key: cord-1046330-xu6t5kwz
authors: de Oliveira, Miriane; Sakalem, Marna Eliana; De Sibio, Maria Teresa; Mathias, Lucas Solla; Rodrigues, Bruna Moretto; Nogueira, Célia Regina
title: Irisin modulates genes associated with severe coronavirus disease (COVID-19) outcome in human subcutaneous adipocytes
date: 2020-06-25
journal: Mol Cell Endocrinol
DOI: 10.1016/j.mce.2020.110917
sha: 1af6e17d758b5de98910207a88a7fb33803d9963
doc_id: 1046330
cord_uid: xu6t5kwz

Obesity patients are more susceptible to develop COVID-19 severe outcome due to the role of angiotensin-converting enzyme 2 (ACE2) in the viral infection. ACE2 is regulated in the human cells by different genes associated with increased (TLR3, HAT1, HDAC2, KDM5B, SIRT1, RAB1A, FURIN and ADAM10) or decreased (TRIB3) virus replication. RNA-seq data revealed 14857 genes expressed in human subcutaneous adipocytes, including genes mentioned above. Irisin treatment increased by 3-fold the levels of TRIB3 transcript and decreased the levels of other genes. The decrease in FURIN and ADAM10 expression enriched diverse biological processes, including extracellular structure organization. Our results indicate a positive effect of irisin on the expression of multiple genes related to viral infection in the adipose tissue; furthermore, translatable for other tissues and organs targeted by the novel coronavirus and present, thus, promising approaches for the treatment of COVID-19 infection as therapeutic strategy to decrease ACE2 regulatory genes.

Obesity is the most common metabolic disorder in the world, and is a public health problem 29 that affects both developed and developing countries (1-3). The amount and distribution of adipose 30 tissue is associated with many adverse consequences, such as hypertension, type II diabetes, 31 cardiovascular diseases (4), and may lead to decreased expiratory reserve volume (5).

The emergence and spread of 2019 severe acute respiratory syndrome coronavirus 2 (SARS- 

In face of this scenario, of a highly infective disease with potential to cause death, it has been 45 previously shown that people with a pre-existing chronic medical condition such as obesity are more 46 susceptible to develop severe COVID-19 outcomes (10). Obesity has an impact on pulmonary 47 response to COVID-19, especially in obese and diabetic individuals; in these individuals, the ACE2 58 is increased which turns adipose tissue into a potential target and viral reservoir (15) . 59 Recently, a molecular study conducted with 700 lung transcriptome samples from patients 60 with comorbidities, cardiovascular diseases, familial primary pulmonary hypertension, hypertension 61 and pulmonary hypertension, associated with severe COVID-19 showed that ACE2 is more 62 expressed in these patients than in control individuals (16). In addition, there are other reports that 63 contain other several genes with potential importance for SARS-CoV-2 cell cycle and 

In a study with transcriptional analyzes of proteins that interact with SARS-CoV-2, altered 74 transcripts in aging lung were observed, such as increased hyaluronan and proteoglycan link protein 75 2 (HAPLN2), and decreased while tribbles homolog 3 (TRIB3) (18). TRIB3, mainly expressed in type 76 I (AT1) and type II (AT2) alveolar cells (19), is probably the common target as a protective factor 77 for other viruses, as it has been previously shown for flavivirus dengue and Zika (20), and the 78 increased replication of hepatitis C virus (HCV) was associated with its inhibition (21). TRIB3 79 interacts with nucleocapsid protein and RNA-dependent RNA polymerase of human coronavirus 80 (HCoVs) may decrease virus infection and replication (18).

Irisin is a cleaved peptide formed from the fibronectin type III domain-containing protein 5 82 (FNDC5) (22), which directs white adipose tissue to brown adipose tissue with increased 83 thermogenesis, which was suggested as a therapeutic agent for human metabolic disease such as 84 obesity (23). It has been postulated that irisin modulates macrophage activity by reducing reactive 85 oxygen species (ROS) overproduction, which could suggest its potential anti-inflammatory 86 properties, with possible important action also in the course of lung injury (24). Seq analysis was selected in order to perform a "free" investigation of the genes expressed in the 97 cells, because RNA-Seq does not require predesigned probes, the data sets are unbiased, allowing for 98 hypothesis-free experimental design. transcript level was increased by 3-fold compared to the control group. TLR3 and SIRT1 genes were 152 decreased in the presence of irisin; HDAC2 was elevated, and HAT1 and RAB1A expression were not 153 altered by irisin action (Fig.3) . (22, 26, 27, 32) , it must be considered that the major reason behind this outcome is its the 179 ability of irisin to induce adipocyte browning, in a process known as irisin's canonical function, which largely depends on the experimental conditions or the distinct adipocyte subsets used (33-37).

In a research from 2015, Kristóf and colleagues (36) suggest that irisin is able to induce a "beige" 182 program in differentiating human primary subcutaneous white adipocytes, and not effectively 183 browning; the protocol used consisted of irisin administration during the whole differentiation 184 procedure, or in the last four days of the differentiation, and the cell lineage employed was of 185 preadipocytes. In addition, Lee and coworkers (34) showed that FNDC5 improved thermogenesis in 186 subcutaneous but not omental adipocytes, and the magnitude of thermogenic activation was less 187 evident compared to those observed in neck adipocytes. Therefore, despite the divergent results in The authors have nothing to disclose. Larger circles represent general terms and smaller circles represent specific terms; terms joined by lines 527 indicate a relationship between them; 12 terms are represented in the REVIGO analysis. 528 529 TRIB3 was elevated by Irisin 530 Figure 3: Irisin effect on FURIN, ADAM10, TLR3, HAT1, HDAC2, SIRT1, RAB1A, KDM5B and TRIB3 , 531 in subcutaneous adipocytes: Human subcutaneous adipocytes were treated with 20nm irisin for 24h, after 532 this period the RNA extraction, preparation and sequencing was performed. Bioinformatics analysis was 533 performed using Kallisto software. a) FURIN, b) ADAM10, c) TLR3, f) SIRT1 and h) KDM5B were decreased 534 by irisin e) HDAC2 and i) TRIB3 were elevated by irisin. The values expressed in fragments per kilobase of 535 exon model per million reads mapped (FPKM), from RNA-seq, were used to compare irisin group (Ir) with 536 control (C); using Student's t-test to compare results, after performing the Kolmogorov Smirnov normality 537 test. Data are expressed as mean ± standard deviation. The significance level was set at 5%. ** P<0.001, *** 538 P<0.0001 n=3, ns= non significant. 539 540

growth GO:0016049 7

extracellular structure organization GO:0043062 1

TreeMap analysis for the terms involves ADAM10 and other genes Down regulated by Irisin. The grouped terms and the enriched genes are represented for each main term found after the TreeMap cluster analysis

Note: This board shows: the GO terms that includes FURIN (enriched in the set of genes down-regulated by irisin) and their description, the adjusted q-value, the number of geneIDs to each term_description is showed, highlighted FURIN (ID5045). Board 1: TreeMap analysis for the terms involves FURIN and other genes Down regulated by Irisin. The grouped terms and the enriched genes are represented for each main term found after the TreeMap cluster analysis; 14 terms are grouped into 6 main terms (Representative_term).

Note: This board shows: the GO terms that includes ADAM10 (enriched in the set of genes down-regulated by irisin) and their description, the adjusted q-value, the number of geneIDs to each term_description is showed, highlighted ADAM10 (ID102). 2. TRIB3 is increased by irisin.3. Irisin diminished FURIN and ADAM10 in human subcutaneous adipocytes.