Role of KCa3.1 Channels in Macrophage Polarization and Its Relevance in Atherosclerotic Plaque Instability

Objective—

Emerging evidence indicates that proinflammatory macrophage polarization imbalance plays a key role in atherosclerotic plaque progression and instability. The calcium-activated potassium channel KCa3.1 is critically involved in macrophage activation and function. However, the role of KCa3.1 in macrophage polarization is unknown. This study investigates the potential role of KCa3.1 in transcriptional regulation in macrophage polarization and its relationship to plaque instability.

Approach and Results—

Human monocytes were differentiated into macrophages using macrophage colony-stimulating factor. Macrophages were then polarized into proinflammatory M1 cells by interferon-γ and lipopolysaccharide and into alternative M2 macrophages by interleukin-4. A model for plaque instability was induced by combined partial ligation of the left renal artery and left common carotid artery in apolipoprotein E knockout mice. Significant upregulation of KCa3.1 expression was observed during the differentiation of human monocytes into macrophages. Blocking KCa3.1 significantly reduced the expression of proinflammatory genes during macrophages polarization. Further mechanistic studies indicated that blocking KCa3.1 inhibited macrophage differentiation toward the M1 phenotype by downregulating signal transducer and activator of transcription-1 phosphorylation. In animal models, KCa3.1 blockade therapy strikingly reduced the incidence of plaque rupture and luminal thrombus in carotid arteries, decreased the expression of markers associated with M1 macrophage polarization, and enhanced the expression of M2 markers within atherosclerotic lesions.

Conclusions—

These results suggest that blocking KCa3.1 suppresses plaque instability in advanced stages of atherosclerosis by inhibiting macrophage polarization toward an M1 phenotype.

Halogenated flame retardants in bobcats from the midwestern United States

In response to the restrictions of polybrominated diphenyl ether (PBDE) flame retardants in various consumer products, alternative halogenated flame retardants have been subjected to increased use. Compared to aquatic ecosystems, relatively little information is available on the contamination of alternative flame retardants in terrestrial ecosystems, especially with regards to mammalian wildlife. In this study we used a top terrestrial carnivore, the bobcat (Lynx rufus), as a unique biomonitoring species for assessing flame retardant contamination in the Midwestern United States (U.S.) terrestrial ecosystems. Concentrations of ∑PBDEs (including all detectable PBDE congeners) ranged from 8.3 to 1920 ng/g lipid weight (median: 50.3 ng/g lw) in livers from 44 bobcats collected during 2013-2014 in Illinois. Among a variety of alternative flame retardants screened, Dechloranes (including anti- and syn-Dechlorane Plus and Dechlorane-602, 603, and 604), tetrabromo-o-chlorotoluene (TBCT), and hexabromocyclododecane (HBCD) were also frequently detected, with median concentrations of 28.7, 5.2, and 11.8 ng/g lw, respectively. Dechlorane analogue compositions in bobcats were different from what has been reported in other studies, suggesting species- or analogue-dependent bioaccumulation, biomagnification, or metabolism of Dechlorane chemicals in different food webs. Our findings, along with previously reported food web models, suggest Dechloranes may possess substantial bioaccumulation and biomagnification potencies in terrestrial mammalian food webs. Thus, attention should be given to these highly bioavailable flame retardants in future environmental biomonitoring and risk assessments in a post-PBDE era.

Early age at menarche and gestational diabetes mellitus risk: Results from the Healthy Baby Cohort study

AIM

Early age at menarche has been reported to increase type 2 diabetes risk, but little is known of its impact on gestational diabetes mellitus (GDM) risk. The aim of this study was to examine the association between age at menarche and plasma glucose levels as well as GDM risk.

METHODS

A total of 6900 pregnant women from the Healthy Baby Cohort Study were included in our analysis. Age at menarche was self-reported and categorized into five groups (9-11, 12, 13, 14 and 15-18 years of age). GDM was diagnosed using the International Association of Diabetes and Pregnancy Study Groups criteria. Comparisons of plasma glucose levels according to age at menarche categories were performed using analysis of covariance. Logistic regression models were used to estimate the association between age at menarche and GDM risk.

