SARS-CoV-2 Variants of Concern Infect the Respiratory Tract and Induce Inflammatory Response in Wild-Type Laboratory Mice

The emergence of new severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) variants of concern pose a major threat to public health, due to possible enhanced virulence, transmissibility and immune escape. These variants may also adapt to new hosts, in part through mutations in the spike protein. In this study, we evaluated the infectivity and pathogenicity of SARS-CoV-2 variants of concern in wild-type C57BL/6 mice. Six-week-old mice were inoculated intranasally with a representative virus from the original B.1 lineage, or the emerging B.1.1.7 and B.1.351 lineages. We also infected a group of mice with a mouse-adapted SARS-CoV-2 (MA10). Viral load and mRNA levels of multiple cytokines and chemokines were analyzed in the lung tissues on day 3 after infection. Our data show that unlike the B.1 virus, the B.1.1.7 and B.1.351 viruses are capable of infecting C57BL/6 mice and replicating at high concentrations in the lungs. The B.1.351 virus replicated to higher titers in the lungs compared with the B.1.1.7 and MA10 viruses. The levels of cytokines (IL-6, TNF-α, IL-1β) and chemokine (CCL2) were upregulated in response to the B.1.1.7 and B.1.351 infection in the lungs. In addition, robust expression of viral nucleocapsid protein and histopathological changes were detected in the lungs of B.1.351-infected mice. Overall, these data indicate a greater potential for infectivity and adaptation to new hosts by emerging SARS-CoV-2 variants.

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SARS-CoV-2 variants of concern infect the respiratory tract and induce inflammatory response in wild-type laboratory mice

10.1101/2021.09.29.462373 ◽

2021 ◽

Author(s):

Shannon Stone ◽

Hussin A. Rothan ◽

Janhavi P. Natekar ◽

Pratima Kumari ◽

Shaligram Sharma ◽

...

Keyword(s):

Immune Escape ◽

Mrna Levels ◽

Laboratory Mice ◽

Wild Type ◽

The Public ◽

Cytokines And Chemokines ◽

Tnf Α ◽

New Hosts ◽

High Concentrations ◽

Old Mice

AbstractThe emergence of new severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) variants of concern poses a major threat to the public health due to possible enhanced virulence, transmissibility and immune escape. These variants may also adapt to new hosts in part through mutations in the spike protein. In this study, we evaluated the infectivity and pathogenicity of SARS-CoV-2 variants of concern in wild-type C57BL/6 mice. Six-week-old mice were inoculated intranasally with a representative virus from the original B.1 lineage or emerging B.1.1.7 and B.1.351 lineages. We also infected a group of mice with a mouse-adapted SARS-CoV-2 (MA10). Viral load and mRNA levels of multiple cytokines and chemokines were analyzed in the lung tissues on day 3 after infection. Our data show that unlike the B.1 virus, the B.1.1.7 and B.1.351 viruses are capable of infecting C57BL/6 mice and replicating at high concentrations in the lungs. The B.1.351 virus replicated to higher titers in the lungs compared to the B.1.1.7 and MA10 viruses. The levels of cytokines (IL-6, TNF-α, IL-1β) and chemokine (CCL2) were upregulated in response to the B.1.1.7 and B.1.351 infection in the lungs. Overall, these data indicate a greater potential for infectivity and adaptation to new hosts by emerging SARS-CoV-2 variants.

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Effect of Heme Oxygenase-1 Overexpression in Two Models of Lung Inflammation

Experimental Biology and Medicine ◽

10.1177/15353702-0322805-02 ◽

2003 ◽

Vol 228 (5) ◽

pp. 442-446 ◽

Cited By ~ 49

Author(s):

A. Zampetaki ◽

T. Minamino ◽

S.A. Mitsialis ◽

S. Kourembanas

Keyword(s):

