Spon1+ inflammatory monocytes promote collagen remodeling and lung cancer metastasis through lipoprotein receptor 8 signaling.

Lung cancer is the leading cause of cancer-related deaths in the world, and non-small cell lung cancer (NSCLC) is the most common subset. We previously found that infiltration of tumor inflammatory monocytes (TIMs) into lung squamous carcinoma (LUSC) tumors is associated with increased metastases and poor survival. To further understand how TIMs promote metastases, we compared RNA-Seq profiles of TIMs from several LUSC metastatic models with inflammatory monocytes (IMs) of non-tumor-bearing controls. We identified Spon1 as upregulated in TIMs and found that Spon1 expression in LUSC tumors corresponded with poor survival and enrichment of collagen extracellular matrix signatures. We observed SPON1+ TIMs mediate their effects directly through LRP8 on NSCLC cells, which resulted in TGF-ß1 activation and robust production of fibrillar collagens. Using several orthogonal approaches, we demonstrated that SPON1+ TIMs were sufficient to promote NSCLC metastases. Additionally, we found that Spon1 loss in the host, or Lrp8 loss in cancer cells, resulted in a significant decrease of both high-density collagen matrices and metastases. Finally, we confirmed the relevance of the SPON1/LRP8/TGF-ß1 axis with collagen production and survival in patients with NSCLC. Taken together, our study describes how SPON1+ TIMs promote collagen remodeling and NSCLC metastases through an LRP8/TGF-ß1 signaling axis.

LRP8 promotes tumorigenesis in ovarian cancer through inhibiting p53 signaling.

Ovarian cancer (OC) is the most lethal gynecological malignancy with a high mortality rate. Low-density lipoprotein (LDL) receptor-related protein 8 (LRP8) is a cell membrane receptor belonging LDL receptor family and is involved in several tumor progressions. However, there is limited understanding of how LRP8 mediates OC development. LRP8 expression level was identified in human OC tissues and cells using immunohistochemical staining and quantitative polymerase chain reaction assays, respectively. Functions of LRP8 in OC progression were evaluated by Celigo cell counting, wound healing, transwell and flow cytometry assays, and the xenograft models. The human phospho-kinase array analysis was used for screening potential signaling involved in OC development. We observed that LRP8 was overexpressed in OC tissues, and high expression of LRP8 was associated with poor prognosis of OC patients. Functionally, LRP8 knockdown remarkably reduced proliferation and migration of OC cells, and induced apoptosis and S phase cycle arrest. LRP8 deficiency attenuated in vivo tumor growth of OC cells. Moreover, the addition of p53 inhibitor partially reversed the effects of LRP8 knockdown on OC cell proliferation and apoptosis, indicating the involvement of p53 signaling in LRP8-mediated OC progression. This study confirmed that LRP8/p53 axis contributed to OC progression, which might serve as a novel potential therapeutic target for OC patients.

Reelin through the years: From brain development to inflammation.

Reelin was originally identified as a regulator of neuronal migration and synaptic function, but its non-neuronal functions have received far less attention. Reelin participates in organ development and physiological functions in various tissues, but it is also dysregulated in some diseases. In the cardiovascular system, Reelin is abundant in the blood, where it contributes to platelet adhesion and coagulation, as well as vascular adhesion and permeability of leukocytes. It is a pro-inflammatory and pro-thrombotic factor with important implications for autoinflammatory and autoimmune diseases such as multiple sclerosis, Alzheimer's disease, arthritis, atherosclerosis, or cancer. Mechanistically, Reelin is a large secreted glycoprotein that binds to several membrane receptors, including ApoER2, VLDLR, integrins, and ephrins. Reelin signaling depends on the cell type but mostly involves phosphorylation of NF-κB, PI3K, AKT, or JAK/STAT. This review focuses on non-neuronal functions and the therapeutic potential of Reelin, while highlighting secretion, signaling, and functional similarities between cell types.

SORL1 stabilizes ABCB1 to promote cisplatin resistance in ovarian cancer.