RESULTS

Of our 6900 participants, 1015 (14.7%) were diagnosed with GDM. Mean age at menarche was 13.1±1.2 years. Early age at menarche (9-11 years) was associated with higher fasting, 1-h and 2-h plasma glucose levels (all P<0.05) compared with menarche at age 13 years. Furthermore, early age at menarche was linked to increased GDM risk after adjusting for potential confounders (OR: 1.41, 95% CI: 1.06-1.87).

CONCLUSION

Early age at menarche is an independent risk factor for GDM and, as such, may help to identify women at higher GDM risk who would benefit from early preventative strategies.

Cryptotanshinone potentiates the antitumor effects of doxorubicin on gastric cancer cells via inhibition of STAT3 activity

Objective To investigate the synergistic effects of cryptotanshinone (CPT) and doxorubicin (DOXO) on induction of apoptosis in human gastric cancer cells and the mechanisms. Methods Cell proliferation and apoptosis were detected using the CCK8 assay and AnnexinV/PI staining, respectively. Western blotting was used to determine the levels and phosphorylation of proteins encoded by STAT3-regulated genes and the cleaved forms of caspases and PARP. Results CPT significantly potentiated the antiproliferative effect of DOXO in gastric cancer cell lines. CPT combined with DOXO induced apoptosis and cleavage of caspases-3,-7,-9 as well as PARP. CPT or a STAT3 siRNA significantly suppressed constitutive and IL-6-induced phosphorylation of STAT3 Tyr705, decreasing the levels of proteins encoded by STAT3-target genes (Bcl-xL, Mcl-1, survivin, and XIAP). Conclusions CPT enhanced the anticancer activity of DOXO in gastric cancer cells via STAT3 inactivation and suppression STAT3-regulated antiapoptotic gene expression, indicating that DOXO combined with CPT may serve as effective therapy for gastric cancer.

Radiolabeled novel mAb 4G1 for immunoSPECT imaging of EGFRvIII expression in preclinical glioblastoma xenografts

Epidermal growth factor receptor mutant III (EGFRvIII) is exclusively expressed in tumors, such as glioblastoma, breast cancer and hepatocellular carcinoma, but never in normal organs. Increasing evidence suggests that EGFRvIII has clinical significance in glioblastoma prognosis due to its enhanced tumorigenicity and chemo/radio resistance, thus the development of an imaging approach to early detect EGFRvIII expression with high specificity is urgently needed. To illustrate this point, we developed a novel anti-EGFRvIII monoclonal antibody 4G1 through mouse immunization, cell fusion and hybridoma screening and then confirmed its specificity and affinity by a serial of assays. Following biodistribution and small animal single-photon emission computed tomography (SPECT/CT) imaging of 125I-4G1 in EGFRvIII positive/negative tumor-bearing mice were performed and evaluated to verify the tumor accumulation of this radiotracer. The biodistribution indicated that 125I-4G1 showed prominent tumor accumulation at 24 h post-injection, which reached maximums of 11.20 ± 0.75% ID/g and 13.98 ± 0.57% ID/g in F98npEGFRvIII and U87vIII xenografts, respectively. In contrast, 125I-4G1 had lower tumor accumulation in F98npEGFR and U87MG xenografts. Small animal SPECT/CT imaging revealed that 125I-4G1 had a higher tumor uptake in EGFRvIII-positive tumors than that in EGFRvIII-negative tumors. This study demonstrates that radiolabeled 4G1 can serve as a valid probe for the imaging of EGFRvIII expression, and would be valuable into the clinical translation for the diagnosis, prognosis, guiding therapy, and therapeutic efficacy evaluation of tumors.

