GPR183 antagonism reduces macrophage infiltration in influenza and SARS-CoV-2 infection

Abstract

RationaleSevere viral respiratory infections are often characterised by extensive myeloid cell infiltration and activation and persistent lung tissue injury. However, the immunological mechanisms driving excessive inflammation in the lung remain poorly understood.ObjectivesTo identify the mechanisms that drive immune cell recruitment in the lung during viral respiratory infections and identify novel drug targets to reduce inflammation and disease severity.MethodsPreclinical murine models of influenza virus and severe acute respiratory coronavirus 2 (SARS-CoV-2) infection.ResultsOxidised cholesterols and the oxysterol-sensing receptor GPR183 were identified as drivers of monocyte-macrophage infiltration to the lung during influenza virus (IAV) and SARS-CoV-2 infection. Both IAV and SARS-CoV-2 infection upregulated the enzymes cholesterol 25-hydroxylase (CH25H) and cytochrome P450 family 7 subfamily member B1 (CYP7B1) in the lung, resulting in local production of the oxidised cholesterols 25-hydroxycholesterol (25-OHC) and 7α,25-dihydroxycholesterol (7α,25-OHC). Loss-of-function mutation of GPR183, or treatment with a GPR183 antagonist, reduced macrophage infiltration and inflammatory cytokine production in the lungs of IAV- or SARS-CoV-2-infected mice. The GPR183 antagonist significantly attenuated the severity of SARS-CoV-2 infection and viral loads. Analysis of single cell RNASeq data on bronchoalveolar lavage samples from healthy controls and COVID-19 patients with moderate and severe disease revealed thatCH25H, CYP7B1andGPR183are significantly upregulated in macrophages during COVID-19.ConclusionThis study demonstrates that oxysterols drive inflammation in the lungviaGPR183 and provides the first preclinical evidence for therapeutic benefit of targeting GPR183 during severe viral respiratory infections.

Oxysterol metabolism dictates macrophage influx during SARS-CoV-2 infection

“…In contrast, more recently Fessler et al [37] using transgenic mice expressing human ACE2 under the epithelial K18 promoter and infected with the USA-WA1/2020 SARS-CoV-2 strain, revealed that 25-OHC did not modify viral clearance from the lungs. Similar to the study presented here [9], Fessler et al also reported upregulation of Ch25h in the lungs of mice infected with SARS-CoV-2 [37]. In contrast however, using the transgenic human ACE2 mice and the USA-WA1/2020 SARS-CoV-2 strain, Fessler et al [37] did not observe any effect on SARS-CoV-2 clearance or disease outcome following treatment with GPR183 antagonism, which may be a facet of both the mouse and viral strains used.…”

“…25-OHC can then be metabolized further by 25-OHC 7α-hydroxylase (CYP7B1) to 7α,25-OHC that contains an additional hydroxyl group at position 7α [22]. 7α,25-OHC has been described as the predominant ligand for GPR183 [11,12], as examined in this current study by Foo et al where it regulated macrophage recruitment to the lungs [9]. GPR183 is a G protein-coupled receptor expressed on monocytes, macrophages [23] and lymphocytes where it guides B cell movement along the T-B cell border and through B cell follicles of secondary lymphoid organs [24,25] and CD4 T cell positioning within lymph nodes [26].…”

“…To further elaborate on the role of oxysterols in lung infection, Foo et al here [9] first demonstrate that infection of mice with the H1N1 variant of influenza A virus (IAV) resulted in increased expression of Ch25h and Cyp7b1 mRNA concomitant with increased protein and the oxysterols 25-OHC and 7α,25-OHC in both lung homogenates and BALF. This was accompanied by increased expression of the 7α,25-OHC receptor GPR183 in BAL cells.…”

“…To generate a symptomatic murine SARS-CoV-2 virus Foo et al [9] passaged the Beta variant of SARS-CoV-2 (B.1.351) four times in B6 mice, which resulted in a NSP5 mutation causing clinical signs in infected mice. Similar to infection with IAV, this resulted in increased expression of Ch25h and Cyp7b1 mRNA concomitant with increased protein and the oxysterols 25-OHC and 7α,25-OHC in both lung homogenates and BALF.…”

Oral CBD treatment is associated with an anti-inflammatory gene expression signature in myeloid cells of people living with HIV

“…Five out of six genes show a positive role in the inflammation process: CXCL8 (interleukin-8) is a member of the chemokine family involved in cell recruitment and activation under inflammatory conditions 21 ; EREG is a pro-inflammatory gene with a role in tissue healing and vascularization 22 ; JUN and FOS are two genes expressed in monocytes and macrophages involved in promoting inflammation 23,24 , and both are included as markers in a recently general inflammatory macrophage activation phenotype encompassing responses to HIV, sepsis, and SARS-CoV-2 25 ; CCL3 is a pro-inflammatory gene and one of the major HIV-suppressive factors produced by CD8+ T-cells and monocytes 25,26 . Other proinflammatory genes appear among the top underexpressed genes (Table 1): GPR183 plays a role in attracting macrophages during viral inflammation 27 ; MIR23AHG is a long non-coding RNA gene promoting inflammation polarization in macrophages 28 and associated to chronic inflammation in ulcerative colitis 29 ; TIPARP is an antiviral gene, with a specific anti-HIV-1 effect in monocytes 30 ; NAMPT is a gene involved in the inflammatory responses activation with cytokine-like behavior 31 ; IL1B is a pro-inflammatory cytokine 32,33 ; and KLF6 is known to regulate macrophage polarization towards the proinflammatory phenotype 34 . In summary, five out of six DEGs and several of the top underexpressed genes are markedly involved in inflammatory processes of myeloid cells.…”