HMGB1/TLR4 signaling pathway enhances abdominal aortic aneurysm progression in mice by upregulating necroptosis.

OBJECTIVE AND DESIGN: The age-associated increases in aseptic inflammation and necroptosis are closely related to the emergence of various age-associated diseases. METHODS: In this study, the role of HMGB1/TLR4-induced necroptosis in abdominal aortic aneurysm (AAA) formation was investigated. First, the levels of sterile inflammatory mediators (HMGB1, TLR4) and necroptosis markers were measured in the abdominal aortas of young and old C57BL/6JNifdc mice. We observed that sterile inflammatory mediators and necroptosis markers were greatly increased in the abdominal aortas of old mice. Then, angiotensin II (Ang II)-induced AAA model in APOE-/- mice was used in this study. Mice AAA models were treated with the RIP1 inhibitor necrostatin-1 (Nec-1) or the TLR4 inhibitor TAK-242, respectively. RESULTS: We found that HMGB1, TLR4, and necroptosis markers were elevated in old mice compared with those in young mice. Same elevation was also found in the development of AAA in APOE-/- mice. In addition, the necroptosis inhibitor Nec-1 alleviated Ang II-induced AAA development while downregulating the expression of HMGB1/TLR4. After blocking TLR4 with TAK-242, the expression of necroptosis markers decreased significantly, and the progression of AAA was also alleviated in APOE-/- mice. CONCLUSIONS: Our results indicated that HMGB1/TLR4-mediated necroptosis enhances AAA development in the Ang II-induced AAA model in APOE-/- mice and that TLR4 might be a potential therapeutic target for AAA management.

An animal model of EPO-induced abdominal aortic aneurysm in WT and Apoe-/- mice.

Abdominal aortic aneurysm (AAA) is a potentially fatal vascular disease, but the underlying mechanisms remain obscure. Here, we provide a protocol using erythropoietin (EPO) to induce the formation of AAA in both wild-type (WT) and apolipoprotein E (Apoe-/-) mice. We describe the dose, manner, and timing of EPO administration. We also detail mice dissection, aorta isolation, and histological analysis. The animal model of EPO-induced AAA provides a useful tool for exploring the mechanism of AAA in experimental studies. For complete details on the use and execution of this protocol, please refer to Zhang et al. (2021).1.

Knockdown of Bcl-3 alleviates psoriasis and dyslipidemia comorbidity by regulating Akt pathway.

BACKGROUND: Psoriasis is considered as an inflammatory skin disease accompanied by dyslipidemia comorbidity. B-cell leukemia-3 (Bcl-3) belongs to IκB (inhibitor of nuclear factor kappa B [NF-κB]) family, and regulates inflammatory response through associating with NF-κB. The role of Bcl-3 in psoriasis was investigated in this study. METHODS: Apolipoprotein E (ApoE)-deficient mice were treated with imiquimod to induce psoriasis and dyslipidemia. Mice were injected intradermally in the back with lentiviral particles encoding Bcl-3 small hairpin RNA (shRNA). Hematoxylin and eosin were used to detect pathological characteristics. The blood lipid levels were determined by automatic biochemical analyzer, and inflammation was assessed by enzyme-linked-immunosorbent serologic assay and real-time quantitative reverse transcription polymerase chain reaction. RESULTS: Bcl-3 was elevated in imiquimod-induced ApoE-deficient mice. Injection with lentiviral particles encoding Bcl-3 shRNA reduced Psoriasis area and severity index (PASI) score in ApoE-deficient psoriatic mice. Knockdown of Bcl-3 also ameliorated imiquimod-induced psoriasiform skin lesions in ApoE-deficient mice. Moreover, loss of Bcl-3 enhanced expression of loricrin, an epidermal barrier protein, reduced expression of proliferating cell nuclear antigen (PCNA) and lectin-like oxidized LDL (oxLDL) receptor-1 (LOX-1) in imiquimod-induced ApoE-deficient mice. The enhanced levels of blood lipid in ApoE-deficient mice were attenuated by silencing of Bcl-3 with increase of high-density lipoprotein, and reduction of total cholesterol, triglycerides, and low-density lipoprotein cholesterol. Knockdown of Bcl-3 attenuated imiquimod-induced decrease of transforming growth factor beta (TGF-ß), and increase of Interleukin (IL)-17A, IL-23, IL-6, and tumor necrosis factor-α (TNF-α) in ApoE-deficient mice. Protein expression of phospho-Akt (p-Akt) and p-GSK3ß in ApoE-deficient psoriatic mice was decreased by silencing of Bcl-3. CONCLUSION: Loss of Bcl-3 exerted anti-inflammatory effect on psoriasis and dyslipidemia comorbidity through inactivation of Akt/GSK3ß pathway.