Ovarian cancer (OC) has the worst prognosis among gynecological malignancies. Cisplatin (CDDP) is one of the most commonly used treatments for OC, but recurrence and metastasis are common due to endogenous or acquired resistance. High expression of ATP-binding cassette (ABC) transporters is an important mechanism of resistance to OC chemotherapy, but targeting ABC transporters in OC therapy remains a challenge. The expression of sortilin-related receptor 1 (SORL1; SorLA) in the response of OC to CDDP was determined by analysis of TCGA and GEO public datasets. Immunohistochemistry and western blotting were utilized to evaluate the expression levels of SORL1 in OC tissues and cells that were sensitive or resistant to CDDP treatment. The in vitro effect of SORL1 on OC cisplatin resistance was proven by CCK-8 and cell apoptosis assays. The subcutaneous xenotransplantation model verified the in vivo significance of SORL1 in OC. Finally, the molecular mechanism by which SORL1 regulates OC cisplatin resistance was revealed by coimmunoprecipitation, gene set enrichment analysis and immunofluorescence analysis. This study demonstrated that SORL1 is closely related to CDDP resistance and predicts a poor prognosis in OC. In vivo xenograft experiments showed that SORL1 knockdown significantly enhanced the effect of CDDP on CDDP-resistant OC cells. Mechanistically, silencing of SORL1 inhibits the early endosomal antigen 1 (EEA1) pathway, which impedes the stability of ATP-binding cassette B subfamily member 1 (ABCB1), sensitizing CDDP-resistant OC cells to CDDP. The findings of this study suggest that targeting SORL1 may represent a promising therapeutic approach for overcoming CDDP resistance in OC.

Construction of Exosome SORL1 Detection Platform Based on 3D Porous Microfluidic Chip and its Application in Early Diagnosis of Colorectal Cancer.

Exosomes are promising new biomarkers for colorectal cancer (CRC) diagnosis, due to their rich biological fingerprints and high level of stability. However, the accurate detection of exosomes with specific surface receptors is limited to clinical application. Herein, an exosome enrichment platform on a 3D porous sponge microfluidic chip is constructed and the exosome capture efficiency of this chip is ≈90%. Also, deep mass spectrometry analysis followed by multi-level expression screenings revealed a CRC-specific exosome membrane protein (SORL1). A method of SORL1 detection by specific quantum dot labeling is further designed and the ensemble classification system is established by extracting features from 64-patched fluorescence images. Importantly, the area under the curve (AUC) using this system is 0.99, which is significantly higher (p < 0.001) than that using a conventional biomarker (carcinoembryonic antigen (CEA), AUC of 0.71). The above system showed similar diagnostic performance, dealing with early-stage CRC, young CRC, and CEA-negative CRC patients.

LRP4-IgG service line testing in seronegative myasthenia gravis and controls.

BACKGROUND: LRP4 is a post-synaptic membrane protein that promotes acetylcholine (AChR) clustering on the crest of post-synaptic neuromuscular folds. Autoantibodies against LRP4 are suggested to account for myasthenia gravis (MG) patients negative for antibodies to AChR. OBJECTIVES: To report a clinical experience with service-line LRP4-IgG cell-based testing in electrodiagnostically confirmed MG patients and controls. METHODS: We identified all Mayo patients undergoing MG evaluations with send out LRP4-IgG antibody testing by cell-based assay, having clinical-electrodiagnostic (EDX) testing. To be included, muscle acetylcholine receptor binding (AChR-Bi) and muscle-specific tyrosine kinase (MuSK) antibodies had to be absent prior to LRP4-IgG testing. Follow-up AChR-Bi antibody testing was reviewed. Also tested for LRP4-IgGs were 119 healthy subjects. RESULTS: Identified were 25 generalized MG, 24 ocular MG, and 55 patients initially considered to have MG prior to negative EDX testing. No seronegative patients with EDX confirmed MG had LRP4-IgG positivity but five non-MG patients did: Guillain-Barre syndrome with fatigue (N = 1); multiple cranial neuropathies (N = 1); functional neurologic disorders (N = 3). Of healthy subjects, 4% (5/119) were LRP4-IgG positive (N = 5) or had a borderline result (N = 1). Of MG patients with repeat AChR-Bi testing, 40% (10/25) seroconverted (5 with ocular MG and 5 with generalized MG) (median AChR IgG value: 0.34 nmol/L, range 0.2-20.9 nmol/L, median followup 26 months, range 2-72 months). CONCLUSION: Clinical review of LRP4-IgG commercial cell-based testing suggests lack of diagnostic utility in seronegative EDX-confirmed MG. The clinical utility of LRP4-IgG testing is not substantiated in service line testing. In contrast, repeat testing for AChR-Bi antibodies is shown clinically useful.

