Unraveling the enigma: Molecular mechanisms of berberrubine-induced nephrotoxicity reversed by its parent form berberine

BACKGROUND

Berberine is an isoquinoline alkaloid that is extensively applied in the clinic due to its potential therapeutic effects on dysentery and infectious diarrhoea. Its main metabolite, berberrubine, a promising candidate for ameliorating hyperlipidaemia, has garnered more attention than berberine. However, our study revealed that berberrubine induces severe kidney damage, while berberine was proven to be safe.

PURPOSE

Herein, we explored the opposite biological effects of these two compounds on the kidney and elucidated their underlying mechanisms.

METHODS

First, integrated metabolomic and proteomic analyses were conducted to identify relevant signalling pathways. Second, a click chemistry method combined with a cellular thermal shiftassay, a drug affinity responsive target stability assay, and microscale thermophoresis were used to identify the direct target proteins. Moreover, a mutation experiment was performed to study the specific binding sites.

RESULTS

Animal studies showed that berberrubine, but not berberine, induced severe chronic, subchronic, and acute nephrotoxicity. More importantly, berberine reversed the berberrubine-reduced nephrotoxicity. The results indicated that the cPLA2 signalling pathway was highly involved in the nephrotoxicity induced by berberrubine. We further confirmed that the direct target of berberrubine is the BASP1 protein (an upstream factor of cPLA2 signalling). Moreover, berberine alleviated nephrotoxicity by binding cPLA2 and inhibiting cPLA2 activation.

CONCLUSION

This study is the first to revel the opposite biological effects of berberine and its metabolite berberrubine in inducing kidney injury. Berberrubine, but not berberine, shows strong nephrotoxicity. The cPLA2 signalling pathway can be activated by berberrubine through targeting of BASP1, while berberine inhibits this pathway by directly binding with cPLA2. Our study paves the way for studies on the exact molecular targets of herbal ingredients. We also demonstrated that natural small molecules and their active metabolites can have opposite regulatory roles in vivo through the same signalling pathway.

BASP1 down-regulates RANKL-induced osteoclastogenesis

The cytokine RANKL (Receptor Activator of NFκB Ligand) is the key driver of differentiation of monocytes/macrophages to form multi-nucleated, bone-resorbing osteoclasts, a process that is accompanied by significant changes in gene expression. We show that exposure to RANKL rapidly down-regulates expression of Brain Acid Soluble Protein 1 (BASP1) in cultured primary mouse bone marrow macrophages (BMMs), and that this reduced expression is causally linked to the osteoclastogenic process in vitro. Knocking down BASP1 expression in BMMs or eliminating its expression in these cells or in RAW 264.7 cells enhanced RANKL-induced osteoclastogenesis, promoted cell-cell fusion, and generated cultures containing larger osteoclasts with increased mineral degrading abilities relative to controls. Expression of exogenous BASP1 in BMMs undergoing osteoclastogenic differentiation produced the opposite effects. Upon exposure to RANKL, primary mouse BMMs in which BASP1 had been knocked down exhibited increased expression of the key osteoclastogenic transcription factor Nfatc1and of its downstream target genes Dc-stamp, Ctsk, Itgb3, and Mmp9 relative to controls. The knock-down cells also exhibited increased sensitivity to the pro-osteoclastogenic effects of RANKL. We conclude that BASP1 is a negative regulator of RANKL-induced osteoclastogenesis, which down-regulates the pro-osteoclastogenic gene expression pattern induced by this cytokine. Decreased expression of BASP1 upon exposure of BMMs to RANKL removes a negative regulator of osteoclastogenesis and promotes this process.

Circ_0008285 silencing suppresses angiotensin II-induced vascular smooth muscle cell apoptosis in thoracic aortic aneurysm via miR-150-5p/BASP1 axis

BACKGROUND

Vascular smooth muscle cells (VSMCs) are the predominant cell type of the aortic middle layer, the abnormal number or function of which has been demonstrated to have a role in thoracic aortic aneurysm (TAA). Here, this study aimed to identify the function of circ_0008285 in VSMC apoptosis.

METHODS

Human VSMCs were treated with angiotensin II (Ang II) for functional experiments. Cell counting kit-8, 5-ethynyl-2'-deoxyuridine (EdU), and flow cytometry were applied for function analysis. The interaction between miR-150-5p and circ_0008285 or brain acid-soluble protein 1 (BASP1) was also evaluated by dual-luciferase reporter assay and RNA immunoprecipitation assay. Exosomes were isolated by the commercial kit.

RESULTS

A highly expressed circ_0008285 was observed in the aortic tissues of TAA patients and Ang-II-induced VSMCs. Circ_0008285 deficiency dramatically reversed Ang-II-induced proliferation arrest and apoptosis promotion in VSMCs. Circ_0008285 functionally targeted miR-150-5p. MiR-150-5p inhibition attenuated the inhibitory effects of circ_0008285 silencing on Ang-II-evoked apoptosis in VSMCs. BASP1 was verified to be a target of miR-150-5p, and was proved to attenuate miR-150-5p-triggered apoptosis arrest in Ang-II-stimulated VSMCs. Additionally, extracellular circ_0008285 was packaged into exosomes, which could be transferred into the recipient cells.

