Limits...
The retinoic acid-producing capacity of gut dendritic cells and macrophages is reduced during persistent T. muris infection.

Hurst RJ, Else KJ - Parasite Immunol. (2013)

Bottom Line: Vitamin A and its active metabolite retinoic acid are strongly linked with the modulation of gut immune responses.Further, during an on-going T. muris infection, ALDH expression is repressed from uninfected levels and only recovers to normal levels following expulsion of the parasite.These results suggest that local regulation of cellular levels of retinoic acid is an important component of infection-driven inflammation.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Life Sciences, The University of Manchester, Manchester, UK. rebecca.hurst@manchester.ac.uk

Show MeSH

Related in: MedlinePlus

Aldehyde dehydrogenase (ALDH) activity is locally decreased during high-dose T. muris infection. Lamina propria leukocytes (LPLs) were isolated from the large intestines of susceptible AKR mice and resistant C57BL/6 mice at weekly intervals throughout the course of T. muris infection. (a) Gating strategy for 7AAD-CD45+MHCII+CD103-F4/80+CD11b+ macrophages and 7AAD-CD45+MHCII+CD103+F4/80-CD11c+ dendritic cells that were positively stained for ALDH activity. The blue line represents ALDH+ cells and the red line shows ALDH+ activity incubated with the retinaldehyde dehydrogenase inhibitor, diethylaminobenzaldehyde (DEAB), as a negative control. Percentage of MHCII+CD103-F4/80+CD11b+ macrophages or MHCII+CD103+F4/80-CD11c+ dendritic cells that have ALDH activity at each stage of infection in AKR mice given a high-dose (chronic) infection (b), C57BL/6 mice given a high-dose (acute) infection (c) and C57BL/6 mice given a low-dose (chronic) infection (d). Graphs show means + SEM. (n = 3–4) *P < 0·05, **P < 0·01, ***P < 0·001, compared to naïve levels, unless otherwise shown. Data is representative of two independent experiments, repeated at key time points.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3757314&req=5

fig01: Aldehyde dehydrogenase (ALDH) activity is locally decreased during high-dose T. muris infection. Lamina propria leukocytes (LPLs) were isolated from the large intestines of susceptible AKR mice and resistant C57BL/6 mice at weekly intervals throughout the course of T. muris infection. (a) Gating strategy for 7AAD-CD45+MHCII+CD103-F4/80+CD11b+ macrophages and 7AAD-CD45+MHCII+CD103+F4/80-CD11c+ dendritic cells that were positively stained for ALDH activity. The blue line represents ALDH+ cells and the red line shows ALDH+ activity incubated with the retinaldehyde dehydrogenase inhibitor, diethylaminobenzaldehyde (DEAB), as a negative control. Percentage of MHCII+CD103-F4/80+CD11b+ macrophages or MHCII+CD103+F4/80-CD11c+ dendritic cells that have ALDH activity at each stage of infection in AKR mice given a high-dose (chronic) infection (b), C57BL/6 mice given a high-dose (acute) infection (c) and C57BL/6 mice given a low-dose (chronic) infection (d). Graphs show means + SEM. (n = 3–4) *P < 0·05, **P < 0·01, ***P < 0·001, compared to naïve levels, unless otherwise shown. Data is representative of two independent experiments, repeated at key time points.

Mentions: To establish whether the production of retinoic acid changes over the course of an acute and/or chronic T. muris infection, the ALDEFLUOR assay was used to measure the expression of aldehyde dehydrogenases (ALDH) in large intestinal macrophages and dendritic cells (DCs). ALDH enzymes are responsible for the production of retinoic acid from its precursors, and their expression is tightly regulated 13. Acute T. muris infection was modelled in C57BL/6 mice given a high-dose infection (expulsion complete by day 21 p.i.). Chronic infection was modelled in both AKR mice given a high-dose infection and C57BL/6 mice given a low-dose infection. Thus, lamina propria leucocytes were isolated from the colons of chronically infected AKR mice, chronically infected C57BL/6 mice and acutely infected C57BL/6 mice at 7-day intervals and FACS stained. The phenotyping of gut macrophages and DCs is complex and controversial 18, 19. In this study, macrophages were defined as 7AAD-CD45+MHCII+CD103-F4/80+CD11b+ cells and DCs were defined as 7AAD-CD45+MHCII+CD103+F4/80-CD11c+ cells (Fig. 1a). Percentages of macrophage and DC populations expressing ALDH were analysed rather than total numbers of cells, as is it impossible to determine total numbers of cells given the way cells were extracted from the gut.


