Mechanism of IL-17 Signaling Pathway in Spleen Inflammatory Response Induced by Altitude Hypoxia in Mice

YONG Sheng, GUO Yujing, CHEN Xiaochen, XU Yuzhen, HU Ying


To explore the mechanism of spleen tissue inflammatory response induced by altitude hypoxia in mice.Methods C57BL/6 mice were randomly assigned to a plain, i.e., low-altitude, normoxia group and an altitude hypoxia group, with 5 mice in each group. In the plain normoxia group, the mice were kept in a normoxic environment at the altitude of 400 m above sea level (with an oxygen concentration of 19.88%). The mice in the altitude hypoxia group were kept in an environment at the altitude of 4200 m above sea level (with an oxygen concentration of 14.23%) to establish the animal model of altitude hypoxia. On day 30, spleen tissues were collected to determine the splenic index. HE staining was performed to observe the histopathological changes in the spleen tissues of the mice. Real time fluorogenic quantitative PCR (RT-qPCR) and Western blot were conducted to determine the mRNA and protein expressions of interleukin (IL)-6, IL-12, and IL-1β in the spleen tissue of the mice. High-throughput transcriptome sequencing was performed with RNA sequencing (RNA-seq). KEGG enrichment analysis was performed for the differentially expressed genes (DEGs). The DEGs in the key pathways were verified by RT-qPCR.Results Compared with the plain normoxia group, the mice exposed to high-altitude hypoxic environment had decreased spleen index (P<0.05) and exhibited such pathological changes as decreased white pulp, enlarged germinal center, blurred edge, and venous congestion. The mRNA and protein expression levels of IL-6, IL-12, and IL-1β in the spleen tissue of mice in the altitude hypoxia group were up-regulated (P<0.05). According to the results of transcriptome sequencing and KEGG pathway enrichment analysis, 4218 DEGs were enriched in 178 enrichment pathways (P<0.05). DEGs were significantly enriched in multiple pathways associated with immunity and inflammation, such as T cell receptor signaling pathway, TNF signaling pathway, and IL-17 signaling pathway (P<0.05) in the spleen of mice exposed to high-altitude hypoxic environment. Among them, IL-17 signaling pathway and the downstream inflammatory factors were highly up-regulated (P<0.05). Compared with the plain normoxia group, the mRNA expression levels of key genes in the IL-17 signaling pathway, including IL-17, IL-17R, and mitogen-activated protein kinase genes (MAPKs), and the downstream inflammatory factors, including matrix metallopeptidase 9 (MMP9), S100 calcium binding protein A8 gene (S100A8), S100 calcium binding protein A9 gene (S100A9), and tumor necrosis factor α (TNF-α), were up-regulated or down-regulated (P<0.05) in the altitude hypoxia group. According to the validation of RT-qPCR results, the mRNA expression levels of DEGs were consistent with the RNA-seq results.Conclusion  Altitude hypoxia can induce inflammatory response in the mouse spleen tissue by activating IL-17 signaling pathway and promoting the release of downstream inflammatory factors.

Keywords: Altitude hypoxia,  Transcriptomics,  IL-17 signaling pathway,  Spleen tissue,  Inflammation,  RNA-sequencing,  Bioinformatics

Full Text:



MARTINELLO K A, MEEHAN C, AVDIC-BELLTHEUS A, et al. Acute LPS sensitization and continuous infusion exacerbates hypoxic brain injury in a piglet model of neonatal encephalopathy. Sci Rep,2019,9(1): 10184. doi: 10.1038/s41598-019-46488-y.

REN C Z, LUO Y L, LIU Y Q, et al. Effects of astragalus and lily particles on free radical metabolize and pathological changes of lung in mice under plateau hypoxia condition. J Chongqing Med Univ,2017, 42(9): 1126–1130. doi: 10.13406/j.cnki.cyxb.001010.

LEWIS S M, WILLIAMS A, EISENBARTH S C. Structure and function of the immune system in the spleen. Sci Immunol,2019,4(33): eaau6085. doi: 10.1126/sciimmunol.aau6085.

NORRIS P C, LIBREROS S, SERHAN C N. Resolution metabolomes activated by hypoxic environment. Sci Adv,2019,5(10): eaax4895. doi: 10.1126/sciadv.aax4895.

HANCKOVÁ M, MIHÁLIKOVÁ L, PASTOREKOVÁ S, et al. Hypoxia alters the immune response in mouse peritoneal macrophages infected with influenza a virus with truncated NS1 protein. Cytokine,2023,164: 156138. doi: 10.1016/j.cyto.2023.156138.

XU X, LI H, WEI Q, et al. Novel targets in a high-altitude pulmonary hypertension rat model based on RNA-seq and proteomics. Front Med (Lausanne),2021,8: 742436. doi: 10.3389/fmed.2021.742436.

YANG M, WU S, CAI W, et al. Hypoxia-induced MIF induces dysregulation of lipid metabolism in Hep2 laryngocarcinoma through the IL-6/JAK-STAT pathway. Lipids Health Dis,2022,21(1): 82. doi: 10.1186/s12944-022-01693-z.

PANKOKE S, SCHWEITZER T, BIKKER R, et al. Obesity impacts hypoxia adaptation of the lung. Am J Physiol Lung Cell Mol Physiol, 2023,325(3): L352–L359. doi: 10.1152/ajplung.00125.2023.

