Age-related Transcriptome Changes Research Articles

Knockout of Hsp70 Genes Modulates Age-Related Transcriptomic Changes in Leg Muscles and Reduces the Locomotion Speed and Lifespan of Drosophila melanogaster

Knockout of Hsp70 Genes Modulates Age-Related Transcriptomic Changes in Leg Muscles and Reduces the Locomotion Speed and Lifespan of Drosophila melanogaster

(221) Anatomical Transcriptome Atlas of the Male Mouse Reproductive System During Aging

Abstract Introduction The elderly males undergo degenerative fertility and testicular endocrine function that jeopardize the reproductive health and well-being. However, the mechanisms underlying reproductive aging are unclear. Objective This study aims to investigate the phenotypes and transcriptomes of seven regions of the male mouse reproductive tract: the testis, efferent ductules, initial segment, caput, corpus and cauda epididymidis, and vas deferens, in adult (3 months) and aged (21 months) mice. Methods Quantitative PCR, immunohistochemistry, immunofluorescent staining, and enzyme-linked immunosorbent assay were performed for the analysis of gene expression in mice, human tissues, and semen samples. Aged male mice showed both systematic and reproductive changes, and remarkable histological changes were detected in the testis and proximal epididymis. Transcriptomes of the male reproductive tract were mapped, and a series of region-specific genes were identified and validated in mouse and/or human tissues, including Protamine 1 (Prm2), ADAM metallopeptidase domain 28 (Adam28), Ribonuclease A family member 13 (Rnase13), WAP four-disulfide core domain 13 (Wfdc13), and Wfdc9. Meanwhile, age-related transcriptome changes of different regions of the male reproductive tract were characterized. Results Notably, increased immune response was functionally related to the male reproductive aging, especially the T cell activation. An immune response-associated factor, phospholipase A2 group IID (Pla2g2d), was identified as a potential biomarker for reproductive aging in mice. And the PLA2G2D level in human seminal plasma surged at approximately 35 years of age. Furthermore, we highlighted Protein tyrosine phosphatase receptor type C (Ptprc), Lymphocyte protein tyrosine kinase (Lck), Microtubule associated protein tau (Mapt), and Interferon induced protein with tetratricopeptide repeats 3 (Ifit3) as critical molecules in the aging of initial segment, caput, caput, and cauda epididymidis, respectively. Conclusions This study provides an RNA-seq resource for the male reproductive system during aging in mice, and is expected to improve our understanding of male reproductive aging and infertility. Disclosure No.

RNAseq transcriptome profiling reveals activation of immune responses and disrupted circadian patterns in the cerebral white matter of aged mice (P4-6.003)

<h3>Objective:</h3> We aim to map transcriptome profiles of mouse corpus callosum using young (5-month-old) and aged (24-month-old) mice. <h3>Background:</h3> Aging is a risk factor for several neurological diseases. Although the approach of transcriptome profiling by RNAseq has been used to examine age-related changes in RNA expression levels in the brain, how aging affects the transcriptome of cerebral white matter is still mostly unknown. <h3>Design/Methods:</h3> All experimental procedures followed NIH guidelines and were approved by the MGH Institutional Animal Care and Use Committee. Male C57BL6J mice (N=12 for the young; N=12 for the aged) were used. Mice were sacrificed at either ZT1, ZT7, ZT13, or ZT19 to obtain corpus callosum samples (N=3/group). Then, RNA samples were prepared and used for bulk RNAseq. <h3>Results:</h3> Regardless of the time zones for sample preparation, inflammatory responses were activated in aged mice. Especially, genes that are related to complement classical pathways were significantly upregulated in the aged corpus callosum compared to the young group. On the other hand, there were several upregulated genes in the young group. The most upregulated gene in the young corpus callosum was tenascin C, which is a major extracellular matrix glycoprotein, and the pathway analysis showed that the pathways of glial cell development (GO:0021782) and regulation of nervous system development (GO:0051960) were highly enriched in the list of differentially expressed genes (DEGs). Interestingly, the circadian patterns of some genes were disrupted in the aged corpus callosum. In addition, the number of DEGs between young and aged mice was more significant in ZT1 (inactive phase for mice) compared to ZT13 (active phase), suggesting that age-related differences in gene expression patterns may depend on circadian time points. <h3>Conclusions:</h3> Our current study provides a novel dataset for white-matter-specific transcriptome profiles in mice. Our data would help us understand the mechanism of age-related transcriptome changes in cerebral white matter. <b>Disclosure:</b> Dr. Ishikawa has nothing to disclose. Dr. Hamanaka has nothing to disclose. Dr. Mandeville has nothing to disclose. Mrs. Guo has nothing to disclose. Dr. Li has nothing to disclose. Akihiro Shindo has nothing to disclose. Eng Lo has nothing to disclose. Ken Arai has nothing to disclose.