Sparse Canonical Correlation Analysis via Truncated ℓ1-norm with Application to Brain Imaging Genetics

Discovering bi-multivariate associations between genetic markers and neuroimaging quantitative traits is a major task in brain imaging genetics. Sparse Canonical Correlation Analysis (SCCA) is a popular technique in this area for its powerful capability in identifying bi-multivariate relationships coupled with feature selection. The existing SCCA methods impose either the ℓ₁-norm or its variants. The ℓ₀-norm is more desirable, which however remains unexplored since the ℓ₀-norm minimization is NP-hard. In this paper, we impose the truncated ℓ₁-norm to improve the performance of the ℓ₁-norm based SCCA methods. Besides, we propose two efficient optimization algorithms and prove their convergence. The experimental results, compared with two benchmark methods, show that our method identifies better and meaningful canonical loading patterns in both simulated and real imaging genetic analyse.

Novel genetic loci associated with hippocampal volume

The hippocampal formation is a brain structure integrally involved in episodic memory, spatial navigation, cognition and stress responsiveness. Structural abnormalities in hippocampal volume and shape are found in several common neuropsychiatric disorders. To identify the genetic underpinnings of hippocampal structure here we perform a genome-wide association study (GWAS) of 33,536 individuals and discover six independent loci significantly associated with hippocampal volume, four of them novel. Of the novel loci, three lie within genes (ASTN2, DPP4 and MAST4) and one is found 200 kb upstream of SHH. A hippocampal subfield analysis shows that a locus within the MSRB3 gene shows evidence of a localized effect along the dentate gyrus, subiculum, CA1 and fissure. Further, we show that genetic variants associated with decreased hippocampal volume are also associated with increased risk for Alzheimer's disease (rg=-0.155). Our findings suggest novel biological pathways through which human genetic variation influences hippocampal volume and risk for neuropsychiatric illness.

Key Genes in Stomach Adenocarcinoma Identified via Network Analysis of RNA-Seq Data

RNA-seq data of stomach adenocarcinoma (STAD) were analyzed to identify critical genes in STAD. Meanwhile, relevant small molecule drugs, transcription factors (TFs) and microRNAs (miRNAs) were also investigated. Gene expression data of STAD were downloaded from The Cancer Genome Atlas (TCGA). Differential analysis was performed with package edgeR. Relationships with correlation coefficient > 0.6 were retained in the gene co-expression network. Functional enrichment analysis was performed for the genes in the network with DAVID and KOBASS 2.0. Modules were identified using Cytoscape. Relevant small molecules drugs, transcription factors (TFs) and microRNAs (miRNAs) were revealed by using CMAP and WebGestalt databases. A total of 520 DEGs were identified between 285 STAD samples and 33 normal controls, including 244 up-regulated and 276 down-regulated genes. A gene co-expression network containing 53 DEGs and 338 edges was constructed, the genes of which were significantly enriched in focal adhesion, ECM-receptor interaction and vascular smooth muscle contraction pathways. Three modules were identified from the gene co-expression network and they were associated with skeletal system development, inflammatory response and positive regulation of cellular process, respectively. A total of 20 drugs, 9 TFs and 6 miRNAs were acquired that may regulate the DEGs. NFAT-COL1A1/ANXA1, HSF2-FOS, SREBP-IL1RN and miR-26-COL5A2 regulation axes may be important mechanisms for STAD.

Transcriptome-Guided Imaging Genetic Analysis via a Novel Sparse CCA Algorithm

Imaging genetics is an emerging field that studies the influence of genetic variation on brain structure and function. The major task is to examine the association between genetic markers such as single nucleotide polymorphisms (SNPs) and quantitative traits (QTs) extracted from neuroimaging data. Sparse canonical correlation analysis (SCCA) is a bi-multivariate technique used in imaging genetics to identify complex multi-SNP-multi-QT associations. In imaging genetics, genes associated with a phenotype should at least expressed in the phenotypical region. We study the association between the genotype and amyloid imaging data and propose a transcriptome-guided SCCA framework that incorporates the gene expression information into the SCCA criterion. An alternating optimization method is used to solve the formulated problem. Although the problem is not biconcave, a closed-form solution has been found for each subproblem. The results on real data show that using the gene expression data to guide the feature selection facilities the detection of genetic markers that are not only associated with the identified QTs, but also highly expressed there.

