, and consequently enhance the phosphorylation of p38 MAPK. By co-immunoprecipitation and liquid chromatography tandem mass spectrometry, we found that p-p38 MAPK interacted with Lamin B1 (LMNB1). Activation of α7 nAChR increased the binding between p-p38 MAPK and LMNB1. We confirmed that knockdown of MAPK14 significantly downregulated NFATC4, a key activator of HIV-1 transcription. Taken together, activation of the α7 nAChR could trigger ROS/p-p38 MAPK/LMNB1/NFATC4 signaling pathway enhancing HIV-1 transcription. We have revealed an unrecognized mechanism of α7 nAChR-mediated neuroimmune regulation of HIV infection.

Impact of Nuclear Peripheral Chromatin Lamin LMNB1 Gene in the Proliferation and Migration of Glioma Cells

The goal of this study is to explore the role of the LMNB1 gene in glioma. A cohort of 160 patients who underwent glioma surgery were randomly selected of this study. The LMNB1 expression was assessed employing immunohistochemical and real-time quantitative polymerase chain reaction methods. Initially, RNA interference technology was applied to suppress gene expression, followed by the evaluation of tumor cell proliferation, apoptosis, cell cycle dynamics, and migration. The underlying molecular mechanisms of LMNB1 function were examined by a human phospho-kinase array and immunoblotting. And we established the xenograft models to determine the effect of tumor growth as well as the degree of invasion in shLMNB1 mice. Elevated LMNB1 expression correlated with unfavorable overall survival and disease-free survival. A substantial inhibition in cell growth was observed subsequent to LMNB1 knockdown in SHG-44 and U251 glioma cells. SHG-44-shLMNB1 cells exhibited a reduction in the S phase population, along with an increase in cells in G1 and G2 phases. Similarly, shLMNB1 U251 cells showed fewer cells in the S phase and an elevation in cells in G1 phase. Notably, increased apoptosis was observed in U251-shLMNB1 cells and SHG-44-shLMNB1 cells. Wound healing and Transwell migration assays demonstrated a significant decrease in the migration rate of both SHG-44-shLMNB1 and U251-shLMNB1 cells. The phosphorylation levels of Akt1/2/3, as well as the expressions of PI3K, AKT, and p-AKT proteins, were reduced in the shLMNB1 group. Downregulation of LMNB1 repressed tumor progress in vivo. The silencing of LMNB1 was found to significantly reduce the proliferation of human glioma cells, induce apoptosis in tumor cells, impede the progression of the cell cycle, and inhibit the migration of tumor cells. Consequently, we hypothesize that LMNB1 promotes glioma cell proliferation through mechanisms involving the inhibition of tumor cell apoptosis, acceleration of the cell cycle, and enhancement of tumor cell migration. We found that LMNB1 exert critical roles in glioma progression may via regulation of PI3K/Akt signaling pathway. These observations suggest that LMNB1 holds clinical potential for diagnostic and prognostic applications in glioma, presenting novel targets for drug development.

LMNB1 Duplication-Mediated Autosomal Dominant Adult-Onset Leukodystrophy in an Indian Family

Autosomal dominant leukodystrophy is an adult onset neurodegenerative disorder presenting with progressive symptoms of ataxia and autonomic dysfunction in fourth or fifth decade in life. It has clinical similarity with multiple sclerosis, but shows characteristic magnetic resonance imaging findings of diffuse bilaterally symmetrical leukodystrophy which can distinguish this disorder. It is a rare disorder with no known treatment till date, and has never been described from the Indian subcontinent. We present an Indian family with autosomal dominant adult-onset demyelinating leukodystrophy with multiple members affected over four generations, and demonstrate a cheap and accurate molecular method of real-time polymerase chain reaction to detect the LMNB1 gene duplication, which is the genetic basis of this devastating disorder.

Microarray analysis points to LMNB1 and JUN as potential target genes for predicting metastasis promotion by etoposide in colorectal cancer

Etoposide is a second-line chemotherapy agent widely used for metastatic colorectal cancer. However, we discovered that etoposide treatment induced greater motility potential in four colorectal cancer cell lines. Therefore, we used microarrays to test the mRNA of these cancer cell lines to investigate the mechanisms of etoposide promoting colorectal cancer metastasis. Differentially expressed genes (DEGs) were identified by comparing the gene expression profiles in samples from etoposide-treated cells and untreated cells in all four colorectal cancer cell lines. Next, these genes went through the Gene Set Enrichment Analysis (GSEA), Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) Pathway analysis. Among the top 10 genes including the upregulated and downregulated, eight genes had close interaction according to the STRING database: FAS, HMMR, JUN, LMNB1, MLL3, PLK2, STAG1 and TBL1X. After etoposide treatment, the cell cycle, metabolism-related and senescence signaling pathways in the colorectal cancer cell lines were significantly downregulated, whereas necroptosis and oncogene pathways were significantly upregulated. We suggest that the differentially expressed genes LMNB1 and JUN are potential targets for predicting colorectal cancer metastasis. These results provide clinical guidance in chemotherapy, and offer direction for further research in the mechanism of colorectal cancer metastasis.

Mechanism of LMNB1 activating GPR84 through JAK-STAT pathway to mediate M2 macrophage polarization in lung cancer

BACKGROUND

It is reported that G protein-coupled receptor 84 (GPR84) can participate in inflammation and immune regulation to repress anti-tumor responses. However, the function of GPR84 in lung cancer (LC) and its potential molecular mechanisms are still largely unknown.