Anatomical Transcriptome Atlas of the Male Mouse Reproductive System During Aging.

The elderly males undergo degenerative fertility and testicular endocrine function that jeopardize the reproductive health and well-being. However, the mechanisms underlying reproductive aging are unclear. Here, we tried to address this by investigating the phenotypes and transcriptomes of seven regions of the male mouse reproductive tract: the testis, efferent ductules, initial segment, caput, corpus and cauda epididymidis, and vas deferens, in adult (3 months) and aged (21 months) mice. Quantitative PCR, immunohistochemistry, immunofluorescent staining, and enzyme-linked immunosorbent assay were performed for the analysis of gene expression in mice, human tissues, and semen samples. Aged male mice showed both systematic and reproductive changes, and remarkable histological changes were detected in the testis and proximal epididymis. Transcriptomes of the male reproductive tract were mapped, and a series of region-specific genes were identified and validated in mouse and/or human tissues, including Protamine 1 (Prm2), ADAM metallopeptidase domain 28 (Adam28), Ribonuclease A family member 13 (Rnase13), WAP four-disulfide core domain 13 (Wfdc13), and Wfdc9. Meanwhile, age-related transcriptome changes of different regions of the male reproductive tract were characterized. Notably, increased immune response was functionally related to the male reproductive aging, especially the T cell activation. An immune response-associated factor, phospholipase A2 group IID (Pla2g2d), was identified as a potential biomarker for reproductive aging in mice. And the PLA2G2D level in human seminal plasma surged at approximately 35 years of age. Furthermore, we highlighted Protein tyrosine phosphatase receptor type C (Ptprc), Lymphocyte protein tyrosine kinase (Lck), Microtubule associated protein tau (Mapt), and Interferon induced protein with tetratricopeptide repeats 3 (Ifit3) as critical molecules in the aging of initial segment, caput, caput, and cauda epididymidis, respectively. This study provides an RNA-seq resource for the male reproductive system during aging in mice, and is expected to improve our understanding of male reproductive aging and infertility.

Age-related transcriptome changes in melanoma patients with tumor-positive sentinel lymph nodes.

Age is an important factor for determining the outcome of melanoma patients. Sentinel lymph node (SLN) status is also a strong predictor of survival for melanoma. Paradoxically, older melanoma patients have a lower incidence of SLN metastasis but a higher mortality rate when compared with their younger counterparts. The mechanisms that underlie this phenomenon remain unknown. This study uses three independent datasets of RNA samples from patients with melanoma metastatic to the SLN to identify age-related transcriptome changes in SLNs and their association with outcome. Microarray was applied to the first dataset of 97 melanoma patients. NanoString was performed in the second dataset to identify the specific immune genes and pathways that are associated with recurrence in younger versus older patients. qRT-PCR analysis was used in the third dataset of 36 samples to validate the differentially expressed genes (DEGs) from microarray and NanoString. These analyses show that FOS, NR4A, and ITGB1 genes were significantly higher in older melanoma patients with positive SLNs. IRAK3- and Wnt10b-related genes are the major pathways associated with recurrent melanoma in younger and older patients with tumor-positive SLNs, respectively. This study aims to elucidate age-related differences in SLNs in the presence of nodal metastasis.