Transgenic Mice ◽

Heme Oxygenase ◽

Lung Inflammation ◽

Heme Oxygenase 1 ◽

Mrna Levels ◽

Wild Type ◽

Pronounced Increase ◽

Protein Levels ◽

Cytokines And Chemokines ◽

Genetically Engineered Mice

An increasing number of studies implicate heme oxygenase-1 (HO-1) in the regulation of inflammation. Although the mechanisms involved in this cytoprotection are largely unknown, HO-1 and its enzymatic products, carbon monoxide and bilirubin, downregulate the inflammatory response by either attenuating the expression of adhesion molecules and thus inhibiting leukocyte recruitment or by repressing the induction of cytokines and chemokines. In the present study we used genetically engineered mice that express high levels of a human cDNA HO-1 transgene in lung epithelium to assess the effect of HO-1 on lung inflammation. Two separate models of inflammation were studied: hypoxic exposure and lipopolysaccharide (LPS) challenge. We found that both mRNA and protein levels of specific cytokines and chemokines were significantly elevated in response to hypoxia in the lungs of wild-type mice after 2 and 5 days of exposure but significantly suppressed in the hypoxic lungs of transgenic mice, suggesting that inhibition of these cytokines was caused by overexpression of HO-1. However, LPS treatment resulted in a very pronounced increase in mRNA levels of several cytokines in both wild-type and transgenic mice. Despite the high mRNA levels, significantly lower cytokine protein levels were detected in the bronchoalveolar lavage of HO-1 overexpressing mice compared with wild type, indicating that HO-1 leads to repression of cytokines in the airway. These results demonstrate that HO-1 activity operates through distinct molecular mechanisms to confer cytoprotection in the hypoxic and the LPS models of inflammation.

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Role of α2-macroglobulin in fever and cytokine responses induced by lipopolysaccharide in mice

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00746.2001 ◽

2002 ◽

Vol 283 (1) ◽

pp. R218-R226 ◽

Cited By ~ 24

Author(s):

Alexander V. Gourine ◽

Valery N. Gourine ◽

Yohannes Tesfaigzi ◽

Nathalie Caluwaerts ◽

Fred Van Leuven ◽

...

Keyword(s):

Mrna Level ◽

Physiological Role ◽

Mrna Levels ◽

Wild Type ◽

Cytokine Responses ◽

Α2 Macroglobulin ◽

Tnf Α ◽

Factor Α ◽

Necrosis Factor

α2-Macroglobulin (α2M) is not only a proteinase inhibitor in mammals, but it is also a specific cytokine carrier that binds pro- and anti-inflammatory cytokines implicated in fever, including interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α). To define the role of α2M in regulation of febrile and cytokine responses, wild-type mice and mice deficient in α2M (α2M −/−) were injected with lipopolysaccharide (LPS). Changes in body temperature as well as plasma levels of IL-1β, IL-6, and TNF-α and hepatic TNF-α mRNA level during fever in α2M −/− mice were compared with those in wild-type control mice. The α2M −/− mice developed a short-term markedly attenuated (ANOVA, P < 0.05) fever in response to LPS (2.5 mg/kg ip) compared with the wild-type mice. At 1.5 h after injection of LPS, the plasma concentration of TNF-α, but not IL-1β or IL-6, was significantly lower (by 58%) in the α2M −/− mice compared with their wild-type controls (ANOVA, P < 0.05). There was no difference in hepatic TNF-α mRNA levels between α2M −/− and wild-type mice 1.5 h after injection of LPS. These data support the hypotheses that 1) α2M is important for the normal development of LPS-induced fever and 2) a putative mechanism of α2M involvement in fever is through the inhibition of TNF-α clearance. These findings indicate a novel physiological role for α2M.

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Accelerated Prion Replication in, but Prolonged Survival Times of, Prion-Infected CXCR3−/− Mice

Journal of Virology ◽

10.1128/jvi.01371-08 ◽

2008 ◽

Vol 82 (24) ◽

pp. 12464-12471 ◽

Cited By ~ 30

Author(s):

Constanze Riemer ◽

Julia Schultz ◽

Michael Burwinkel ◽

Anja Schwarz ◽

Simon W. F. Mok ◽

...