Systems Health: A Transition from Disease Management Toward Health Promotion

To date, most of the chronic diseases such as cancer, cardiovascular disease, and diabetes, are the leading cause of death. Current strategies toward disease treatment, e.g., risk prediction and target therapy, still have limitations for precision medicine due to the dynamic and complex nature of health. Interactions among genetics, lifestyle, and surrounding environments have nonnegligible effects on disease evolution. Thus a transition in health-care area is urgently needed to address the hysteresis of diagnosis and stabilize the increasing health-care costs. In this chapter, we explored new insights in the field of health promotion and introduced the integration of systems theories with health science and clinical practice. On the basis of systems biology and systems medicine, a novel concept called "systems health" was comprehensively advocated. Two types of bioinformatics models, i.e., causal loop diagram and quantitative model, were selected as examples for further illumination. Translational applications of these models in systems health were sequentially discussed. Moreover, we highlighted the bridging of ancient and modern views toward health and put forward a proposition for citizen science and citizen empowerment in health promotion.

Protective Effects of Luteolin on Lipopolysaccharide-Induced Acute Renal Injury in Mice

Background

Sepsis can cause serious acute kidney injury in bacterium-infected patients, especially in intensive care patients. Luteolin, a bioactive flavonoid, has renal protection and anti-inflammatory effects. This study aimed to investigate the effect and underlying mechanism of luteolin in attenuating lipopolysaccharide (LPS)-induced renal injury.

Material/Methods

ICR mice were treated with LPS (25 mg/kg) with or without luteolin pre-treatment (40 mg/kg for three days). The renal function, histological changes, degree of oxidative stress, and tubular apoptosis in these mice were examined. The effects of luteolin on LPS-induced expression of renal tumor necrosis factor-α (TNF-α), NF-κB, MCP-1, ICAM-1, and cleaved caspase-3 were evaluated.

Results

LPS resulted in rapid renal damage of mice, increased level of blood urea nitrogen (BUN), and serum creatinine (Scr), tubular necrosis, and increased oxidative stress, whereas luteolin pre-treatment could attenuate this renal damage and improve the renal functions significantly. Treatment with LPS increased TNF-α, NF-κB, IL-1β, cleaved caspase-3, MCP-1, and ICAM-1 expression, while these disturbed expressions were reversed by luteolin pre-treatment.

Conclusions

These results indicate that luteolin ameliorates LPS-mediated nephrotoxicity via improving renal oxidant status, decreasing NF-κB activation and inflammatory and apoptosis factors, and then disturbing the expression of apoptosis-related proteins.

Integrative Analysis of Sex-Specific microRNA Networks Following Stress in Mouse Nucleus Accumbens

Adult women are twice as likely as men to suffer from affective and anxiety disorders, although the mechanisms underlying heightened female stress susceptibility are incompletely understood. Recent findings in mouse Nucleus Accumbens (NAc) suggest a role for DNA methylation-driven sex differences in genome-wide transcriptional profiles. However, the role of another epigenetic process-microRNA (miR) regulation-has yet to be explored. We exposed male and female mice to Subchronic Variable Stress (SCVS), a stress paradigm that produces depression-like behavior in female, but not male, mice, and performed next generation mRNA and miR sequencing on NAc tissue. We applied a combination of differential expression, miR-mRNA network and functional enrichment analyses to characterize the transcriptional and post-transcriptional landscape of sex differences in NAc stress response. We find that male and female mice exhibit largely non-overlapping miR and mRNA profiles following SCVS. The two sexes also show enrichment of different molecular pathways and functions. Collectively, our results suggest that males and females mount fundamentally different transcriptional and post-transcriptional responses to SCVS and engage sex-specific molecular processes following stress. These findings have implications for the pathophysiology and treatment of stress-related disorders in women.

