Chronic inflammation has been associated with numerous diseases, and
many old people suffer from chronic inflammatory illnesses; however, the
connections between age and inflammation are still obscure.
Aging is marked by an overall decline of tissue and cellular functions.
At the cellular level, it is accompanied with damages to DNA, RNA, and
impairments of protein functions. Organisms can detect these damages and
elicit innate immune responses to remove aged, dying or dead cells, and
cell debris from tissues. However, as the cells of innate immunity age,
their reduced energy production may hinder the clearance processes,
which require energy, thus, the persistence of this debris in tissues,
resulting in subsequent inflammatory responses. Cytokines accumulated
during inflammation could further deteriorate local tissues and
accelerate the aging process.
Benayoun et al. \cite{Benayoun_2019} used machine
learning that is capable of data-training, self-improvement, and
prediction to investigate epigenomic (three histone marks) and
transcriptomic landscapes in mice during the aging process and generated
by far the largest datasets, using multiple tissues such as
heart, liver, cerebellum, olfactory bulb, and primary culture of neural
stem cells from young, middle-aged, and old mice. The researchers
determined epigenomic states that could predict transcriptional changes
at specific genomic loci during aging. They found that, in all examined
tissues, the interferon response pathway was robustly activated, perhaps
to detect DNA damages and the expression of retrovirus-like transposons,
and that multiple innate immune pathways were also upregulated
significantly. These results strongly supported the conclusion that
inflammation is a commonly shared hallmark for vertebrate aging tissues.
If we can reduce or prevent the inflammation process, aged tissues may
be rejuvenated and prolonged for their normal functions. These
transcription factors provide potential targets for pharmaceutical
development and therapeutic strategies for healthy aging.
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