Keyword(s):

Gene Expression ◽

Prion Diseases ◽

Proteinase K ◽

Prolonged Survival ◽

Disease Development ◽

Mrna Levels ◽

Wild Type ◽

Survival Times ◽

Cytokines And Chemokines ◽

Asymptomatic Stage

ABSTRACT Prion diseases have a significant inflammatory component. Glia activation, which is associated with increased production of cytokines and chemokines, may play an important role in disease development. Among the chemokines upregulated highly and early upregulated during scrapie infections are ligands of CXCR3. To gain more insight into the role of CXCR3 in a prion model, CXCR3-deficient (CXCR3−/−) mice were infected intracerebrally with scrapie strain 139A and characterized in comparison to similarly infected wild-type controls. CXCR3−/− mice showed significantly prolonged survival times of up to 30 days on average. Surprisingly, however, they displayed accelerated accumulation of misfolded proteinase K-resistant prion protein PrPSc and 20 times higher infectious prion titers than wild-type mice at the asymptomatic stage of the disease, indicating that these PrP isoforms may not be critical determinants of survival times. As demonstrated by immunohistochemistry, Western blotting, and gene expression analysis, CXCR3-deficient animals develop an excessive astrocytosis. However, microglia activation is reduced. Quantitative analysis of gliosis-associated gene expression alterations demonstrated reduced mRNA levels for a number of proinflammatory factors in CXCR3−/− compared to wild-type mice, indicating a weaker inflammatory response in the knockout mice. Taken together, this murine prion model identifies CXCR3 as disease-modifying host factor and indicates that inflammatory glial responses may act in concert with PrPSc in disease development. Moreover, the results indicate that targeting CXCR3 for treatment of prion infections could prolong survival times, but the results also raise the concern that impairment of microglial migration by ablation or inhibition of CXCR3 could result in increased accumulation of misfolded PrPSc.

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Extracellular purine metabolism and signaling of CD73-derived adenosine in murine Treg and Teff cells

AJP Cell Physiology ◽

10.1152/ajpcell.00385.2010 ◽

2011 ◽

Vol 301 (2) ◽

pp. C530-C539 ◽

Cited By ~ 83

Author(s):

Michael Romio ◽

Benjamin Reinbeck ◽

Sabine Bongardt ◽

Sandra Hüls ◽

Sandra Burghoff ◽

...

Keyword(s):

T Cells ◽

Proinflammatory Cytokines ◽

Wild Type ◽

Murine Splenocytes ◽

Gm Csf ◽

A2a Receptors ◽

Cytokines And Chemokines ◽

Tnf Α ◽

Ifn Γ ◽

Macrophage Colony

CD73-derived adenosine acts as potent inhibitor of inflammation, and regulatory T cells (Treg) have been shown to express CD73 as a novel marker. This study explored the role of endogenously formed adenosine in modulating NF-κB activity and cytokine/chemokine release from murine Treg and effector T cells (Teff) including key enzymes/purinergic receptors of extracellular ATP catabolism. Stimulating murine splenocytes and CD4+ T cells with anti-CD3/anti-CD28 significantly upregulated activated NF-κB in CD73−/− T cells (wild type: 4.36 ± 0.21; CD73−/−: 6.58 ± 0.75; n = 4; P = 0.029). This was associated with an augmented release of proinflammatory cytokines IL-2, TNF-α, and IFN-γ. Similar changes were observed with the CD73 inhibitor APCP (50 μM) on NF-κB and IFN-γ in wild-type CD4+ T-cells. Treatment of stimulated CD4+ T-cells with adenosine (25 μM) potently reduced IFN-γ release which is mediated by adenosine A2a receptors (A2aR). AMP (50 μM) also reduced cytokine release which was not inhibited by APCP. In Teff, A2aR activation (CGS21680) potently inhibited the release of IL-1, IL-2, IL-3, IL-4, IL-12, IL-13, IFN-γ, TNF-α, granulocyte-macrophage colony-stimulating factor (GM-CSF), CCL3, and CCL4. However, in Treg, CGS21680 did not alter cytokine/chemokine release. In summary, CD73-derived adenosine tonically inhibits active NF-κB in CD4+ T-cells, thereby modulating the release of a broad spectrum of proinflammatory cytokines and chemokines. Downregulation of P2X7 and upregulation of CD73 in Treg after antigenic stimulation may be an important mechanism to maintain the ability of Treg to generate immunosuppressive adenosine.