Knowledge-Guided Bioinformatics Model for Identifying Autism Spectrum Disorder Diagnostic MicroRNA Biomarkers

Autism spectrum disorder (ASD) is a severe neurodevelopmental disease with a high incidence and effective biomarkers are urgently needed for its diagnosis. A few previous studies have reported the detection of miRNA biomarkers for autism diagnosis, especially those based on bioinformatics approaches. In this study, we developed a knowledge-guided bioinformatics model for identifying autism miRNA biomarkers. We downloaded gene expression microarray data from the GEO Database and extracted genes with expression levels that differed in ASD and the controls. We then constructed an autism-specific miRNA-mRNA network and inferred candidate autism biomarker miRNAs based on their regulatory modes and functions. We defined a novel parameter called the autism gene percentage as autism-specific knowledge to further facilitate the identification of autism-specific biomarker miRNAs. Finally, 11 miRNAs were screened as putative autism biomarkers, where eight miRNAs (72.7%) were significantly dysregulated in ASD samples according to previous reports. Functional enrichment results indicated that the targets of the identified miRNAs were enriched in autism-associated pathways, such as Wnt signaling (in KEGG and IPA), cell cycle (in KEGG), and glioblastoma multiforme signaling (in IPA), thereby supporting the predictive power of our model.

Decreased frequencies and impaired functions of the CD31+ subpopulation in Treg cells associated with decreased FoxP3 expression and enhanced Treg cell defects in patients with coronary heart disease

Coronary heart disease (CHD) is one of the most common types of organ lesions caused by atherosclerosis, in which CD4⁺ CD25⁺ forkhead box protein 3 (FoxP3⁺ ) regulatory T cells (T_reg ) play an atheroprotective role. However, T_reg cell numbers are decreased and their functions are impaired in atherosclerosis; the underlying mechanisms remain unclear. CD31 plays an important part in T cell response and contributes to maintaining T cell tolerance. The immunomodulatory effects of CD31 are also implicated in atherosclerosis. In this study, we found that decreased frequencies of the CD31⁺ subpopulation in T_reg cells (CD31⁺ Tr cells) correlated positively with decreased FoxP3 expression in CHD patients. Cell culture in vitro demonstrated CD31⁺ Tr cells maintaining stable FoxP3 expression after activation and exhibited enhanced proliferation and immunosuppression compared with the CD31^- subpopulation in T_reg cells (CD31^- Tr cells). We also confirmed impaired secretion of transforming growth factor (TGF)-β1 and interleukin (IL)-10 in CD31⁺ Tr cells of CHD patients. Further analysis revealed reduced phospho-SHP2 (associated with CD31 activation) and phospho-signal transducer and activator of transcription-5 (STAT-5) (associated with FoxP3 transcription) levels in CD31⁺ Tr cells of CHD patients, suggesting that decreased FoxP3 expression in CD31⁺ Tr cells might be because of attenuated SHP2 and STAT-5 activation. These data indicate that decreased frequencies and impaired functions of the CD31⁺ Tr subpopulation associated with decreased FoxP3 expression give rise, at least in part, to T_reg cell defects in CHD patients. Our findings emphasize the important role of the CD31⁺ Tr subpopulation in maintaining T_reg cell normal function and may provide a novel explanation for impaired immunoregulation of T_reg cells in CHD.

miR-958 inhibits Toll signaling and Drosomycin expression via direct targeting of Toll and Dif in Drosophila melanogaster

Drosophila melanogaster is widely used as a model system to study innate immunity and signaling pathways related to innate immunity, including the Toll signaling pathway. Although this pathway is well studied, the precise mechanisms of posttranscriptional regulation of key components of the Toll signaling pathway by microRNAs (miRNAs) remain obscure. In this study, we used an in silico strategy in combination with the Gal80^ts-Gal4 driver system to identify microRNA-958 (miR-958) as a candidate Toll pathway regulating miRNA in Drosophila We report that overexpression of miR-958 significantly reduces the expression of Drosomycin, a key antimicrobial peptide involved in Toll signaling and the innate immune response. We further demonstrate in vitro and in vivo that miR-958 targets the Toll and Dif genes, key components of the Toll signaling pathway, to negatively regulate Drosomycin expression. In addition, a miR-958 sponge rescued the expression of Toll and Dif, resulting in increased expression of Drosomycin. These results, not only revealed a novel function and modulation pattern of miR-958, but also provided a new insight into the underlying molecular mechanisms of Toll signaling in regulation of innate immunity.