The molecular mechanism of Ang II induced-AAA models based on proteomics analysis in ApoE-/- and CD57BL/6J mice.

Apolipoprotein knockout (ApoE-/-) and CD57BL/6J mouse models of angiotensin II (Ang II)-induced abdominal aortic aneurysm (AAA) are commonly used in AAA research. However, the similarities and differences in the molecular mechanisms of AAA in these two genotypes have not been reported. In our study, we analyzed proteomics data from ApoE-/- and CD57BL/6J mouse models of Ang II-induced AAA and control mice by LC-MS/MS. Gene set enrichment analysis (GSEA) of differentially abundance proteins (DAPs) in the ApoE-/- or CD57BL/6J mouse groups was performed in R software, and infiltration of immune cells in groups was assessed. DAP that showed the same trend in abundance in ApoE-/- and CD57BL/6J mice (S-DAP) were identified and subjected to GO enrichment, KEGG pathway, and connectivity map (CMap) analyses. The protein-protein interaction (PPI) network of the S-DAP was drawn, the key S-DAP were identified by MCODE, and the transcription factors (TFs) of crucial S-DAP were predicted by iRegulon in Cytoscape. Male ApoE-/- and CD57BL/6J mouse models of Ang II-induced AAA are commonly used in AAA research, and extracellular matrix organization is associated with AAA in both of these models. However, there are some differences between the mechanisms underlying AAA in these two genotypes, and these differences need to be considered when studying AAA and selecting models. SIGNIFICANCE: Our research provided the first insight into the similarity and differential mechanisms of Ang II infused AAA models using ApoE-/- and CD57BL/6J mice. This study might provide the some advises for the selection of Ang II infused AAA models for further AAA researches.

APOE region molecular signatures of Alzheimer's disease across races/ethnicities.

The role of even the strongest genetic risk factor for Alzheimer's disease (AD), the apolipoprotein E (APOE) ε4 allele, in its etiology remains poorly understood. We examined molecular signatures of AD defined as differences in linkage disequilibrium patterns between AD-affected and -unaffected whites (2673/16,246), Hispanics (392/867), and African Americans (285/1789), separately. We focused on 29 polymorphisms from 5 genes in the APOE region emphasizing beneficial and adverse effects of the APOE ε2- and ε4-coding single-nucleotide polymorphisms, respectively, and the differences in the linkage disequilibrium structures involving these alleles between AD-affected and -unaffected subjects. Susceptibility to AD is likely the result of complex interactions of the ε2 and ε4 alleles with other polymorphisms in the APOE region, and these interactions differ across races/ethnicities corroborating differences in the adverse and beneficial effects of the ε4 and ε2 alleles. Our findings support complex race/ethnicity-specific haplotypes promoting and protecting against AD in this region. They contribute to better understanding of polygenic and resilient mechanisms, which can explain why even homozygous ε4 carriers may not develop AD.

Arabidopsis thaliana extracts optimized for polyphenols production as potential therapeutics for the APOE-modulated neuroinflammation characteristic of Alzheimer's disease in vitro.