The VWF/LRP4/αVß3-axis represents a novel pathway regulating proliferation of human vascular smooth muscle cells.

AIMS: Von Willebrand factor (VWF) is a plasma glycoprotein involved in primary haemostasis, while also having additional roles beyond haemostasis namely in cancer, inflammation, angiogenesis, and potentially in vascular smooth muscle cell (VSMC) proliferation. Here, we addressed how VWF modulates VSMC proliferation and investigated the underlying molecular pathways and the in vivo pathophysiological relevance. METHODS AND RESULTS: VWF induced proliferation of human aortic VSMCs and also promoted VSMC migration. Treatment of cells with a siRNA against αv integrin or the RGT-peptide blocking αvß3 signalling abolished proliferation. However, VWF did not bind to αvß3 on VSMCs through its RGD-motif. Rather, we identified the VWF A2 domain as the region mediating binding to the cells. We hypothesized the involvement of a member of the LDL-related receptor protein (LRP) family due to their known ability to act as co-receptors. Using the universal LRP-inhibitor receptor-associated protein, we confirmed LRP-mediated VSMC proliferation. siRNA experiments and confocal fluorescence microscopy identified LRP4 as the VWF-counterreceptor on VSMCs. Also co-localization between αvß3 and LRP4 was observed via proximity ligation analysis and immuno-precipitation experiments. The pathophysiological relevance of our data was supported by VWF-deficient mice having significantly reduced hyperplasia in carotid artery ligation and artery femoral denudation models. In wild-type mice, infiltration of VWF in intimal regions enriched in proliferating VSMCs was found. Interestingly, also analysis of human atherosclerotic lesions showed abundant VWF accumulation in VSMC-proliferating rich intimal areas. CONCLUSION: VWF mediates VSMC proliferation through a mechanism involving A2 domain binding to the LRP4 receptor and integrin αvß3 signalling. Our findings provide new insights into the mechanisms that drive physiological repair and pathological hyperplasia of the arterial vessel wall. In addition, the VWF/LRP4-axis may represent a novel therapeutic target to modulate VSMC proliferation.

Circulating sLR11 levels predict severity of pulmonary hypertension due to left heart disease.

BACKGROUND: Heart failure is a severe condition often involving pulmonary hypertension (PH). Soluble low-density lipoprotein receptor with 11 ligand-binding repeats (sLR11) has been associated with pulmonary artery hypertension. We examined whether sLR11 correlates with PH in left heart disease and can be used as a predictive marker. METHOD: We retrospectively analyzed patients with severe mitral regurgitation who underwent right heart catheterization before surgery for valve replacement or valvuloplasty from November 2005 to October 2012 at Juntendo University. We measured sLR11 levels before right heart catheterization and analyzed correlations with pulmonary hemodynamics. We compared prognoses between a group with normal sLR11 (≤9.4 ng/ml) and a group with high sLR11 (>9.4 ng/ml). Follow-up was continued for 5 years, with end points of hospitalization due to HF and death due to cardiovascular disease. RESULTS: Among 34 patients who met the inclusion criteria, sLR11 correlated with mean pulmonary artery pressure (r = 0.54, p<0.001), transpulmonary pressure gradient (r = 0.42, p = 0.012), pulmonary vascular resistance (r = 0.36, p<0.05), and log brain natriuretic peptide (BNP). However, logBNP did not correlate with pulmonary vascular resistance (p = 0.6). Levels of sLR11 were significantly higher in the 10 patients with PH (14.4±4.3 ng/ml) than in patients without PH (9.9±3.9 ng/ml; p = 0.002). At 5 years, the event rate was higher in the high-sLR11 group than in the normal-sLR11 group. The high-sLR11 group showed 5 hospitalizations due to HF (25.0%) and 2 deaths (10.0%), whereas the normal-sLR11 group showed no hospitalizations or deaths. Analyses using receiver operating characteristic curves showed a higher area under the concentration-time curve (AUC) for sLR11 level (AUC = 0.85; 95% confidence interval (CI) = 0.72-0.98) than for BNP (AUC = 0.80, 95%CI = 0.62-0.99) in the diagnosis of PH in left heart disease. CONCLUSIONS: Concentration of sLR11 is associated with severity of PH and offers a strong predictor of severe mitral regurgitation in patients after surgery.

