LDN diminished LPS induced cytokine storm.
Cytokine storm is a very commonly observed factor in most severe COVI19
patients and also one of the leading causes of
mortality5–7. Peripheral blood of severe COVID-19
patients has also shown a high level of cytokine
storm14. Keeping in mind the ability of
lipopolysaccharide (LPS) to cause sepsis and triggers an uncontrolled
systemic inflammatory response in murine macrophage
cells15, we treated macrophage cells with LPS (1μg/ml)
in presence and absence of LDN (5 μM). Results demonstrated that LPS
treatment significantly induced expression on pro-inflammatory cytokines
(IL-1β, IL-6and TNF-a) whereas, LDN significantly inhibited LPS
expression of IL-1β, IL-6and TNF-a in macrophage cells (Fig.
1A ). Adipose tissue macrophage (ATM) is closely linked to this
inflammatory condition which leads to numbers of diseases and the
ability of HFD feeding on increased LPS uptake and trafficking to
macrophages and other targets are well known16. Hence
in this study, we investigated the effect of High Fat Diet (HFD) on
cytokines expression in purified ATMs. Expression of pro-inflammatory
markers such as IL-1β , TNF-a, and IL6 was induced
(Fig-1B ) whereas LDN attenuates HFD induced expression profile
of pro-inflammatory cytokine. LDN shows a protective (by reducing
elevated M1 cytokines) from HFD mediated inflammation. Next, we tested
the possible involvement of High Fat Diet (HFD) in inducing the release
of proinflammatory cytokines, and we also determine the effects of LDN
on release of proinflammatory mediators in HFD mice model (Fig
1C ). Serum from HFD mice show a significantly enhanced release
proinflammatory mediators (IL-1Β, TNF-α and IL-6) and interestingly we
found that LDN treatment attenuated HFD induced serum IL-1Β, TNF-α and
IL-6 level (Fig-1C ). Cell viability was determined by utilizing
MTT assay in macrophage cell line. The assay revealed that the selected
range of dose is safe and did not affect cell viability at the different
doses exposed (Fig S1). These data suggest that HFD diet induced mice
persuaded the release of various pro-inflammatory mediators, LDN
treatment can significantly abrogate HFD induced release of
proinflammatory mediators in serum.