JOHNSON J, YANG Y J, BIAN Z L, et al. Systemic hypoxemia induces cardiomyocyte hypertrophy and right ventricular specific induction of proliferation. Circ Res,2023,132(6): 723–740. doi: 10.1161/Circresaha. 122.321604.

LI H Q,HU Y,XU Y Z, et al. Study on effect of plateau hypoxia on mice spleen using transcriptome sequencing. Chinese J Immunol,2023,39(1): 11–17. doi: 10. 3969/j. issn. 1000-484X. 2023. 01. 002.

MCGETTRICK A F, O'NEILL L A J. The role of HIF in immunity and inflammation. Cell Metab,2020,32(4): 524–536. doi: 10.1016/j.cmet.2020. 08.002.

PURDY G M, JAMES M A, REES J L, et al. Spleen reactivity during incremental ascent to altitude. J Appl Physiol (1985),2019,126(1): 152–159. doi: 10.1152/japplphysiol.00753.2018.

STORJORD E, HENNO L T, MOLLNES T E, et al. Analysis of cytokines. Tidsskr Nor Laegeforen,2020,140(1). doi: 10.4045/tidsskr.18. 0961.

KANG S, KISHIMOTO T. Interplay between interleukin-6 signaling and the vascular endothelium in cytokine storms. Exp Mol Med,2021,53(7): 1116–1123. doi: 10.1038/s12276-021-00649-0.

WANG W, XU Z, ZHANG J, et al. Tim-3 is a potential regulator that inhibits monocyte inflammation in response to intermittent hypoxia in children with obstructive sleep apnea syndrome. Clin Immunol,2021, 222: 108641. doi: 10.1016/j.clim.2020.108641.

MANTOVANI A, DINARELLO C A, MOLGORA M, et al. Interleukin-1 and related cytokines in the regulation of inflammation and immunity. Immunity,2019,50(4): 778–795. doi: 10.1016/j.immuni.2019.03.012.

MEEHAN E V, WANG K. Interleukin-17 family cytokines in metabolic disorders and cancer. Genes (Basel),2022,13(9): 1643. doi: 10.3390/genes13091643.

FENG Y, ZHENG C, ZHOU Z, et al. IL-17A neutralizing antibody attenuates eosinophilic meningitis caused by angiostrongylus cantonensis by involving IL-17RA/Traf6/NF-kappaB signaling. Exp Cell Res,2019, 384(1): 111554. doi: 10.1016/j.yexcr.2019.111554.

DU S, LI Z, XIE X, et al. IL-17 stimulates the expression of CCL2 in cardiac myocytes via Act1/TRAF6/p38MAPK-dependent AP-1 activation. Scand J Immunol,2020,91(1): e12840. doi: 10.1111/sji.12840.

SWAIDANI S, LIU C, ZHAO J, et al. TRAF regulation of IL-17 cytokine signaling. Front Immunol,2019,10: 1293. doi: 10.3389/fimmu. 2019.01293.

health and disease. Int Immunol,2021,33(12): 723–729. doi: 10.1093/intimm/dxab075.

IIDA S, NAKANISHI T, MOMOSE F, et al. IL-17A is the critical cytokine for liver and spleen amyloidosis in inflammatory skin disease. Int J Mol Sci,2022,23(10): 5726. doi: 10.3390/ijms23105726.

ALVAREZ-COIRADAS E, MUNTEANU C R, DIAZ-SAEZ L, et al. Discovery of novel immunopharmacological ligands targeting the IL-17 inflammatory pathway. Int Immunopharmacol,2020,89(Pt A): 107026. doi: 10.1016/j.intimp.2020.107026.

WEN X, YIN Y, LI X, et al. Effect of miR-26a-5p targeting ADAM17 gene on apoptosis, inflammatory factors and oxidative stress response of myocardial cells in hypoxic model. J Bioenerg Biomembr,2020,52(2): 83–92. doi: 10.1007/s10863-020-09829-5.

WU Y, WEI H, LI P, et al. Quercetin administration following hypoxia-induced neonatal brain damage attenuates later-life seizure susceptibility and anxiety-related behavior: modulating inflammatory response. Front Pediatr,2022,10: 791815. doi: 10.3389/fped.2022.791815.

GUARDADO S, OJEDA-JUAREZ D, KAUL M, et al. Comprehensive review of lipocalin 2-mediated effects in lung inflammation. Am J Physiol Lung Cell Mol Physiol,2021,321(4): L726–L733. doi: 10.1152/ajplung. 00080.2021.

WU M, XU L, WANG Y, et al. S100A8/A9 induces microglia activation and promotes the apoptosis of oligodendrocyte precursor cells by activating the NF-κB signaling pathway. Brain Res Bull,2018,143(12): 234–245. doi: 10.1016/j.brainresbull.2018.09.014.

DONG Y, ZHAO H, MAN J, et al. MMP-9-mediated regulation of hypoxia-reperfusion injury-related neutrophil inflammation in an in vitro proximal tubular cell model. Ren Fail,2021,43(1): 900–910. doi: 10.1080/ 0886022X.2021.1930558.


  • There are currently no refbacks.