The retinoic acid-producing capacity of gut dendritic cells and macrophages is reduced during persistent T. muris infection.

Hurst RJ, Else KJ - Parasite Immunol. (2013)

Aldehyde dehydrogenase (ALDH) activity is locally decreased during high-dose T. muris infection. Lamina propria leukocytes (LPLs) were isolated from the large intestines of susceptible AKR mice and resistant C57BL/6 mice at weekly intervals throughout the course of T. muris infection. (a) Gating strategy for 7AAD-CD45+MHCII+CD103-F4/80+CD11b+ macrophages and 7AAD-CD45+MHCII+CD103+F4/80-CD11c+ dendritic cells that were positively stained for ALDH activity. The blue line represents ALDH+ cells and the red line shows ALDH+ activity incubated with the retinaldehyde dehydrogenase inhibitor, diethylaminobenzaldehyde (DEAB), as a negative control. Percentage of MHCII+CD103-F4/80+CD11b+ macrophages or MHCII+CD103+F4/80-CD11c+ dendritic cells that have ALDH activity at each stage of infection in AKR mice given a high-dose (chronic) infection (b), C57BL/6 mice given a high-dose (acute) infection (c) and C57BL/6 mice given a low-dose (chronic) infection (d). Graphs show means + SEM. (n = 3–4) *P < 0·05, **P < 0·01, ***P < 0·001, compared to naïve levels, unless otherwise shown. Data is representative of two independent experiments, repeated at key time points.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3757314&req=5

fig01: Aldehyde dehydrogenase (ALDH) activity is locally decreased during high-dose T. muris infection. Lamina propria leukocytes (LPLs) were isolated from the large intestines of susceptible AKR mice and resistant C57BL/6 mice at weekly intervals throughout the course of T. muris infection. (a) Gating strategy for 7AAD-CD45+MHCII+CD103-F4/80+CD11b+ macrophages and 7AAD-CD45+MHCII+CD103+F4/80-CD11c+ dendritic cells that were positively stained for ALDH activity. The blue line represents ALDH+ cells and the red line shows ALDH+ activity incubated with the retinaldehyde dehydrogenase inhibitor, diethylaminobenzaldehyde (DEAB), as a negative control. Percentage of MHCII+CD103-F4/80+CD11b+ macrophages or MHCII+CD103+F4/80-CD11c+ dendritic cells that have ALDH activity at each stage of infection in AKR mice given a high-dose (chronic) infection (b), C57BL/6 mice given a high-dose (acute) infection (c) and C57BL/6 mice given a low-dose (chronic) infection (d). Graphs show means + SEM. (n = 3–4) *P < 0·05, **P < 0·01, ***P < 0·001, compared to naïve levels, unless otherwise shown. Data is representative of two independent experiments, repeated at key time points.
Mentions: To establish whether the production of retinoic acid changes over the course of an acute and/or chronic T. muris infection, the ALDEFLUOR assay was used to measure the expression of aldehyde dehydrogenases (ALDH) in large intestinal macrophages and dendritic cells (DCs). ALDH enzymes are responsible for the production of retinoic acid from its precursors, and their expression is tightly regulated 13. Acute T. muris infection was modelled in C57BL/6 mice given a high-dose infection (expulsion complete by day 21 p.i.). Chronic infection was modelled in both AKR mice given a high-dose infection and C57BL/6 mice given a low-dose infection. Thus, lamina propria leucocytes were isolated from the colons of chronically infected AKR mice, chronically infected C57BL/6 mice and acutely infected C57BL/6 mice at 7-day intervals and FACS stained. The phenotyping of gut macrophages and DCs is complex and controversial 18, 19. In this study, macrophages were defined as 7AAD-CD45+MHCII+CD103-F4/80+CD11b+ cells and DCs were defined as 7AAD-CD45+MHCII+CD103+F4/80-CD11c+ cells (Fig. 1a). Percentages of macrophage and DC populations expressing ALDH were analysed rather than total numbers of cells, as is it impossible to determine total numbers of cells given the way cells were extracted from the gut.

Bottom Line: Vitamin A and its active metabolite retinoic acid are strongly linked with the modulation of gut immune responses.Further, during an on-going T. muris infection, ALDH expression is repressed from uninfected levels and only recovers to normal levels following expulsion of the parasite.These results suggest that local regulation of cellular levels of retinoic acid is an important component of infection-driven inflammation.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Life Sciences, The University of Manchester, Manchester, UK. rebecca.hurst@manchester.ac.uk

Show MeSH
Related in: MedlinePlus