Thread by @microbeminded2

Important paper 👉 A team in Tokyo took RNA-seq data from the Genomic-#Tissue Expression Project: a public resource created to study tissue-specific gene expression/regulation from 54 tissue types collected from 1000+ healthy individuals at autopsy: bmcbiol.biomedcentral.com/articles/10.11…

2/ They successfully identified 39 viral species in at least one tissue (tissue types included #brain, pituitary, esophagus, thyroid, #heart, breast, lung, kidney, adrenal gland, prostate, #nerve, adipose tissue, blood vessel, ovary, uterus etc)

3/ Viruses identified in the various tissue samples included EBV, HSV-1, Varicella, CMV, HHV6-A/B, HHV-7, HCV, HPV, adeno-associated virus...and 16 RNA #viruses including Respiratory syncytial virus (RSV), Parainfluenza Virus 3..

4/...and interestingly Human coronavirus 229-E (found in #brain, thyroid, heart, lung, kidney, stomach, testes tissue, skin + blood (yet another study indicating coronaviruses seem capable of persistence!?)

5/ What do the findings mean? For one thing the team states: “We found that the human #virome includes several viruses ‘hidden’ by expression/replication in tissues inside the human body without being abundant in the blood.”

6/ But the tissues were collected from HEALTHY people. That gets to 2nd part of the study. The team also characterized how certain #viruses they identified in tissue associated with human gene expression + #immune activity/homeostasis

7/ As a general trend, gene expression/immune changes associated with viral presence in a tissue were associated with components of the immune response known to control #infection or keep #pathogens “in check”

8/ For example, genes associated with “type 1 interferon signaling pathway”, “defense response to #virus” and “viral process” were highly upregulated in Hepatitis C virus #liver tissue samples

9/ What that suggests to me is: 1) healthy humans can harbor both DNA/RNA viruses in their tissues 2) These viruses may not contribute to acute/chronic #disease processes if the immune system successfully controls their activity

10/ However, (and this is me talking now and not the paper!): what might happen to these same people if their immune response is weakened and/or dysregulated??

11/ It’s likely that the tissue-associated viruses may then change their activity + gene expression to contribute to conditions ranging from #cancers, to #Alzheimer’s to diabetes to #MECFS in some cases

12/ That is also a huge trend to consider with #LongCovid 👉 Can #COVID-19 dysregulate the immune response in a manner that allows viruses already persisting in tissue to better drive a broad range of chronic symptoms? #longhauler