Connecting Cholesterol Efflux Factors to Lung Cancer Biology and Therapeutics.

Cholesterol is a foundational molecule of biology. There is a long-standing interest in understanding how cholesterol metabolism is intertwined with cancer biology. In this review, we focus on the known connections between lung cancer and molecules mediating cholesterol efflux. A major take-home lesson is that the roles of many cholesterol efflux factors remain underexplored. It is our hope that this article would motivate others to investigate how cholesterol efflux factors contribute to lung cancer biology.

Mechanism of disease and therapeutic rescue of Dok7 congenital myasthenia.

Congenital myasthenia (CM) is a devastating neuromuscular disease, and mutations in DOK7, an adaptor protein that is crucial for forming and maintaining neuromuscular synapses, are a major cause of CM1,2. The most common disease-causing mutation (DOK71124_1127 dup) truncates DOK7 and leads to the loss of two tyrosine residues that are phosphorylated and recruit CRK proteins, which are important for anchoring acetylcholine receptors at synapses. Here we describe a mouse model of this common form of CM (Dok7CM mice) and a mouse with point mutations in the two tyrosine residues (Dok72YF). We show that Dok7CM mice had severe deficits in neuromuscular synapse formation that caused neonatal lethality. Unexpectedly, these deficits were due to a severe deficiency in phosphorylation and activation of muscle-specific kinase (MUSK) rather than a deficiency in DOK7 tyrosine phosphorylation. We developed agonist antibodies against MUSK and show that these antibodies restored neuromuscular synapse formation and prevented neonatal lethality and late-onset disease in Dok7CM mice. These findings identify an unexpected cause for disease and a potential therapy for both DOK7 CM and other forms of CM caused by mutations in AGRIN, LRP4 or MUSK, and illustrate the potential of targeted therapy to rescue congenital lethality.

Coix lacryma-jobi Seed Oil Reduces Fat Accumulation in Nonalcoholic Fatty Liver Disease by Inhibiting the Activation of the p-AMPK/SePP1/apoER2 Pathway.

The lipid metabolism disorder is the key role of Nonalcoholic fatty liver disease (NAFLD). Selenoprotein P plays an important role in the pathological process of lipid accumulation. Coix lacryma-jboi seed oil (CLSO) is an active component extracted from Coix lacryma-jobi seed (CLS) which has been found to be effective of reducing blood fat and antioxidative. But the effect and mechanism of CLSO on NAFLD are not clear. The aim of this study was to explore the therapeutic effect and mechanism of CLSO in the treatment of NAFLD. Our result showed that CLSO decreased the liver/body weight ratio, lowered the total cholesterol (TC) and triacylglycerol (TG), and elevated the high density lipoprotein (HDL) in serum. CLSO reduced the lipid deposition in the liver of NAFLD rats. In addition, CLSO could bring down the abnormal expression of superoxide dismutase (SOD) and malondialdehyde (MDA). Moreover, CLSO significantly declined the liver apolipoprotein E (apoE), apolipoprotein E receptor (apoER) and selenoprotein P 1 (SePP1) expression. In vivo, CLSO decreased the lipid droplets and TG level, reduced the protein expression of SePP1, apoER, phosphor-adenosine 5'-monophosphate (AMP)-activated protein kinase (p-AMPK) in the cytoplasm of HepG2 cells induced by oleic acid and palmitic acid (OP). At the same time, lipid accumulation was observed in the Sepp1 high expression cells induced by endoplasmic reticulum (ER) activator tunicamycin (Tm). CLSO could identically reduce the protein expression of SePP1, apoER, p-AMPK in the cytoplasm of HepG2 cells induced by Tm. This result not only proved the CLSO had therapeutic effect on NAFLD, but also confirmed its mechanism associated with degrading the phosphorylation of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) which led to the decrease of the expression SePP1/apoER2 in order to reduce lipid accumulation. The study suggests CLSO has great medicinal value in treating NAFLD besides its edibility.

miR-30b-5p inhibits cancer progression and enhances cisplatin sensitivity in lung cancer through targeting LRP8.