CONCLUSION

Circ_0008285 silencing could suppress Ang-II-induced VSMCs apoptosis via miR-150-5p/BASP1 axis, adding further understanding of the pathogenesis of TAA.

BASP1 expression is associated with poor prognosis and is correlated with immune infiltration in gastric cancer

Basp1 is a membrane-bound protein that plays a promotional or inhibitory role in a variety of tumors; however, its role in gastric cancer (GC) and in the immune microenvironment has not been reported. The objectives of this study were to determine whether BASP1 is a valuable prognostic marker for GC and to explore its role in the immune microenvironment of GC. The expression level of BASP1 in GC was analyzed based on the TCGA dataset and further verified using GSE54129 and GSE161533 datasets, immunohistochemistry, and western blotting. The association between BASP1 and clinicopathological characteristics, as well as its predictive value, were examined using the STAD dataset. COX regression analysis was performed to determine whether BASP1 can be used as an independent prognostic indicator for GC, and a nomogram was constructed to predict OS. The association between BASP1 and immune cell infiltration, immune checkpoints, and immune cell markers was confirmed by enrichment analysis as well as analysis based on the TIMER and GEPIA databases. BASP1 was observed to be highly expressed in GC and was associated with a poor prognosis. The expression of BASP1 was positively correlated with the expression of immune checkpoints and immune cell markers as well as immune cell infiltration. Thus, BASP1 may serve as a standalone prognostic indicator for GC. BASP1 is highly correlated with immune processes, and its expression is positively correlated with the degree of immune cell infiltration, immune checkpoints, and immune cell markers.

BASP1 knockdown suppresses chondrocyte apoptosis and extracellular matrix degradation in vivo and in vitro: A possible therapeutic approach for osteoarthritis

Osteoarthritis(OA) is an age-related degenerative disease involving chondrocyte apoptosis and extracellular matrix(ECM) degradation.Brain acid soluble protein 1(BASP1) has been reported to induce apoptosis.Thus, we speculated that BASP1 might regulate OA progression by inducing apoptosis, which is also the purpose of this study.The cartilage of the knee joint was collected from OA patients who received the joint replacement.In OA cartilage tissue,we found BASP1 expression was highly expressed, which inferred that BASP1 might be involved in OA.To validate our hypothesis, destabilization of the medial meniscus (DMM) surgery-induced male C57BL/6mice and interleukin-1β (IL-1β)-treated human chondrocytes were used to mimic the OA environment.BASP1 knockdown in mice and chondrocytes was achieved by adenovirus carried with BASP1-specific shRNA.High expression of BASP1 was observed in OA mice, which was also verified in IL-1β-treated chondrocytes.The potential mechanism of BASP1 in OA was further explored in vitro.BASP1 knockdown alleviated IL-1β-induced apoptosis and ECM degradation, as reflected by the decreased number of apoptotic cells and matrix metalloproteases 13 expression,and the increased collagen II expression.Our findings indicated that BASP1 knockdown alleviated OA progression by inhibiting apoptosis and ECM degradation, suggesting that inhibiting BASP1 may be a potentially applicable method for preventing OA.

BASP1 promotes high glucose-induced endothelial apoptosis in diabetes via activation of EGFR signaling

AIMS

Diabetes mellitus is a common chronic disease of glucose metabolism. Endothelial dysfunction is an early event in diabetes complicated by cardiovascular disease. This study aimed to reveal the expression of BASP1 and its biological roles in endothelial cell dysfunction in diabetes complicated by cardiovascular disease.

MATERIALS AND METHODS

By analyzing the databases related to diabetes complicated with coronary heart disease, BASP1 was screened out as an upregulated gene. Human umbilical vein endothelial cells (HUVECs) and primary mouse aortic endothelial cells were treated with high glucose to establish cell models of diabetes-related endothelial dysfunction, and the expression changes of BASP1 were verified by RT-qPCR, western blot, and immunofluorescence. BASP1 was silenced or overexpressed by siRNA or overexpression plasmid, and its effects on cell migration, apoptosis, tube formation, inflammatory response, and ROS were detected. The possible signaling pathway of BASP1 was found and the mechanism of BASP1 on promoting the progression of endothelial dysfunction was explored using the EGFR inhibitor, gefitinib.

RESULTS

Bioinformatics analysis indicated that the expression of BASP1 in patients with diabetes mellitus and concomitant coronary heart disease was increased. High glucose induced the upregulation of BASP1 expression in endothelial cells, and showed a time-dependent relationship. Silencing of BASP1 alleviated the damage of high glucose to endothelial cells. BASP1 regulated EGFR positively. The promoting effect of BASP1 on endothelial cell apoptosis may be achieved by regulating the EGFR pathway.

CONCLUSION

BASP1 promotes endothelial cell injury induced by high glucose in patients with diabetes, which may be activated by activating the EGFR pathway.