Genome-wide Profiling Identifies DNA Methylation Signatures of Aging in Rod Photoreceptors Associated with Alterations in Energy Metabolism

Aging-associated functional decline is accompanied by alterations in the epigenome. To explore DNA modifications that could influence visual function with age, we perform whole-genome bisulfite sequencing of purified mouse rod photoreceptors at four ages and identify 2,054 differentially methylated regions (DMRs). We detect many DMRs during early stages of aging and in rod regulatory regions, and some of these cluster at chromosomal hotspots, especially on chromosome 10, which includes a longevity interactome. Integration of methylome to age-related transcriptome changes, chromatin signatures,and first-order protein-protein interactions uncover an enrichment of DMRs in altered pathwaysthat are associated with rod function, aging, and energy metabolism. In concordance, we detect reduced basal mitochondrial respiration and increased fatty acid dependency with retinal age in exvivo assays. Our study reveals age-dependent genomic and chromatin features susceptible to DNA methylation changes in rod photoreceptors and identifies a link between DNA methylation and energy metabolism in aging.

Age-related transcriptome changes in Sox2+ supporting cells in the mouse cochlea

BackgroundInner ear supporting cells (SCs) in the neonatal mouse cochlea are a potential source for hair cell (HC) regeneration, but several studies have shown that the regeneration ability of SCs decreases dramatically as mice age and that lost HCs cannot be regenerated in adult mice. To better understand how SCs might be better used to regenerate HCs, it is important to understand how the gene expression profile changes in SCs at different ages.MethodsHere, we used Sox2GFP/+ mice to isolate the Sox2+ SCs at postnatal day (P)3, P7, P14, and P30 via flow cytometry. Next, we used RNA-seq to determine the transcriptome expression profiles of P3, P7, P14, and P30 SCs. To further analyze the relationships between these age-related and differentially expressed genes in Sox2+ SCs, we performed gene ontology (GO) analysis.ResultsConsistent with previous reports, we also found that the proliferation and HC regeneration ability of isolated Sox2+ SCs significantly decreased as mice aged. We identified numerous genes that are enriched and differentially expressed in Sox2+ SCs at four different postnatal ages, including cell cycle genes, signaling pathway genes, and transcription factors that might be involved in regulating the proliferation and HC differentiation ability of SCs. We thus present a set of genes that might regulate the proliferation and HC regeneration ability of SCs, and these might serve as potential new therapeutic targets for HC regeneration.ConclusionsIn our research, we found several genes that might play an important role in regulating the proliferation and HC regeneration ability of SCs. These datasets are expected to serve as a resource to provide potential new therapeutic targets for regulating the ability of SCs to regenerate HCs in postnatal mammals.

Early-life DNA methylation profiles are indicative of age-related transcriptome changes

BackgroundAlterations to cellular and molecular programs with brain aging result in cognitive impairment and susceptibility to neurodegenerative disease. Changes in DNA methylation patterns, an epigenetic modification required for various CNS functions are observed with brain aging and can be prevented by anti-aging interventions, but the relationship of altered methylation to gene expression is poorly understood.ResultsPaired analysis of the hippocampal methylome and transcriptome with aging of male and female mice demonstrates that age-related differences in methylation and gene expression are anti-correlated within gene bodies and enhancers. Altered promoter methylation with aging was found to be generally un-related to altered gene expression. A more striking relationship was found between methylation levels at young age and differential gene expression with aging. Highly methylated gene bodies and promoters in early life were associated with age-related increases in gene expression even in the absence of significant methylation changes with aging. As well, low levels of methylation in early life were correlated to decreased expression with aging. This relationship was also observed in genes altered in two mouse Alzheimer’s models.ConclusionDNA methylation patterns established in youth, in combination with other epigenetic marks, were able to accurately predict changes in transcript trajectories with aging. These findings are consistent with the developmental origins of disease hypothesis and indicate that epigenetic variability in early life may explain differences in aging trajectories and age-related disease.

Synchronized age-related gene expression changes across multiple tissues in human and the link to complex diseases.