Accumulated evidence has demonstrated that miRNAs are closely implicated in lung carcinogenesis. Herein, we explored the expression pattern of miR-30b-5p in lung cancer, and aimed to uncover miR-30b-5p roles in lung cancer progression and drug resistance. miR-30b-5p expression profiles in lung cancer tissues and the matched non-tumor tissues were determined by using qPCR. Cell viability, migration, invasion and in vivo tumorigenesis were determined by using the CCK-8, colony formation, wound healing, transwell chambers experiments and tumor xenograft models. RNA immunoprecipitation (RIP) and dual luciferase reporter experiments were applied to evaluate the relationship between miR-30b-5p and LRP8. The results demonstrated that miR-30b-5p showed a low expression profile in lung cancer tissues and cells, and closely linked to poor prognosis and malignant clinical process. Cell viability, migration, invasiveness and tumorigenesis were significantly weakened following miR-30b-5p overexpression in A549 and NCI-H1299 cells, while cell apoptosis rates were increased. In addition, miR-30b-5p was lowly expressed in A549/DDP (a cisplatin drug resistant cell line) as compared with A549 cells, and miR-30b-5p increased A549/DDP cell sensitivity to DDP. However, these above roles of miR-30b-5p were all significantly impaired following the overexpression of LRP8 which was overexpressed in lung cancer tissues. Collectively, this study demonstrated that miR-30b-5p functions as a tumor suppressor in lung cancer, and re-sensitizes lung cancer cells to DDP by targeting LRP8.

LDLRAD2 promotes pancreatic cancer progression through Akt/mTOR signaling pathway.

Low-density lipoprotein receptor class A domain containing 2 (LDLRAD2) acts as a protein-coding gene in a large number of human diseases. However, the potential roles and underlying mechanism in pancreatic cancer remains unclear. Therefore, this study was conducted to address this question. Herein, we found that the expression of LDLRAD2 was elevated in pancreatic cancer tissues and cell lines. LDLRAD2 knockdown inhibited pancreatic cancer cell proliferation, migration, and invasion in vitro. Besides, silencing LDLRAD2 impaired tumor growth and metastasis in vivo and up-regulated the E-Cadherin level, whereas down-regulated the expression of N-Cadherin and Vimentin levels, which indicating that LDLRAD2 knockdown suppresses EMT. Additionally, LDLRAD2 knockdown decreased the Warburg effect and glycolytic enzymes expression. Pathway scan assay and western blotting assay indicated that LDLRAD2 knockdown significantly down-regulated the expression of phosphorylation of Akt and phosphorylation of mTOR, which suggested that knockdown of LDLRAD2 inhibits Akt/mTOR signaling pathway. Taken together, these findings suggested that LDLRAD2 may be an oncogene in pancreatic cancer via modulating Akt/mTOR signaling pathway.

LRP4 promotes migration and invasion of gastric cancer under the regulation of microRNA-140-5p.

BACKGROUND: Low-density lipoprotein receptor-related protein 4 (LRP4) has been reported to be implicated in multiple types of cancers. However, the significance of LRP4 in gastric cancer (GC) remains poorly elucidated. Therefore, it's urgent to investigate the importance and underlying mechanisms of LRP4 in GC. OBJECTIVE: To investigate the clinical roles of LRP4 in GC. METHODS: The LRP4 mRNA and miR-140-5p was measured by qRT-PCR. The protein expression was determined Western blot. Kaplan-Meier survival curves and Cox proportional hazard regression models were performed to evaluate prognosis. RESULTS: We demonstrated that LRP4 mRNA and protein was up-regulated in GC tissues for the first time. Its high expression was significantly correlated with malignant clinical features including TNM stage and lymph-node metastasis and poor prognosis for GC patients. LRP4 promotes migration, invasion and epithelial-mesenchymal transition (EMT) progress of GC cells. Mechanically, LRP4 regulated PI3K/AKT in GC cells. AKT inhibitors reversed the effects of LRP4. Finally, LRP4 was regulated by miR-140-5p in GC. CONCLUSIONS: Our findings showed that LRP4 has an important function in GC progression and promotes GC migration, invasion and EMT by regulating PI3K/AKT under regulation of miR-140-5p, providing a potential therapeutic target for GC.