BASP1 is a prognostic biomarker associated with immunotherapeutic response in head and neck squamous cell carcinoma

Backgrounds

Immunotherapy is effective in a subset of head and neck squamous cell carcinoma (HNSCC). However, the unfavorable response rate and inadequate biomarkers for stratifying patients have primarily limited its clinical application. Considering transcriptional factors (TFs) play essential roles in regulating immune activity during HNSCC progression, we comprehensively analyzed the expression alterations of TFs and their prognostic values.

Methods

Gene expression datasets and clinical information of HNSCC were obtained from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) repository. Then, Brain abundant membrane attached signal protein 1 (BASP1) was screened out of differentially expressed TFs by univariate and multivariate survival analysis. Tumor immune dysfunction and exclusion (TIDE) was applied to analyze the response to immunotherapy of BASP1^high/low patients. Meanwhile, GO, KEGG and GSEA analyses were used to enrich the pathways between the BASP1^high and BASP1^low groups. Single-sample gene set enrichment analysis (ssGSEA), CIBERSORT, EPIC and quanTiseq algorithms were applied to explore immune infiltrations. Also, immune cycle analysis was conducted by ssGSEA. Additionally, lipid peroxidation, glutathione and reactive oxygen species were performed to detect the ferroptosis alternations.

Results

BASP1 was upregulated and associated with poor survival in HNSCC patients. BASP1^high patients exhibited better response rates to anti-PD-1 immunotherapy and higher expressions of immune checkpoint inhibitors. GO, KEGG and GSEA analyses indicated that the expression of BASP1 was related to several immune-related pathways and immunogenic ferroptosis signature. The infiltration of activated CD8⁺ T cells was authenticated to be decreased in BASP1^high patients. Furthermore, BASP1 was identified to be positively correlated with T cell dysfunction and immune escape. Moreover, silencing BASP1 triggered ferroptosis in HNSCC cells, representing as increased LDH, lipid peroxidation and ROS levels, and reduced glutathione synthesis.

Conclusions

We demonstrated that BASP1 suppressed immunogenic ferroptosis to induce immunosuppressive tumor microenvironment. BASP1 plays a critical role in immune response, and might be a promising classifier for selecting HNSCC patients who benefit from current immunotherapy.

A high-affinity cocaine binding site associated with the brain acid soluble protein 1

Cocaine is a monoamine transport inhibitor. Current models attributing pharmacologic actions of cocaine to inhibiting the activity of the amine transporters alone failed to translate to the clinic. Cocaine inhibition of the dopamine, serotonin, and norepinephrine transporters is relatively weak, suggesting that blockade of the amine transporters alone cannot account for the actions of cocaine, especially at low doses. There is evidence for significantly more potent actions of cocaine, suggesting the existence of a high-affinity receptor(s) for the drug. Identifying and characterizing such receptors will deepen our understanding of cocaine pharmacologic actions and pave the way for therapeutic development. Here we identify a high-affinity cocaine binding site associated with BASP1 that is involved in mediating the drug’s psychotropic actions.

Cocaine exerts its stimulant effect by inhibiting dopamine (DA) reuptake, leading to increased dopamine signaling. This action is thought to reflect the binding of cocaine to the dopamine transporter (DAT) to inhibit its function. However, cocaine is a relatively weak inhibitor of DAT, and many DAT inhibitors do not share cocaine’s behavioral actions. Further, recent reports show more potent actions of the drug, implying the existence of a high-affinity receptor for cocaine. We now report high-affinity binding of cocaine associated with the brain acid soluble protein 1 (BASP1) with a dissociation constant (K_d) of 7 nM. Knocking down BASP1 in the striatum inhibits [³H]cocaine binding to striatal synaptosomes. Depleting BASP1 in the nucleus accumbens but not the dorsal striatum diminishes locomotor stimulation in mice. Our findings imply that BASP1 is a pharmacologically relevant receptor for cocaine.

LINC00599 influences smoke-related chronic obstructive pulmonary disease and regulates CSE-induced epithelial cell apoptosis and inflammation by targeting miR-212-5p/BASP1 axis

LINC00599 has been reported to be upregulated in response to cigarette smoking. However, the effect and underlying mechanism of LINC00599 in chronic obstructive pulmonary disease (COPD) are still under exploration. In this study, LINC00599 was upregulated in the COPD patients and was of clinical value to distinguish COPD patients. COPD cell models were established using 16HBE cells under cigarette smoke extract (CSE) treatment. LINC00599 levels were elevated in a dose and time-dependent way in response to CSE stimulation. The effect of LINC00599 on CSE-induced 16HBE cells was explored. The results showed that LINC00599 deficiency reversed the CSE-induced inhibition on cell viability and proliferation, and rescued the CSE-induced enhancement on cell 16HBE cell apoptosis and inflammation response. Moreover, LINC00599 bound with miR-212-5p to upregulate the BASP1 (brain abundant membrane attached signal protein 1) expression. MiR-212-5p was expressed at a low level in the tissue samples of COPD patients, and its levels were upregulated in LINC00599 silenced cells. BASP1 was targeted by miR-212-5p and its upregulation was identified in the tissue samples of COPD patients and cell models. BASP1 levels were downregulated after miR-212-5p overexpression or LINC00599 silencing. Moreover, the rescue assays demonstrated that BASP1 overexpression reversed the effect of silenced LINC00599 on 16HBE cells after CSE treatment, which indicated that LINC00599 promoted the COPD development by regulating BASP1 expression. In conclusion, LINC00599 facilitated CSE-induced cell apoptosis and inflammation response, while inhibiting the cell viability and proliferation in COPD progression via modulating miR-212-5p/BASP1 axis.