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Protective effect of extracellular superoxide dismutase on endothelial function during aging

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.01342.2008 ◽

2009 ◽

Vol 296 (6) ◽

pp. H1920-H1925 ◽

Cited By ~ 39

Author(s):

Donald D. Lund ◽

Yi Chu ◽

Jordan D. Miller ◽

Donald D. Heistad

Keyword(s):

Superoxide Dismutase ◽

Endothelial Dysfunction ◽

Endothelial Function ◽

Ex Vivo ◽

Vascular Dysfunction ◽

Extracellular Superoxide Dismutase ◽

Mrna Levels ◽

Wild Type ◽

Vasomotor Function ◽

Old Mice

Endothelial vasomotor function decreases with increasing age. Extracellular superoxide dismutase (ecSOD) protects against vascular dysfunction in several disease states. The purpose of this study was to determine whether endogenous ecSOD protects against endothelial dysfunction in old mice. Vasomotor function of the aorta was studied ex vivo in wild-type (ecSOD+/+) and ecSOD-deficient (ecSOD−/−) mice at 11 (adult) and 29 (old) mo of age. Maximal relaxation to acetylcholine (10−4 M) was impaired in vessels from adult ecSOD−/− mice [75 ± 3% (mean ± SE)] compared with wild-type mice (89 ± 2%, P < 0.05). Maximal relaxation to acetylcholine (10−4 M) was profoundly impaired in aorta from old ecSOD−/− mice (45 ± 5%) compared with wild-type mice (75 ± 4%, P < 0.05). There was a significant correlation between expression of ecSOD and maximal relaxation to acetylcholine in adult and old mice. Tempol (1 mM), a scavenger of superoxide, improved relaxation in response to acetylcholine (63 ± 8%) in old ecSOD−/− mice ( P < 0.05), but not wild-type mice (75 ± 4%). Maximal relaxation to sodium nitroprusside was similar in aorta from adult and old wild-type and ecSOD−/− mice. Quantitative RT-PCR showed a decrease in mRNA levels of ecSOD and catalase in aorta of old mice and an increase in levels of TNFα and Nox-4 in aorta of old mice compared with adult mice. The findings support the hypothesis that impaired antioxidant mechanisms may contribute to cumulative increases in oxidative stress and impaired endothelial function in old mice. In conclusion, endogenous ecSOD plays an important role in protection against endothelial dysfunction during aging.

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Salicylate inhibits the translation and transcription of ompF in Escherichia coli

Canadian Journal of Microbiology ◽

10.1139/w01-105 ◽

2001 ◽

Vol 47 (11) ◽

pp. 1053-1057 ◽

Cited By ~ 3

Author(s):

Nat Ramani ◽

Kwaku Boakye

Keyword(s):