Aging is one of the most important biological processes and is a known risk factor for many age-related diseases in human. Studying age-related transcriptomic changes in tissues across the whole body can provide valuable information for a holistic understanding of this fundamental process. In this work, we catalogue age-related gene expression changes in nine tissues from nearly two hundred individuals collected by the Genotype-Tissue Expression (GTEx) project. In general, we find the aging gene expression signatures are very tissue specific. However, enrichment for some well-known aging components such as mitochondria biology is observed in many tissues. Different levels of cross-tissue synchronization of age-related gene expression changes are observed, and some essential tissues (e.g., heart and lung) show much stronger “co-aging” than other tissues based on a principal component analysis. The aging gene signatures and complex disease genes show a complex overlapping pattern and only in some cases, we see that they are significantly overlapped in the tissues affected by the corresponding diseases. In summary, our analyses provide novel insights to the co-regulation of age-related gene expression in multiple tissues; it also presents a tissue-specific view of the link between aging and age-related diseases.

R-α-lipoic acid does not reverse hepatic inflammation of aging, but lowers lipid anabolism, while accentuating circadian rhythm transcript profiles

To determine the effects of age and lipoic acid supplementation on hepatic gene expression, we fed young (3 mo) and old (24 mo) male Fischer 344 rats a diet with or without 0.2% (wt/wt) R-α-lipoic acid (LA) for 2 wk. Total RNA isolated from liver tissue was analyzed by Affymetrix microarray to examine changes in transcriptional profiles. Results showed elevated proinflammatory gene expression in the aging liver and evidence for increased immune cell activation and tissue remodeling, together representing 45% of the age-related transcriptome changes. In addition, age-related increases in transcripts of genes related to fatty acid, triglyceride, and cholesterol synthesis, including acetyl-CoA carboxylase-β (Acacb) and fatty acid synthase (Fasn), were observed. Supplementation of old animals with LA did not reverse the necroinflammatory phenotype but, intriguingly, altered the expression of genes governing circadian rhythm. Most notably, Arntl, Npas2, and Per changed in a coordinated manner with respect to rhythmic transcription. LA further caused a decrease in transcripts of several bile acid and lipid synthesis genes, including Acacb and Fasn, which are regulated by first-order clock transcription factors. Similar effects of LA supplementation on bile acid and lipid synthesis genes were observed in young animals. Transcript changes of lipid metabolism genes were corroborated by a decrease in FASN and ACC protein levels. We conclude that advanced age is associated with a necroinflammatory phenotype and increased lipid synthesis, while chronic LA supplementation influences hepatic genes associated with lipid and energy metabolism and circadian rhythm, regardless of age.

Introduction

<h3>Summary</h3> One inevitable consequence of aging is the gradual deterioration of physical function and exercise capacity, driven in part by the adverse effect of age on muscle tissue. Our primary purpose was to determine the relationship between patterns of gene expression in skeletal muscle and this loss of physical function. We hypothesized that some genes changing expression with age would correlate with functional decline, or conversely with preservation of function. Male C57BL/6 mice (6-months old, 6m, 24-months, 24m, and 28+-months, 28m; all n=8) were tested for physical ability using a <b>c</b>omprehensive <b>f</b>unctional <b>a</b>ssessment <b>b</b>attery (CFAB). CFAB is a composite scoring system comprised of five functional tests: rotarod (overall motor function), grip strength (fore-limb strength), inverted cling (4-limb strength/endurance), voluntary wheel running (activity rate/volitional exercise), and treadmill (endurance). We then extracted total RNA from the tibialis anterior muscle, analyzed with Next Generation Sequencing RNAseq to determine differential gene expression during aging, and compared these changes to physical function. Aging resulted in gene expression differences &gt;│1.0│ log2 fold change (multiple comparison adjusted p&lt;0.05) in <b>219</b> genes in the 24m and in <b>6587</b> genes in the 28m. Linear regression with CFAB determined <b>253</b> differentially expressed genes strongly associated (R&gt;0.70) with functional status in the 28m, and <b>22</b> genes in the 24m. We conclude that specific age-related transcriptomic changes are associated with declines in physical function, providing mechanistic clues. Future work will establish the underlying cellular mechanisms and the physiological relevance of these genes to age-related loss of physical function. <h3>Graphical Abstract</h3> RNA sequencing of skeletal muscle from young and old mice were compared to physical function status obtained by performing a comprehensive functional assessment battery of tests. Between adulthood (6-months) and older age (28-months), 6707 genes were differentially expressed with 253 of these genes being significantly associated with physical function. Specific age-related changes to the skeletal muscle transcriptome are associated with a decline in physical function.