Genome-scale CRISPR activation screening identifies a role of LRP8 in Sorafenib resistance in Hepatocellular carcinoma.

Sorafenib may provide survival benefits for patients with advanced hepatocellular carcinoma. However, tumor cells can display primary or secondary resistance to Sorafenib. To identify genes capable of conveying Sorafenib resistance, we performed a genome-wide CRISPR transcriptional activation library (SAM) in human Huh7 cells. We identified that a group of sgRNAs were significantly enriched in Sorafenib resistant Huh7 cells, which indicated that these sgRNAs up-regulated their target genes and induced resistance. We finally identified LRP8 as a key gene that can drive HCC cell to acquire sorafenib resistance. All three sgRNAs targeting LRP8 were identified in Sorafenib resistant Huh7 cells with high copy. We also showed that sorafenib-acquired resistant Huh7 cells have much higher LRP8 expression level than parental Huh7 cells. We proved that overexpression of LRP8 in HCC cell lines activated ß-catenin and significantly promoted its resistance to Sorafenib. We further showed that overexpression of LRP8 reduced the apoptosis level of HCC cell lines. To summary, genome-scale CRISPR activation screening identifies a role of LRP8 in Sorafenib resistance in Hepatocellular carcinoma.

Apolipoprotein E2 modulates cell cycle function to promote proliferation in pancreatic cancer cells via regulation of the c-Myc-p21Waf1 signalling pathway.

Apolipoprotein E2 (ApoE2) is reportedly critical for cell proliferation and survival, and has been identified as a potential tumour-associated marker in many kinds of cancer. However, studies of the function and mechanisms of ApoE2 in pancreatic cancer proliferation and development are rare. In this study, we performed an analysis to determine the modulatory effects of ApoE2-LRP8 (lipoprotein receptor-related protein 8) pathway on cell cycle and cell proliferation, and explored its mechanisms in pancreatic cancer. High expression levels of ApoE2-LRP8/c-Myc were detected in tumour tissues and cell lines by immunohistochemistry and Western blotting. It was also shown that ApoE2-LRP8 induced phosphorylation of ERK1/2 to activate c-Myc and contribute to cell-cycle-related protein expression. ApoE2 conditions induced c-Myc binding to target gene sequences in the p21Waf1 promoter, resulting in decreased transcription. ERK/c-Myc contributes to the promotion of the expression levels of cyclin D1, cdc2, and cyclin B1, and reduces p21Waf1 activity, thereby promoting cell cycle distribution. We demonstrated the function of ApoE2-LRP8 in the activation of the ERK-c-Myc-p21Waf1 signalling cascade and the modulation of G1/S and G2/M transition, indicating ApoE2-LRP8's important role in the cancer cell proliferation. ApoE2 could serve as a diagnostic marker and chemotherapeutic target in pancreatic cancer.

5-Caffeoylquinic Acid Ameliorates Cognitive Decline and Reduces Aß Deposition by Modulating Aß Clearance Pathways in APP/PS2 Transgenic Mice.

The accumulation of amyloid ß (Aß) in the brain is a major pathological feature of Alzheimer's disease (AD). In our previous study, we demonstrated that coffee polyphenols (CPP) prevent cognitive dysfunction and Aß deposition in the brain of an APP/PS2 transgenic mouse AD model. The underlying mechanisms, however, remain to be elucidated. Here, we investigated the effects of the chronic administration of 5-caffeoylquinic acid (5-CQA), the most abundant component of CPP, on cognitive dysfunction in APP/PS2 mice to identify the role of CPP in Aß elimination. Relative to the untreated controls, the mice fed a 5-CQA-supplemented diet showed significant improvements in their cognitive function assessed by Y-maze and novel object recognition tests. Histochemical analysis revealed that 5-CQA substantially reduced Aß plaque formation and neuronal loss in the hippocampi. Moreover, 5-CQA upregulated the gene encoding low-density lipoprotein receptor-related protein 1, an Aß efflux receptor, and normalized the perivascular localization of aquaporin 4, which facilitates Aß clearance along the paravascular pathway. These results suggest that 5-CQA reduces Aß deposition in the brain by modulating the Aß clearance pathways and ameliorating cognitive decline and neuronal loss in APP/PS2 mice. Thus, 5-CQA may be effective in preventing cognitive dysfunction in AD.