METHODS

Bioinformatics and molecular experiments were employed to assess the expression of GPR84 in LC. The pathways enriched by GPR84 were analyzed by the Kyoto Encyclopedia of Genes and Genomes. Bioinformatics prediction identified the potential upstream regulatory factors of GPR84, which were verified through dual luciferase and chromatin immunoprecipitation experiments. Cell viability was measured by methyl thiazolyl tetrazolium assay. The expression levels of key proteins related to the janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway such as JAK2, p-JAK2, p-STAT3, and STAT3 were detected by western blot. Macrophages were co-cultured with LC cells. Flow cytometry was employed to examine the proportion of mannose receptor-positive cells. The expression levels of M2 polarization marker genes chitinase-like protein 3, arginase-1, and found in inflammatory zone 1 were measured by quantitative reverse transcription polymerase chain reaction. We applied an enzyme-linked immunosorbent assay to determine levels of cytokines (interleukin-10 and transforming growth factor beta) to evaluate the M2 macrophage polarization.

RESULTS

GPR84 was highly expressed in LC and substantially enriched in the JAK-STAT pathway. GPR84 facilitated the M2 polarization of macrophages in LC. Adding the JAK-STAT pathway inhibitor weakened the promoting effect of GPR84 overexpression on M2 macrophage polarization. Furthermore, GPR84 also had an upstream regulatory factor lamin B1 (LMNB1). Knocking down LMNB1 blocked the JAK-STAT signaling pathway to repress M2 macrophage polarization in LC, while overexpression of GPR84 reversed the impact of LMNB1 knockdown on macrophage polarization.

CONCLUSION

The project suggested that the LMNB1/GPR84 axis can facilitate M2 polarization of macrophages in LC by triggering the JAK-STAT pathway. Targeting LMNB1/GPR84 or blocking the JAK-STAT pathway may be a novel approach for LC diagnosis and treatment.

WTAP-mediated N6-methyladenosine modification promotes the inflammation, mitochondrial damage and ferroptosis of kidney tubular epithelial cells in acute kidney injury by regulating LMNB1 expression and activating NF-κB and JAK2/STAT3 pathways

Acute kidney injury (AKI) is a serious complication of sepsis patients, but the pathogenic mechanisms underlying AKI are still largely unclear. In this view, the roles of the key component of N6-methyladenosine (m6A)-wilms tumor 1 associated protein (WTAP) in AKI progression were investigated. AKI mice model was established by using cecal ligation and puncture (CLP). AKI cell model was established by treating HK-2 cells with LPS. Cell apoptosis was analyzed by TdT-mediated dUTP Nick-End Labeling (TUNEL) staining and flow cytometry analysis. Cell viability was analyzed by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay. The concentrations of inflammatory factors were examined with ELISA kits. Reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH) and Fe2+ levels were detected with related kits. Gene expression was detected by western blot assay or quantitative real-time polymerase chain reaction (qRT-PCR) assay. The relation between WTAP and lamin B1 (LMNB1) was verified by Methylated RNA Immunoprecipitation (meRIP) assay, RIP assay, dual-luciferase reporter assay and Actinomycin D assay. CLP induced significant pathological changes in kidney tissues in mice and promoted inflammation, mitochondrial damage and ferroptosis. LMNB1 level was induced in HK-2 cells by LPS. LMNB1 knockdown promoted LPS-mediated HK-2 cell viability and inhibited LPS-mediated HK-2 cell apoptosis, inflammation, mitochondrial damage and ferroptosis. Then, WTAP was demonstrated to promote LMNB1 expression by m6A Methylation modification. Moreover, WTAP knockdown repressed LPS-treated HK-2 cell apoptosis, inflammation, mitochondrial damage and ferroptosis, while LMNB1 overexpression reversed the effects. Additionally, WTAP affected the pathways of NF-κB and JAK2/STAT3 by LMNB1. WTAP-mediated m6A promoted the inflammation, mitochondrial damage and ferroptosis in LPS-induced HK-2 cells by regulating LMNB1 expression and activating NF-κB and JAK2/STAT3 pathways.

CircPTPRA promotes the progression of pancreatic ductal adenocarcinoma via the miR-140-5p/LMNB1 axis

BACKGROUND

Growing evidences suggest that circular RNAs (circRNAs) are important factors in cancer progression. Nevertheless, the role of circRNAs in the progression of pancreatic ductal adenocarcinoma (PDAC) remains unclear.

METHODS

CircPTPRA was identified based on our previous circRNA array data analysis. Wound healing, transwell, and EdU assays were performed to investigate the effect of circPTPRA on the migration, invasion, and proliferation of PDAC cells in vitro. RNA pull-down, fluorescence in situ hybridization (FISH), RNA immunoprecipitation (RIP), and dual-luciferase reporter assays were conducted to verify the binding of circPTPRA with miR-140-5p. Subcutaneous xenograft model was constructed for in vivo experiment.

RESULTS

CircPTPRA was significantly upregulated in PDAC tissues and cells compared to normal controls. Moreover, circPTPRA overexpression was positively correlated with lymph node invasion and worse prognosis in PDAC patients. In addition, overexpression of circPTPRA promoted PDAC migration, invasion, proliferation, and epithelial-mesenchymal transition (EMT) in vitro and in vivo. Mechanistically, circPTPRA upregulates LaminB1 (LMNB1) expression by sponging miR-140-5p and ultimately promotes the progression of PDAC.

CONCLUSIONS

This study revealed that circPTPRA plays an important role in the progression of PDAC by sponging miR-140-5p. It can be explored as a potential prognostic marker and therapeutic target for PDAC.