Research Article: Transcriptome analysis reveals immune-related gene expression changes with age in giant panda (Ailuropoda melanoleuca) blood

Date Published: January 15, 2019

Publisher: Impact Journals

Author(s): Lianming Du, Qin Liu, Fujun Shen, Zhenxin Fan, Rong Hou, Bisong Yue, Xiuyue Zhang.

http://doi.org/10.18632/aging.101747

Abstract

The giant panda (Ailuropoda melanoleuca), an endangered species endemic to western China, has long been threatened with extinction that is exacerbated by highly contagious and fatal diseases. Aging is the most well-defined risk factor for diseases and is associated with a decline in immune function leading to increased susceptibility to infection and reduced response to vaccination. Therefore, this study aimed to determine which genes and pathways show differential expression with age in blood tissues. We obtained 210 differentially expressed genes by RNA-seq, including 146 up-regulated and 64 down-regulated genes in old pandas (18-21yrs) compared to young pandas (2-6yrs). We identified ISG15, STAT1, IRF7 and DDX58 as the hub genes in the protein-protein interaction network. All of these genes were up-regulated with age and played important roles in response to pathogen invasion. Functional enrichment analysis indicated that up-regulated genes were mainly involved in innate immune response, while the down-regulated genes were mainly related to B cell activation. These may suggest that the innate immunity is relatively well preserved to compensate for the decline in the adaptive immune function. In conclusion, our findings will provide a foundation for future studies on the molecular mechanisms underlying immune changes associated with ageing.

Partial Text

The giant panda (Ailuropoda melanoleuca), an endangered species endemic to western China, has long been threatened with extinction due to human population expansion and habitat destruction [1, 2]. Recent research has shown that giant pandas are well adapted to a specialized bamboo diet via enigmatic gut microbiota and low energy expenditure [3–5]. Contrary to previous studies, the latest genome sequencing and resequencing and genome-wide genetic studies have demonstrated that the giant panda has a relatively high genetic diversity [6–8]. Over the years, extensive research has been conducted on genes of the major histocompatibility complex (MHC) in giant pandas and shown that DRB and DQA genes have low diversity but remain positive selection [9–11]. However, most of these studies focused on the adaptations and genetic diversity of giant pandas and little is known about the gene expression of immune-related genes.

In a previous study, we have characterized giant panda blood transcriptome and identified 15 immune pathways where more than 70% of the total known genes were mapped by assembled transcripts [30]. In the present study, we still applied the widely used RNA-seq approach to highlight significant DEGs in blood between young and old giant pandas. The previous work has proved that age had a broad impact on gene expression levels, whereas sex had very minimal effects on gene expression patterns [26]. Therefore, it is appropriate to investigate age-related changes in giant panda by sequencing the blood transcriptome. To the best of our knowledge, this is the first study to assess the impact of age on immune-related gene expression.

 

Source:

http://doi.org/10.18632/aging.101747

 

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