Garlic exosome-like nanoparticles reverse high-fat diet induced obesity via the gut/brain axis

Background: Obesity is becoming a global epidemic and reversing the pathological processes underlying obesity and metabolic co-morbidities is challenging. Obesity induced chronic inflammation including brain inflammation is a hallmark of obesity via the gut-brain axis. The objective of this study was to develop garlic exosome-like nanoparticles (GaELNs) that inhibit systemic as well as brain inflammatory activity and reverse a HFD induced obesity in mice.

Methods: GELNs were isolated and administrated orally into HFD fed mice. GaELNs were fluorescent labeled for monitoring their in vivo trafficking route after oral administration and quantified the number particles in several tissues. The brain inflammation was determined by measuring inflammatory cytokines by ELISA and real-time PCR. Mitochondrial membrane permeability of microglial cells was determined using JC-10 fluorescence dye. The in vivo apoptotic cell death was quantified by TUNEL assay. The brain metabolites were identified and quantified by LC-MS analysis. Memory function of the mice was determined by several memory functional analysis. The effect of GaELNs on glucose and insulin response of the mice was determined by glucose and insulin tolerance tests. c-Myc localization and interaction with BASP1 and calmodulin was determined by confocal microscopy.

Results: Our results show that GaELNs is preferentially taken up microglial cells and inhibits the brain inflammation in HFD mice. GaELN phosphatidic acid (PA) (36:4) is required for the uptake of GaELNs via interaction with microglial BASP1. Formation of the GaELNs/BASP1 complex is required for inhibition of c-Myc mediated expression of STING. GaELN PA binds to BASP1, leading to inhibition of c-Myc expression and activity through competitively binding to CaM with c-Myc transcription factor. Inhibition of STING activity leads to reducing the expression of an array of inflammatory cytokines including IFN-γ and TNF-α. IFN-γ induces the expression of IDO1, which in turn the metabolites generated as IDO1 dependent manner activate the AHR pathway that contributes to developing obesity. The metabolites derived from the GaELNs treated microglial cells promote neuronal differentiation and inhibit mitochondrial mediated neuronal cell death. GaELNs treated HFD mice showed improved memory function and increased glucose tolerance and insulin sensitivity in these mice.

Conclusion: Collectively, these results demonstrate how nanoparticles from a healthy diet can inhibit unhealthy high-fat diet induced brain inflammation and reveal a link between brain microglia/diet to brain inflammatory disease outcomes via diet-derived exosome-like nanoparticles.

BASP1 is up-regulated in tongue squamous cell carcinoma and associated with a poor prognosis

OBJECTIVE

To study the relationship between expression of brain acid soluble protein 1 (BASP1) in tongue squamous cell carcinoma (TSCC) tissue and the clinicopathological characteristics and prognosis of patients with TSCC.

METHODS

Western blotting was performed to detect BASP1 expression in fresh-frozen specimens of tumor tissue and adjacent normal tissue obtained from 6 patients with TSCC. Immunohistochemical methods were used to detect BASP1 expression in 100 paraffin-embedded specimens of TSCC tissue. The chi-square test was used to analyze the association between BASP1 expression and a variety of clinicopathological parameters. A Kaplan-Meier analysis and the Cox proportional hazard model were used to further evaluate the impact of BASP1 on patient survival.

RESULTS

The Oncomine database showed that BASP1 expression was increased in TSCC tissues. The PrognoScan and GEPIA databases suggested that a high level of BASP1 expression is related to a poor prognosis for patients with head and neck cancer. Experimental results showed that when compared to normal tissues adjacent to a cancer, BASP1 was more highly expressed in the TSCC tissues. Univariate and multivariate Cox regression analyses showed that BASP1 expression and the tumor's stage may be independent risk factors that affect the growth and prognosis of TSCC. A survival analysis showed that patients with a low level of BASP1 expression had a higher survival rate.

CONCLUSION

Overexpression of BASP1 was found to be associated with distant node metastasis and a poor prognosis among patents with TSCC. BASP1 could possibly serve as a molecular marker for diagnosing and treating the disease.

Cholesterol is required for transcriptional repression by BASP1

Cholesterol is present within the cell nucleus, where it associates with chromatin, but to date, a direct role for cholesterol in nuclear processes has not been identified. We demonstrate that the transcriptional repressor brain acid soluble protein 1 (BASP1) directly interacts with cholesterol within the cell nucleus through a consensus cholesterol interaction motif. BASP1 recruits cholesterol to the promoter region of target genes, where it is required to mediate chromatin remodeling and transcriptional repression. Our work demonstrates that cholesterol plays a direct role in transcriptional regulation.