Escherichia Coli ◽

Membrane Protein ◽

Outer Membrane Protein ◽

Mrna Levels ◽

Strong Inhibition ◽

Wild Type ◽

High Osmolarity ◽

Number Of Factors ◽

Low Concentrations ◽

High Concentrations

OmpF is a major outer membrane protein in Escherichia coli whose expression is regulated by a large number of factors, including the osmolarity of the growth medium and the concentration of salicylate. We have previously shown that at low osmolarity, OmpF is post-transcriptionally regulated by micF mRNA, and that at high osmolarity, regulation occurs primarily by the inhibition of transcription by OmpR (Ramani et al. 1994). In contrast, salicylate was reported to alter OmpF expression solely by blocking translation primarily through micF mRNA (Rosner et al. 1991). We examined the effect of salicylate by analyzing the levels of OmpF in wild-type and micF strains grown with salicylate. At low concentrations of salicylate (04 mM), OmpF levels were inhibited strongly in wild-type cells, whereas no inhibition of OmpF was observed in the micF strain. At high concentrations of salicylate (1020 mM), both the wild type and the micF strain showed strong inhibition of OmpF. To study the effect of salicylate on transcription, ompF mRNA and micF mRNA were analyzed in wild-type cells. micF mRNA levels increased during growth with 1, 2, and 4 mM salicylate. In contrast, ompF mRNA levels were not affected by low concentrations of salicylate, but decreased strongly at 10 and 20 mM salicylate. Taken together, these results suggest that similar to osmoregulation, salicylate inhibits both the translation and transcription of ompF.Key words: salicylate, OmpF, micF, osmoregulation.

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Role of TNFR1 and TNFR2 receptors in tubulointerstitial fibrosis of obstructive nephropathy

AJP Renal Physiology ◽

10.1152/ajprenal.1999.277.5.f766 ◽

1999 ◽

Vol 277 (5) ◽

pp. F766-F772 ◽

Cited By ~ 24

Author(s):

Guangjie Guo ◽

Jeremiah Morrissey ◽

Ruth McCracken ◽

Timothy Tolley ◽

Saulo Klahr

Keyword(s):

Knockout Mice ◽

Ureteral Obstruction ◽

Collagen Iv ◽

Tubulointerstitial Fibrosis ◽

Kidney Cortex ◽

Mrna Levels ◽

Ang Ii ◽

Wild Type ◽

Interstitial Volume ◽

Tnf Α

Unilateral ureteral obstruction (UUO) results in tubulointerstitial fibrosis of the obstructed kidney. In this study, we report the contribution of tumor necrosis factor-α (TNF-α) to the fibrosis that develops after ureteral obstruction. Mice in which individual TNF-α receptors TNFR1 or TNFR2 had been genetically knocked out were used, and results were compared with mice of C57Bl/6 background after 5 days UUO. Both kidneys were removed and examined histologically for changes in interstitial volume (Vvint), collagen IV deposition, α-smooth muscle actin (α-SMA) matrix score, nuclear factor-κB (NF-κB) activity, and TNF-α mRNA levels. We found that the Vvint of contralateral unobstructed kidneys averaged ∼7% and was indistinguishable among the three genotypes of mice. Vvintof ureteral obstructed kidney of C57Bl/6 mice averaged 33 ± 3.9% after 5 days of UUO. Vvint of obstructed kidneys of TNFR1 mice was significantly reduced to 19.4 ± 3.1%, whereas that of TNFR2 mice was significantly decreased to 25.4% ± 4.8%. There was a modest but significant difference between Vvint of TNFR1 and TNFR2 ( P < 0.047). Both collagen IV and α-SMA matrix scores were decreased significantly in obstructed kidney of TNFR1 mouse compared with that of C57Bl/6 and TNFR2 mice. Nuclear extracts prepared from kidney cortex were found to have a significant increase in NF-κB binding activity in obstructed kidney compared with contralateral kidney. Individual knockout of the TNFR1 or TNFR2 genes resulted in significantly less NF-κB activation compared with the wild type, with TNFR1 being less than TNFR2 knockout. There was a significant increase in TNF-α mRNA in the kidney with ureteral obstruction in all three genotypes. TNFR1 knockout displayed a significant reduction in amount of TNF-α mRNA induced compared with wild-type or TNFR2 knockout mice. Treatment of TNFR1 knockout mice with an angiotensin converting enzyme inhibitor further decreased Vvint and TNF-α mRNA induction, suggesting an interaction of ANG II and TNF-α systems. These results suggest that TNF-α contributes, in part, to changes in interstitial volume, myofibroblast differentiation, and NF-κB activation in the kidney during ureteral obstruction. These changes appear to be mediated through both TNFR1 and TNFR2 gene products with effects through the TNFR1 receptor predominating. Furthermore, ANG II appears to stimulate TNF-α pathophysiological events leading to renal fibrosis.