Although the cause of Alzheimer's disease (AD) is unknown, glial-induced neuroinflammation is an early symptom. Familial AD is caused by increases in amyloid-beta (Aß) peptide, particularly soluble oligomeric (oAß), considered a proximal neurotoxin and neuroinflammatory stimuli. APOE4, a naturally occurring genotype of APOE, is the greatest genetic risk factor for AD; increasing risk up to 12-fold compared to APOE3 and APOE2. oAß-induced neuroinflammation is greater with APOE4 compared to APOE3 and APOE2. As sinapates and flavonoids have anti-inflammatory properties, a protocol was developed for optimizing polyphenol production in seedlings of Arabidopsis thaliana (A. thaliana). Three mutants (cop1, prn1, xpf3) were identified, and the extracts treated with liver microsomes to mimic physiological metabolism, with HPLC and MS performed on the resulting metabolites for peak identification. These extracts were used to treat primary glial cells isolated from human APOE-targeted-replacement (APOE-TR) and APOE-knock-out (KO) mice, with neuroinflammation induced by lipopolysaccharide (LPS) or oAß. The dose-response data for TNFα secretion demonstrate the followed the order: APOE-KO > APOE4 > APOE3 > APOE2, with xpf3 the most effective anti-neuroinflammatory across APOE genotypes. Thus, the plant-based approach described herein may be particularly valuable in treating the APOE4-induced neuroinflammatory component of AD risk.

Polimorfismo -219 G/T en el gen APOE en relación con los niveles de colesterol y la enfermedad aterosclerótica en Argentina / APOE -219G/T Polymorphism related to serum lipid levels in atherosclerotic patients from Argentina

El alelo ε4 del gen APOE se asocia con riesgo aumentado de Enfermedad Cardiovascular Aterosclerótica (ECA) y con mayores concentraciones de colesterol total (CT) y de LDL (c-LDL) en plasma; sin embargo, algunos estudios no reprodujeron esos resultados. Esta controversia señala que otros factores, genéticos y/o ambientales podrían actuar sobre estas asociaciones. Variaciones cuantitativas en los niveles de expresión del gen originadas por polimorfismos en el promotor, como el -219G/T, podrían tener un rol como factor de riesgo de la enfermedad. Previamente los autores del presente trabajo hemos reportado la asociación entre el alelo ε4 y la presencia de lesiones ateroscleróticas en varones. En este trabajo se investiga si hay asociación entre el polimorfismo APOE -219G/T, la ECA y los niveles de lípidos en plasma. Se estudiaron 380 muestras de ADN de pacientes con estudios angiográficos realizados, provenientes de la zona sur de la provincia de Buenos Aires. El análisis con regresiones logísticas mostró diferencias no significativas en las distribuciones del alelo T y del alelo G entre casos y controles, aún después de estratificar por sexo y por edad. Con regresiones lineales se observó que: hay diferencias no significativas entre los niveles de CT y c-LDL y la presencia/ausencia del alelo T, pero el alelo G se asoció con valores más elevados de CT (p=0,001) y de c-LDL (p=0,020) en varones. Entre mujeres no hubo diferencias significativas. Estos resultados señalan que el alelo G del polimorfismo -219 del gen APOE se asocia con valores mayores de CT y LDL-c en varones, pero este polimorfismo no actuaría como un factor de riesgo de ECA en la población Argentina.

APOE ε4 allele is associated with increased risk for Coronary Artery Disease and higher concentrations of total-cholesterol and low-density-lipoprotein-cholesterol; however, some studies could not reproduce these results. This fact suggests that other genetic or environmental factors are acting on these associations. Quantitative variations of gene expression, conferred by polymorphisms in the promoter area, as -219G/T, could play also a role as a risk factor for CAD. Since, in a previous study, we found an association between the APOE ε4 allele and atherosclerotic lesions in males of our population, we investigated now whether the APOE promoter polymorphism -219 G/T is also associated with the presence of atherosclerotic lesions and plasma lipid levels. Genotypes were obtained from 380 DNA samples from patients undergoing an angiography study. Logistic regression analysis showed no significant associations between T allele, or G allele, and the presence of atherosclerotic lesions. Lineal regression analysis showed association between G allele and higher TC (p=0.002) and LDL-c (p=0.022) levels. After stratified by sex: TC (p=0.001) and LDL-c (p=0.020) for males, females showed no significant differences. For cases and controls groups, the allele G has still been associated with higher levels of TC (p=0.007, p= 0.048 respectively). No associations for T allele were observed. We conclude that G allele of polymorphism -219 on the promoter of APOE gene is associated with higher TC and LDL-c levels in males, but this polymorphism is not acting as a risk factor of CAD in our population.