Lipids are present within the cell nucleus, where they engage with factors involved in gene regulation. Cholesterol associates with chromatin in vivo and stimulates nucleosome packing in vitro, but its effects on specific transcriptional responses are not clear. Here, we show that the lipidated Wilms tumor 1 (WT1) transcriptional corepressor, brain acid soluble protein 1 (BASP1), interacts with cholesterol in the cell nucleus through a conserved cholesterol interaction motif. We demonstrate that BASP1 directly recruits cholesterol to the promoter region of WT1 target genes. Mutation of BASP1 to ablate its interaction with cholesterol or the treatment of cells with drugs that block cholesterol biosynthesis inhibits the transcriptional repressor function of BASP1. We find that the BASP1–cholesterol interaction is required for BASP1-dependent chromatin remodeling and the direction of transcription programs that control cell differentiation. Our study uncovers a mechanism for gene-specific targeting of cholesterol where it is required to mediate transcriptional repression.

Podocyte apoptosis in diabetic nephropathy by BASP1 activation of the p53 pathway via WT1

AIMS

Diabetic nephropathy (DN) is a leading cause of end-stage renal disease. BASP1 (brain acid-soluble protein) is up-regulated in podocyte-specific protein phosphatase 2A knockout mice (Pod-PP2A-KO) that develop kidney dysfunction. Here, we explore the role of BASP1 for podocytes in DN.

METHODS

BASP1 was assessed in kidneys from DN patients and DN mouse models, podocyte specific BASP1 knockout mice (Pod-BASP1-KO mice) were generated and studied in vivo. Furthermore, podocyte injury and apoptosis were measured after BASP1 knockdown and overexpression in a mouse podocyte cell line (MPC5). Potential signalling pathways involved in podocyte apoptosis were detected.

RESULTS

BASP1 expression was up-regulated in DN patients compared to normal controls. BASP1 specific deletion in podocytes protected against podocyte injury by reducing the loss of expression of slit diaphragm molecules and foot process effacement in the DN model. BASP1 promoted actin cytoskeleton rearrangements and apoptosis in the MPC5 podocyte line. Molecules involved in the p53 pathway were down-regulated in BASP1 knockdown podocytes treated with high glucose compared to controls. BASP1 promoted podocyte apoptosis and P53 pathway activation through co-repression with Wilms' tumour 1 transcription factor (WT1).

CONCLUSION

BASP1 activates the p53 pathway through modulation of WT1 to induce podocyte apoptosis in diabetic nephropathy.

High BASP1 Expression is Associated with Poor Prognosis and Promotes Tumor Progression in Human Lung Adenocarcinoma

BASP1 is involved in signal transduction and cytoskeleton formation and plays a tumor-promoting or tumor-suppressing role in cancers. We found BASP1 was overexpressed in lung adenocarcinoma tissues and promoted the proliferation and migration of lung adenocarcinoma cells. The mechanism may be related to inhibition of cell apoptosis and abnormal activation of the Wnt/β-catenin pathway and epithelial-mesenchymal transformation. BASP1 is associated with poor prognosis in lung adenocarcinoma.

Truncated YY1 interacts with BASP1 through a 339KLK341 motif in YY1 and suppresses vascular smooth muscle cell growth and intimal hyperplasia after vascular injury

AIMS

In-stent restenosis and late stent thrombosis are complications associated with the use of metallic and drug-coated stents. Strategies that inhibit vascular smooth muscle cell (SMC) proliferation without affecting endothelial cell (EC) growth would be helpful in reducing complications arising from percutaneous interventions. Our group previously showed that the forced expression of the injury-inducible zinc finger (ZNF) transcription factor, yin yang-1 (YY1) comprising 414 residues inhibits neointima formation in carotid arteries of rabbits and rats. YY1 inhibits SMC proliferation without affecting EC growth. Identifying a shorter version of YY1 retaining cell-selective inhibition would make it more amenable for potential use as a gene therapeutic agent.

METHODS AND RESULTS

We dissected YY1 into a range of shorter fragments (YY1A-D, YY1Δ) and found that the first two ZNFs in YY1 (construct YY1B, spanning 52 residues) repressed SMC proliferation. Receptor Binding Domain analysis predicts a three residue (339KLK341) interaction domain. Mutation of 339KLK341 to 339AAA341 in YY1B (called YY1Bm) abrogated YY1B's ability to inhibit SMC but not EC proliferation and migration. Incubation of recombinant GST-YY1B and GST-YY1Bm with SMC lysates followed by precipitation with glutathione-agarose beads and mass spectrometric analysis identified a novel interaction between YY1B and BASP1. Overexpression of BASP1, like YY1, inhibited SMC but not EC proliferation and migration. BASP1 siRNA partially rescued SMC from growth inhibition by YY1B. In the rat carotid balloon injury model, adenoviral overexpression of YY1B, like full-length YY1, reduced neointima formation, whereas YY1Bm had no such effect. CD31 immunostaining suggested YY1B could increase re-endothelialization in a 339KLK341-dependent manner.

CONCLUSIONS

These studies identify a truncated form of YY1 (YY1B) that can interact with BASP1 and inhibits SMC proliferation, migration and intimal hyperplasia after balloon injury of rat carotid arteries as effectively as full length YY1. We demonstrate the therapeutic potential of YY1B in vascular proliferative disease.