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Iso-α-Acids, the Bitter Components of Beer, Suppress Microglial Inflammation in rTg4510 Tauopathy

Molecules ◽

10.3390/molecules23123133 ◽

2018 ◽

Vol 23 (12) ◽

pp. 3133 ◽

Cited By ~ 4

Author(s):

Yasuhisa Ano ◽

Yuta Takaichi ◽

Kazuyuki Uchida ◽

Keiji Kondo ◽

Hiroyuki Nakayama ◽

...

Keyword(s):

Frontal Cortex ◽

Amyloid Β ◽

Phosphorylated Tau ◽

Brain Disorders ◽

Flow Cytometry Analysis ◽

Wild Type ◽

Cytokines And Chemokines ◽

Tnf Α ◽

Aging Populations ◽

Microglial Inflammation

Due to the growth in aging populations, prevention for cognitive decline and dementia are in great demand. We previously demonstrated that the consumption of iso-α-acids (IAA), the hop-derived bitter compounds in beer, prevents inflammation and Alzheimer’s disease pathology in model mice. However, the effects of iso-α-acids on inflammation induced by other agents aside from amyloid β have not been investigated. In this study, we demonstrated that the consumption of iso-α-acids suppressed microglial inflammation in the frontal cortex of rTg4510 tauopathy mice. In addition, the levels of inflammatory cytokines and chemokines, including IL-1β and MIP-1β, in the frontal cortex of rTg4510 mice were greater than those of wild-type mice, and were reduced in rTg4510 mice fed with iso-α-acids. Flow cytometry analysis demonstrated that the expression of cells producing CD86, CD68, TSPO, MIP-1α, TNF-α, and IL-1β in microglia was increased in rTg4510 mice compared with wild-type mice. Furthermore, the expression of CD86- and MIP-1α-producing cells was reduced in rTg4510 mice administered with iso-α-acids. Moreover, the consumption of iso-α-acids reduced the levels of phosphorylated tau in the frontal cortex. Collectively, these results suggest that the consumption of iso-α-acids prevents the inflammation induced in tauopathy mice. Thus, iso-α-acids may help in preventing inflammation-related brain disorders.

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Surfactant protein A inhibits alveolar macrophage cytokine production by CD14-independent pathway

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00427.2002 ◽

2004 ◽

Vol 286 (1) ◽

pp. L129-L136 ◽

Cited By ~ 39

Author(s):

John F. Alcorn ◽

Jo Rae Wright

Keyword(s):

Alveolar Macrophages ◽

Cytokine Production ◽

Protein A ◽

Surfactant Protein ◽

Surfactant Protein A ◽

Null Mouse ◽

Mrna Levels ◽

Wild Type ◽

Independent Manner ◽

Tnf Α

The lung collectin surfactant protein A (SP-A) has both anti-inflammatory and prophagocytic activities. We and others previously showed that SP-A inhibits the macrophage production of tumor necrosis factor (TNF)-α stimulated by the gram-negative bacterial component LPS. We propose that SP-A decreases the production of proinflammatory cytokines by alveolar macrophages via a CD14-independent mechanism. SP-A inhibited LPS-simulated TNF-α production in rat and mouse macrophages in the presence and absence of serum (72% and 42% inhibition, respectively). In addition, SP-A inhibited LPS-induced mRNA levels for TNF-α, IL-1α, and IL-1β as well as NF-κB DNA binding activity. SP-A also diminished ultrapure LPS-stimulated TNF-α produced by wild-type and CD14-null mouse alveolar macrophages by 58% and 88%, respectively. Additionally, SP-A inhibited TNF-α stimulated by PMA in both wild-type and TLR4-mutant macrophages. These data suggest that SP-A inhibits inflammatory cytokine production in a CD14-independent manner and also by mechanisms independent of the LPS signaling pathway.

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