La apolipoproteina E: el polimorfismo genetico y su relacion con los cambios metabolicos, los habitos alimenticios y el origen etnico / Apolipoprotein E: its relationship with differents forms of genetic expression and effect of etnic origin and nutritional habits

La apolipoproteína E (Apo E) es una proteína plasmática constituyente de las lipoproteínas, que tiene como función mantener la estructura y regular el metabolismo de varias de ellas. Los tres alelos más comunes del gen de Apo E son e2, e3 y e4, los cuales producen tres isoformas de la proteína, llamadas E2, E3 y E4. Estos tres alelos diferentes son heredados en forma codominante dando como resultado seis genotipos: E2/2, E3/2, E3/3, E3/4, E4/4, E4/E2. El genotipo E3/E3 es el normal, con una frecuencia poblacional de 77 por ciento. Se ha estimado que 60 por ciento de la variación plasmática del colesterol está determinada genéticamente; el polimorfismo de Apo E corresponde a 14 por ciento de esas variaciones genéticas. La deficiencia de Apo E causa hipercolesterolemia severa. Genotipos específicos han sido implicados en el desarrollo de aterosclerosis, de enfermedad coronaria, de hiperlipoproteinemia tipo III (HLP tipo III), de enfermedad cerebrovascular y de formas familiares y esporádicas de enfermedad de Alzheimer. Esta revisión muestra diferentes aspectos bioquímicos y genéticos de la apolipoproteína E, así como la relación de las diferentes formas de expresión genética de esta proteína con los cambios metabólicos de las lipoproteínas y con el origen étnico y los hábitos alimenticios

APOE epsilon4 and low cholesterol as risks for depression in a biracial elderly community sample.

OBJECTIVE: The epsilon4 allele of apolipoprotein (APOE) is known to be associated with a number of adverse health outcomes, yet the association of the allele with depression has not been conclusively determined. The authors explored the hypothesis that the epsilon4 allele is a risk factor for depression among older persons with a low cholesterol level (a known risk factor for depression). METHODS: A biracial community sample of 2,550 older African Americans and Whites in North Carolina was genotyped for APOE, tested for cholesterol, and evaluated for depression at both baseline and 4-year follow-up. RESULTS: No relationship was found between the epsilon4 allele and depression or low cholesterol and depression in either cross-sectional or longitudinal analyses. The interaction of the epsilon4 allele and cholesterol was also not associated with depression in controlled analyses. Female gender, less education, being unmarried, and cognitive impairment were associated with depression in cross-sectional controlled analyses; only cognitive impairment was associated with depression in longitudinal analyses. CONCLUSION: Despite the association of the epsilon4 allele with a number of adverse health outcomes, as well as the association between depression and cholesterol in previous studies, no association was found between epsilon4 and low cholesterol or depression in cross-sectional and longitudinal analyses. The interaction of epsilon4 and cholesterol was not associated with depression.

The clinical epidemiology of Alzheimer's disease.

Alzheimer's disease is a more common and malignant illness than was appreciated just 2 decades ago. In addition to being a major cause of mortality, it is costly and uniquely distressing for patients and their families. All indications are that the problem will grow as elderly populations expand. Fatalism regarding AD is premature, however. Much has been learned about this disease in only a few years, and it is hoped that this rate of discovery can be maintained or even accelerated in the future.