A versatile platform for generating engineered extracellular vesicles with defined therapeutic properties

Extracellular vesicles (EVs) are an important intercellular communication system facilitating the transfer of macromolecules between cells. Delivery of exogenous cargo tethered to the EV surface or packaged inside the lumen are key strategies for generating therapeutic EVs. We identified two “scaffold” proteins, PTGFRN and BASP1, that are preferentially sorted into EVs and enable high-density surface display and luminal loading of a wide range of molecules, including cytokines, antibody fragments, RNA binding proteins, vaccine antigens, Cas9, and members of the TNF superfamily. Molecules were loaded into EVs at high density and exhibited potent in vitro activity when fused to full-length or truncated forms of PTGFRN or BASP1. Furthermore, these engineered EVs retained pharmacodynamic activity in a variety of animal models. This engineering platform provides a simple approach to functionalize EVs with topologically diverse macromolecules and represents a significant advance toward unlocking the therapeutic potential of EVs.

Overexpression of BASP1 Indicates a Poor Prognosis in Head and Neck Squamous Cell Carcinoma

Objective:

Brain abundant membrane attached signal protein 1 (BASP1) was originally identified as a membrane and cytoplasmic protein. Recent studies have shown that BASP1 highly expressed in cancer and promoted the proliferation of cancer. However, the role of BASP1 in head and neck squamous cell carcinoma (HNSCC) is largely unknown. Here, we performed a systematic data analysis to examine whether BASP1 can function as prognostic marker in HNSCC.

Methods:

In this study, we used Oncomine, and UALCAN, databases to analyze the expression of BASP1 in HNSCC. We used Kaplan-Meier plotter to evaluate the effect of BASP1 on clinical prognosis. In addition, we also analyzed genetic alterations, interaction network, and functional enrichment of BASP1.

Results:

BASP1 mRNA expression level was remarkably increased in HNSCC than in normal tissues (P=1.624e-12). Moreover, high BASP1 expression was significantly related to poor survival (p=0.00056) in HNSCC patients. In addition, BASP1 gene amplified in 5% of HNSCC patients which contributes to the overexpression of BASP1.

Conclusions:

These findings suggest that BASP1 was frequently amplified which contributes to the overexpression of BASP1, thereby promoting HNSCC progression. Thus, these results indicate that BASP1 might serve as a biomarker to predict the progression and prognosis of HNSCC patients.

WT1 activates transcription of the splice factor kinase SRPK1 gene in PC3 and K562 cancer cells in the absence of corepressor BASP1

Dysregulated alternative splicing plays a prominent role in all hallmarks of cancer. The splice factor kinase SRPK1 drives the activity of oncogenic splice factors such as SRSF1. SRSF1 in turn promotes the expression of splice isoforms that favour tumour growth, including proangiogenic VEGF. Knockdown (with siRNA) or chemical inhibition (using SPHINX) of SRPK1 in K562 leukemia and PC3 prostate cancer cell lines reduced cell proliferation, invasion and migration. In glomerular podocytes, the Wilms tumour suppressor zinc-finger transcription factor WT1 represses SRPK1 transcription. Here we show that in cancer cells WT1 activates SRPK1 transcription, unless a canonical WT1 binding site adjacent to the transcription start site is mutated. The ability of WT1 to activate SRPK1 transcription was reversed by the transcriptional corepressor BASP1, and both WT1 and BASP1 co-precipitated with the SRPK1 promoter. BASP1 significantly increased the expression of the antiangiogenic VEGF₁₆₅b splice isoform. We propose that by upregulating SRPK1 transcription WT1 can direct an alternative splicing landscape that facilitates tumour growth.

GAP-43 and BASP1 in Axon Regeneration: Implications for the Treatment of Neurodegenerative Diseases

Growth-associated protein-43 (GAP-43) and brain acid-soluble protein 1 (BASP1) regulate actin dynamics and presynaptic vesicle cycling at axon terminals, thereby facilitating axonal growth, regeneration, and plasticity. These functions highly depend on changes in GAP-43 and BASP1 expression levels and post-translational modifications such as phosphorylation. Interestingly, examinations of GAP-43 and BASP1 in neurodegenerative diseases reveal alterations in their expression and phosphorylation profiles. This review provides an overview of the structural properties, regulations, and functions of GAP-43 and BASP1, highlighting their involvement in neural injury response and regeneration. By discussing GAP-43 and BASP1 in the context of neurodegenerative diseases, we also explore the therapeutic potential of modulating their activities to compensate for neuron loss in neurodegenerative diseases.

Targeting positive feedback between BASP1 and EGFR as a therapeutic strategy for lung cancer progression

Rationale: Brain metastasis in patients with lung cancer is life-threatening. However, the molecular mechanism for this catastrophic disease remains elusive, and few druggable targets are available. Therefore, this study aimed to identify and characterize proteins that could be used as therapeutic targets.

Methods: Proteomic analyses were conducted to identify differentially expressed membrane proteins between brain metastatic lung cancer cells and primary lung cancer cells. A neuronal growth-associated protein, brain acid soluble protein 1 (BASP1), was chosen for further investigation. The clinical relevance of BASP1 in lung adenocarcinoma was first assessed. Tyrosine kinase activity assays and in vitro and in vivo functional assays were conducted to explore the oncogenic mechanisms of BASP1.