LDLRAD2 overexpression predicts poor prognosis and promotes metastasis by activating Wnt/ß-catenin/EMT signaling cascade in gastric cancer.

The therapeutic strategies for advanced gastric cancer (GC) remain unsatisfying and limited. Therefore, it is still imperative to fully elucidate the mechanisms underlying GC aggressive progression. The prognostic value and biological functions of low density lipoprotein receptor class A domain containing protein 2 (LDLRAD2) in GC have never been studied yet. We found that LDLRAD2 expression was significantly upregulated in GC and closely correlated with poor prognosis in GC patients. Functionally, LDLRAD2 promoted epithelial-mesenchymal transition, migration and invasion, and metastasis of GC cells. Mechanistically, LDLRAD2 interacted with and inhibited Axin1 from binding to cytoplasmic ß-catenin, which facilitated the nuclear translocation of ß-catenin, thereby activating Wnt/ß-catenin pathway. Inhibition of ß-catenin activity markedly abolished LDLRAD2-induced migration, invasion and metastasis. Together, these results suggested that LDLRAD2 contributed to invasion and metastasis of GC through activating Wnt/ß-catenin pathway. LDLRAD2/ Wnt/ß-catenin axis may be a potential therapeutic target for GC treatment.

LRP receptors in chondrocytes are modulated by simulated microgravity and cyclic hydrostatic pressure.

Mechanical loading is essential for the maintenance of musculoskeletal homeostasis. Cartilage has been demonstrated to be highly mechanoresponsive, but the mechanisms by which chondrocytes respond to mechanical stimuli are not clearly understood. The goal of the study was to determine how LRP4, LRP5, and LRP6 within canonical Wnt-signaling are regulated in simulated microgravity and cyclic hydrostatic pressure, and to investigate the potential role of LRP 4/5/6 in cartilage degeneration. Rat chondrosacroma cell (RCS) pellets were stimulated using either cyclic hydrostatic pressure (1Hz, 7.5 MPa, 4hr/day) or simulated microgravity in a rotating wall vessel (RWV) bioreactor (11RPM, 24hr/day). LRP4/5/6 mRNA expression was assessed by RT-qPCR and LRP5 protein expression was determined by fluorescent immunostaining. To further evaluate our in vitro findings in vivo, mice were subjected to hindlimb suspension for 14 days and the femoral heads stained for LRP5 expression. We found that, in vitro, LRP4/5/6 mRNA expression is modulated in a time-dependent manner by mechanical stimulation. Additionally, LRP5 protein expression is upregulated in response to both simulated microgravity and cyclic hydrostatic pressure. LRP5 is also upregulated in vivo in the articular cartilage of hindlimb suspended mice. This is the first study to examine how LRP4/5/6, critical receptors within musculoskeletal biology, respond to mechanical stimulation. Further elucidation of this mechanism could provide significant clinical benefit for the identification of pharmaceutical targets for the maintenance of cartilage health.

Myasthenia Gravis: Pathogenic Effects of Autoantibodies on Neuromuscular Architecture.

Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction (NMJ). Autoantibodies target key molecules at the NMJ, such as the nicotinic acetylcholine receptor (AChR), muscle-specific kinase (MuSK), and low-density lipoprotein receptor-related protein 4 (Lrp4), that lead by a range of different pathogenic mechanisms to altered tissue architecture and reduced densities or functionality of AChRs, reduced neuromuscular transmission, and therefore a severe fatigable skeletal muscle weakness. In this review, we give an overview of the history and clinical aspects of MG, with a focus on the structure and function of myasthenic autoantigens at the NMJ and how they are affected by the autoantibodies' pathogenic mechanisms. Furthermore, we give a short overview of the cells that are implicated in the production of the autoantibodies and briefly discuss diagnostic challenges and treatment strategies.