Comprehensive mapping of 5-hydroxymethylcytosine epigenetic dynamics in axon regeneration

In contrast to central nervous system neurons, dorsal root ganglia (DRG) neurons can switch to a regenerative state after peripheral axotomy. In a screen for chromatin regulators of the regenerative responses in this conditioning lesion paradigm, we identified Tet methylcytosine dioxygenase 3 (Tet3) as upregulated in DRG neurons, along with increased 5-hydroxymethylcytosine (5hmC). We generated genome-wide 5hmC maps in adult DRG, which revealed that peripheral and central axotomy (leading to no regenerative effect) triggered differential 5hmC changes that are associated with distinct signaling pathways. 5hmC was altered in a large set of regeneration-associated genes (RAGs), including well-known RAGs, such as Atf3, Bdnf, and Smad1, that regulate axon growth potential of DRG neurons, thus supporting its role for RAG regulation. Our analyses also predicted HIF-1, STAT, and IRF as potential transcription factors that may collaborate with Tet3 for 5hmC modifications. Intriguingly, central axotomy resulted in widespread 5hmC modifications that had little overlap with those of peripheral axotomy, thus potentially constituting a roadblock for regeneration. Our study revealed 5hmC dynamics as a previously unrecognized epigenetic mechanism underlying the divergent responses after axonal injury.

Low-dose developmental exposure to bisphenol A alters the femoral bone geometry in wistar rats

BACKGROUND

Bisphenol A (BPA) is a chemical produced in large volumes for use in manufacturing of consumer products and industrial applications, and an endocrine disruptor known to affect several hormonal systems. Bone produces hormones and is additionally a sensitive hormone target tissue, and is thus potentially sensitive to low doses of endocrine disruptors such as BPA, especially during development.

METHODS

110 pregnant Wistar rats were gavaged with 0; 25 μg; 250 μg; 5000 μg or 50,000 μg BPA/kg bodyweight (bw)/day from gestational day 7 until weaning at postnatal day 22. The three-month-old offspring were sacrificed and right femurs collected for length measurements, geometrical measurements by peripheral quantitative computed tomography (pQCT), as well as for analyses of biomechanical properties using the three-point-bending method.

RESULTS

The femur was elongated in female offspring of dams exposed to 25 or 5000 μg BPA/kg bw/day (1.8% and 2.1%, respectively), and increased cortical thickness (4.7%) was observed in male offspring of dams exposed to 25 μg BPA/kg bw/day, compared to controls (p < 0.005). The biomechanical properties of the bone were not significantly altered.

CONCLUSIONS

In utero and lactational exposure to the lowest BPA dose used in this study altered femoral geometry in both male and female offspring. This was observed at 25 μg BPA/kg bw/day, a dose lower than the Human Equivalent Dose (HED) applied by EFSA to set a temporary TDI (609 μg BPA/kg bw/day), and far lower than the No-Observed-Adverse-Effect-Level (NOAEL) (5000 μg BPA/kg bw/day) on which the US FDA TDI is based.

Novel genetic loci underlying human intracranial volume identified through genome-wide association

Intracranial volume reflects the maximally attained brain size during development, and remains stable with loss of tissue in late life. It is highly heritable, but the underlying genes remain largely undetermined. In a genome-wide association study of 32,438 adults, we discovered five previously unknown loci for intracranial volume and confirmed two known signals. Four of the loci were also associated with adult human stature, but these remained associated with intracranial volume after adjusting for height. We found a high genetic correlation with child head circumference (ρgenetic = 0.748), which indicates a similar genetic background and allowed us to identify four additional loci through meta-analysis (Ncombined = 37,345). Variants for intracranial volume were also related to childhood and adult cognitive function, and Parkinson's disease, and were enriched near genes involved in growth pathways, including PI3K-AKT signaling. These findings identify the biological underpinnings of intracranial volume and their link to physiological and pathological traits.