Results: The protein levels of BASP1 were positively associated with tumor progression and poor prognosis in patients with lung adenocarcinoma. Membrane-bound BASP1 increased EGFR signaling and stabilized EGFR proteins by facilitating their escape from the ubiquitin-proteasome pathway. Reciprocally, activation of EGFR recruited more BASP1 to the plasma membrane, generating a positive feedback loop between BASP1 and EGFR. Moreover, the synergistic therapeutic effects of EGFR tyrosine kinase inhibitor and arsenic trioxide led to a reduction in the level of BASP1 protein observed in lung cancer cells with acquired resistance to EGFR inhibitors.

Conclusions: The reciprocal interaction between BASP1 and EGFR facilitates EGFR signaling in brain metastatic lung cancer. Targeting the newly identified BASP1-EGFR interaction could open new venues for lung cancer treatment.

LINC00473 inhibits vascular smooth muscle cell viability to promote aneurysm formation via miR-212-5p/BASP1 axis

Abdominal aortic aneurysm (AAA), as the most common type of aortic aneurysm, is closely related to the proliferation and apoptosis ability of vascular smooth muscle cells (VSMCs). Long non-coding RNAs (lncRNAs) are emerging regulators in disease development. LncRNA LINC00473 has been shown to affect cell proliferation and apoptosis in various cancers, but its role in AAA is still blank. In this work, in vitro AAA models were successfully established since cell viability was inhibited whereas apoptosis stimulated in VSMCs treated with H₂O₂. LINC00473 was up-regulated in VSMCs after H₂O₂ treatment. Overexpression of LINC00473 inhibited VSMC cell proliferation and promoted cell apoptosis and its silence mitigated H₂O₂-induced injuries to VSMCs. Additionally, we uncovered that LINC00473 sponged miR-212-5p to regulate brain acid soluble protein 1 (BASP1) expression. Finally, rescue assays uncovered that overexpression of miR-212-5p or suppression of BASP1 reversed the effects of LINC00473 up-regulation on cell proliferation and cell apoptosis. And the positive correlation between LINC00473 and BASP1 as well as the negative relation of miR-212-5p to both LINC00473 and BASP1 were confirmed in AAA tissues. All finding illuminated that LINC00473 participated in AAA development by regulating miR-212-5p/BASP1 pathway, suggesting LINC00473 as a promising target for AAA therapy.

Quantitative proteomics identifies brain acid soluble protein 1 (BASP1) as a prognostic biomarker candidate in pancreatic cancer tissue

BACKGROUND

Pancreatic cancer is a heterogenous disease with a poor prognosis. This study aimed to discover and validate prognostic tissue biomarkers in pancreatic cancer using a mass spectrometry (MS) based proteomics approach.

METHODS

Global protein sequencing of fresh frozen pancreatic cancer and healthy pancreas tissue samples was conducted by MS to discover potential protein biomarkers. Selected candidate proteins were further verified by targeted proteomics using parallel reaction monitoring (PRM). The expression of biomarker candidates was validated by immunohistochemistry in a large tissue microarray (TMA) cohort of 141 patients with resectable pancreatic cancer. Kaplan-Meier and Cox proportional hazard modelling was used to investigate the prognostic utility of candidate protein markers.

FINDINGS

In the initial MS-discovery phase, 165 proteins were identified as potential biomarkers. In the subsequent MS-verification phase, a panel of 45 candidate proteins was verified by the development of a PRM assay. Brain acid soluble protein 1 (BASP1) was identified as a new biomarker candidate for pancreatic cancer possessing largely unknown biological and clinical functions and was selected for further analysis. Importantly, bioinformatic analysis indicated that BASP1 interacts with Wilms tumour protein (WT1) in pancreatic cancer. TMA-based immunohistochemistry analysis showed that BASP1 was an independent predictor of prolonged survival (HR 0.468, 95% CI 0.257-0.852, p = .013) and predicted favourable response to adjuvant chemotherapy, whereas WT1 indicated a worsened survival (HR 1.636, 95% CI 1.083-2.473, p = .019) and resistance to chemotherapy. Interaction analysis showed that patients with negative BASP1 and high WT1 expression had the poorest outcome (HR 3.536, 95% CI 1.336-9.362, p = .011).

INTERPRETATION

We here describe an MS-based proteomics platform for developing biomarkers for pancreatic cancer. Bioinformatic analysis and clinical data from our study suggest that BASP1 and its putative interaction partner WT1 can be used as biomarkers for predicting outcomes in pancreatic cancer patients.

