2022 Joint Usage and Research Report
Title of Research Project
Institution
ApplicantElucidation of the role of SKIV2L in innate immunity.
University of Chittagong, Bangladesh.

Job title

Associate Professorand Name

Sunanda Baidya

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Under35

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Institution
Research

Job titlecollaboratorsand Name

(Please add lines as

Institution

appropriate)

Job titleand Name

Host researcher at IGM

Professor Akinori Takaoka

Purpose of the Research Project

It has been reported previously that mutation in SKIV2L, a(approx. 250 words)

component of RNA exosome is responsible for a rare congenital
bowel disorder trichohepatoenteric syndrome (THES) [Fabre A,et al, Am J Hum Genet. 2012; 90:689-692]. SKIV2L is a negative
regulator of RIG-I-like receptors, which trigger innate immune
responses against viral infection, and loss of SKIV2L function can
result in type I interferon overproduction. Moreover, humanpatients with SKIV2L deficiency have a potent IFN signature in
their peripheral blood cells [Eckard SC, et al, Nat Immunol.
2014;15:839-845]. However, the role of SKIV2L in constitutive
weak interferon signal is not fully understand yet. Thus, thepurpose of the study is to investigate the role of SKIV2L ininnate immunity.

Development of the Research

To elucidate the role of SKIV2L in innate immunity we had

Project and Results

successfully generated HEK293T SKIV2L KO cells and found(approx.. 850 words)

elevated IFNβ and IFNλ mRNA expressions in KO cells than wild

*Enter the number of web

type HEK 293T cells by qRT-PCR. Next, we transfect SKIV2L

meetings.

plasmid DNA through Lipofactamine 2000 to the SKIV2L KOcells and we found elevated IFNβ and IFNλ responses had been
reducedbythere-expressionofSKIV2LinKOcells.

Furthermore, we investigated which innate sensing pathway is
responsible for the upregulated IFN response in SKIV2L KO cellsby the knockdown experiment of different innate immune sensors
retinoic

acid-inducible

antiviral-signaling

gene

proteinDifferentiation-Associatedgene

I(RIG-I),(MAVS)
5

mitochondrialandMelanoma(MDA5).

Knockdown

experiment of innate immune sensors reflected upregulation ofIFNβ and IFNλ in SKIV2L KO cells mediated by RIG I pathway.
Afterward to confirm the role of SKIV2L in maintaining
constitutive weak IFN response, we transfected WT and KO cells
RNA into THP-1 cells. Introduction of SKIV2L KO RNA in THP-1
cells enhanced both IFNβ and IFNλ mRNA expressions
significantly. Stimulations of SKIV2L KO cells RNA also induced
pro-inflammatory cytokines IL-6, TNF-α, and IP-10 in THP-1
cells. We also found knockdown of SKIV2L enhanced IFNβ andIL-29 expression in THP-1 cells. Moreover, we compared theIFN-β, IFNλ, and NFκB gene promoters activity between
HEK-293T WT and HEK293T SKIV2L KO cells by stimulating
thapsigargin at different concentration to ensure the role ofSKIV2L in innate immunity. Thapsigargin is an inhibitor of sarco
endoplasmic reticulum Ca2+–ATPase (SERCA), depletes Ca2+
store in the ER and thereby causes ER stress, leads to theaccumulation of unfolded proteins in the ER. Stimulation ofthapsigargin induced IFN-β, IFN-λ, and NFκB gene activation
more significantly in a dose dependent manner in KO cells thanthe WT cells. It had been reported that an organogermanium
compound 3-(trihydroxygermyl) propanoic acid (THGP), caninhibit RIG-I mediated IFN induction [Baidya S. et al, Viruses
2021, 13(9), 1674], in consistent with the previous reports, we hadfound THGP can restrain the elevated IFN response in SKIV2LKO cells. In future we will find out whether increased ISG
signature would also be found in SKIV2L KO cell throughtranscriptome analysis. We are looking for THES patients inBangladesh, as THES is very rare genetic disorder, we could not
find any THES patient yet. We hope if we get THES patients
samples that would be a great resource to execute our future joint
research plan. In the long run we will try to elucidate themechanism of regulation of constitutive weak IFN response bySKIV2L. Moreover, Bangladesh has several patients diagnosed
with Idiopathic Granulomatous Mastitis (IGM), which is a rare
chronic inflammatory lesion of the breast that can clinically andradiographically mimic breast carcinoma. There is no evidence ofSKIV2L deficiency or mutation in IGM patients. We are planningto do the genetic analysis of SKIV2L in IGM patients and if weget any positive result, that will help us to explain inflammatory
symptoms of IGM patients and we would also be able to step

forward to identify the role of SKIV2L in innate immunity. If so,that will show us a way to find out a suitable agonist of SKIV2L,
which could be a possible therapeutic agent to reduce enhanced
IFN response not only in SKIV2L deficient patients but also in
different

autoimmune

diseasepatients

hyperactivation of type I IFN response.
【Conference, symposium, workshop etc.】

Publication*Entertheinformationofconference or journal (vol. page.

Not presented yetYear.) where the above work
was presented.
【Journals】
Not published yet

causedbythe