A Unique Family of Neuronal Signaling Proteins Implicated in Oncogenesis and Tumor Suppression

The neuronal proteins GAP43 (neuromodulin), MARCKS, and BASP1 are highly expressed in the growth cones of nerve cells where they are involved in signal transmission and cytoskeleton organization. Although their primary structures are unrelated, these signaling proteins share several structural properties like fatty acid modification, and the presence of cationic effector domains. GAP43, MARCKS, and BASP1 bind to cell membrane phospholipids, a process reversibly regulated by protein kinase C-phosphorylation or by binding to the calcium sensor calmodulin (CaM). GAP43, MARCKS, and BASP1 are also expressed in non-neuronal cells, where they may have important functions to manage cytoskeleton architecture, and in case of MARCKS and BASP1 to act as cofactors in transcriptional regulation. During neoplastic cell transformation, the proteins reveal differential expression in normal vs. tumor cells, and display intrinsic tumor promoting or tumor suppressive activities. Whereas GAP43 and MARCKS are oncogenic, tumor suppressive functions have been ascribed to BASP1 and in part to MARCKS depending on the cell type. Like MARCKS, the myristoylated BASP1 protein is localized both in the cytoplasm and in the cell nucleus. Nuclear BASP1 participates in gene regulation converting the Wilms tumor transcription factor WT1 from an oncoprotein into a tumor suppressor. The BASP1 gene is downregulated in many human tumor cell lines particularly in those derived from leukemias, which display elevated levels of WT1 and of the major cancer driver MYC. BASP1 specifically inhibits MYC-induced cell transformation in cultured cells. The tumor suppressive functions of BASP1 and MARCKS could be exploited to expand the spectrum of future innovative therapeutic approaches to inhibit growth and viability of susceptible human tumors.

High brain acid soluble protein 1(BASP1) is a poor prognostic factor for cervical cancer and promotes tumor growth

Background

The aim of this study was to determine whether brain abundant membrane attached signal protein 1 (BASP1) is a valuable prognostic biomarker for cervical cancer and whether BASP1 regulates the progression of cervical cancer.

Methods

Quantitative real-time PCR, western blotting, and immunohistochemistry were used to determined BASP1 levels. Statistical analyses were used to examine whether BASP1 was a prognostic factor for patients with cervical cancer. The MTT assay, colony formation assay, cell cycle assay, anchorage-independent growth assay, and a tumor xenograft model were used to determine the role of BASP1 in the proliferation and tumorigenicity of cervical cancer.

Results

Brain abundant membrane attached signal protein 1 was upregulated in cervical cancer tissues and cells, and BASP1 expression levels were higher in patients that had died during follow-up compared with those that survived. There was a positive correlation between BASP1 expression and clinical stage (p < 0.001), T classification (p < 0.001), N classification (p < 0.05), and survival or mortality (p < 0.05). Patients with higher BASP1 expression had a shorter overall survival time. Cox regression analysis shown BSAP1 was an unfavorable prognostic factor for patients with cervical cancer. Overexpression of BASP1 promoted the proliferation of cervical cancer and its colony formation ability, accelerated cell cycle progression, and enhanced tumorgenicity. BASP1 knockdown inhibited the proliferation of cervical cancer and its colony formation ability, suppressed cell cycle progression, and decreased tumorgenicity.

Conclusions

The results showed that BASP1 not only is a novel prognostic factor for patients with cervical cancer, but also promotes the proliferation and tumorigenicity of cervical cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s12935-017-0452-4) contains supplementary material, which is available to authorized users.

Two-stage genome-wide association study identifies a novel susceptibility locus associated with melanoma

Genome-wide association studies have identified 21 susceptibility loci associated with melanoma. These loci implicate genes affecting pigmentation, nevus count, telomere maintenance, and DNA repair in melanoma risk. Here, we report the results of a two-stage genome-wide association study of melanoma. The stage 1 discovery phase consisted of 4,842 self-reported melanoma cases and 286,565 controls of European ancestry from the 23andMe research cohort and the stage 2 replication phase consisted of 1,804 melanoma cases and 1,026 controls from the University of Texas M.D. Anderson Cancer Center. We performed a combined meta-analysis totaling 6,628 melanoma cases and 287,591 controls. Our study replicates 20 of 21 previously known melanoma-loci and confirms the association of the telomerase reverse transcriptase, TERT, with melanoma susceptibility at genome-wide significance. In addition, we uncover a novel polymorphism, rs187843643 (OR = 1.96; 95% CI = [1.54, 2.48]; P = 3.53 × 10⁻⁸), associated with melanoma. The SNP rs187842643 lies within a noncoding RNA 177kb downstream of BASP1 (brain associated protein-1). We find that BASP1 expression is suppressed in melanoma as compared with benign nevi, providing additional evidence for a putative role in melanoma pathogenesis.

In Vitro Transcription to Study WT1 Function

In vitro transcription methods using mammalian nuclear extracts have been available for over 30 years and have allowed sophisticated biochemical analyses of the transcription process. This method has been extensively used to study the basic mechanisms of transcription, allowing the identification of the general transcription factors and elucidation of their mechanisms of action. Gene-specific transcriptional regulators have also been studied using in vitro transcription. This has facilitated the identification of their cofactors and provided information on their function that is invaluable to facilitate their study in a more physiological setting. Here we describe the application of in vitro transcription methods to study the mechanism of action of WT1. Coupling transcription assays with methods to purify transcription complexes, and protein affinity chromatography, has provided insights into how WT1 can both positively and negatively regulate transcription.