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Lethal inflammasome activation by a multidrug-resistant pathobiont upon antibiotic disruption of the microbiota.

Ayres JS, Trinidad NJ, Vance RE - Nat. Med. (2012)

Bottom Line: The mammalian intestine harbors a complex microbial community that provides numerous benefits to its host.In accordance with Koch's postulates, we found the E. coli pathobiont was sufficient to activate Naip5-Nlrc4 and cause disease when injected intravenously into unmanipulated mice.These findings reveal how sepsis-like disease can result from recognition of pathobionts by the innate immune system.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular & Cell Biology, Division of Immunology & Pathogenesis, University of California, Berkeley, USA. jayres@berkeley.edu

ABSTRACT
The mammalian intestine harbors a complex microbial community that provides numerous benefits to its host. However, the microbiota can also include potentially virulent species, termed pathobiont, which can cause disease when intestinal homeostasis is disrupted. The molecular mechanisms by which pathobionts cause disease remain poorly understood. Here we describe a sepsis-like disease that occurs upon gut injury in antibiotic-treated mice. Sepsis was associated with the systemic spread of a specific multidrug-resistant Escherichia coli pathobiont that expanded markedly in the microbiota of antibiotic-treated mice. Rapid sepsis-like death required a component of the innate immune system, the Naip5-Nlrc4 inflammasome. In accordance with Koch's postulates, we found the E. coli pathobiont was sufficient to activate Naip5-Nlrc4 and cause disease when injected intravenously into unmanipulated mice. These findings reveal how sepsis-like disease can result from recognition of pathobionts by the innate immune system.

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The Naip5-Nlrc4 inflammasome reduces host tolerance of a systemic E. coli infection(a) Survival of female wild-type and Naip5−/−Nlrc4−/− mutant mice infected with 5×108 live E. coli. P = 0.0001 by Log rank analysis. Wild-type (n = 9) and Naip5−/−Nlrc4−/− (n = 11).(b) Rectal temperature of female wild-type and Naip5−/−Nlrc4−/− mutant mice infected with 5×108 live E. coli. Wild-type (n = 9) and Naip5−/−Nlrc4−/− (n = 11). *** P = 0.0003 by Mann-Whitney test.(c) Intestinal pathology at 48 h post-infection of wild-type and Naip5−/−Nlrc4−/− mutant mice infected with 5×108 live E. coli.(d) Serum levels of BUN, CPK, ALT and AST female wild-type and Naip5−/−Nlrc4−/− mutant mice infected with 5×108 live E. coli. at 24 h post-infection. *P < 0.05 by Mann-Whitney test. Wild-type (n = 7) and Naip5−/−Nlrc4−/− (n = 6).(e) in vivo infection of Caspase-1−/− and Il-1β−/− female mutant mice. Survival was monitored and compared to infected wild-type female mice. Infectious dose was 5×108 live E. coli O21:H+. For Caspase-1−/− P = 0.0025 and for Il-1β−/− P < 0.0001 by Log rank analysis. Wild-type (n = 9), Caspase-1−/− (n = 6) and Il-1β−/− (n = 12).(f) Wild-type male and female mice were treated with AVNM for 7 d and then given AVNM+5% DSS. At 1, 24 and 48 h post DSS treatment initiation, mice were injected i.p. with 100 μg of α-IL-1R (n = 13) or control IgG antibody (n = 8) and survival was monitored. P = 0.0016 by Log rank analysis(g) Wild-type and Naip5−/−Nlrc4−/− mutant female mice were infected with 5×108 live E. coli. At 24 and 48 h post infection, tissues were harvested, homogenized and analyzed for levels of E. coli colonization. Data were analyzed by Student t-test.
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Figure 6: The Naip5-Nlrc4 inflammasome reduces host tolerance of a systemic E. coli infection(a) Survival of female wild-type and Naip5−/−Nlrc4−/− mutant mice infected with 5×108 live E. coli. P = 0.0001 by Log rank analysis. Wild-type (n = 9) and Naip5−/−Nlrc4−/− (n = 11).(b) Rectal temperature of female wild-type and Naip5−/−Nlrc4−/− mutant mice infected with 5×108 live E. coli. Wild-type (n = 9) and Naip5−/−Nlrc4−/− (n = 11). *** P = 0.0003 by Mann-Whitney test.(c) Intestinal pathology at 48 h post-infection of wild-type and Naip5−/−Nlrc4−/− mutant mice infected with 5×108 live E. coli.(d) Serum levels of BUN, CPK, ALT and AST female wild-type and Naip5−/−Nlrc4−/− mutant mice infected with 5×108 live E. coli. at 24 h post-infection. *P < 0.05 by Mann-Whitney test. Wild-type (n = 7) and Naip5−/−Nlrc4−/− (n = 6).(e) in vivo infection of Caspase-1−/− and Il-1β−/− female mutant mice. Survival was monitored and compared to infected wild-type female mice. Infectious dose was 5×108 live E. coli O21:H+. For Caspase-1−/− P = 0.0025 and for Il-1β−/− P < 0.0001 by Log rank analysis. Wild-type (n = 9), Caspase-1−/− (n = 6) and Il-1β−/− (n = 12).(f) Wild-type male and female mice were treated with AVNM for 7 d and then given AVNM+5% DSS. At 1, 24 and 48 h post DSS treatment initiation, mice were injected i.p. with 100 μg of α-IL-1R (n = 13) or control IgG antibody (n = 8) and survival was monitored. P = 0.0016 by Log rank analysis(g) Wild-type and Naip5−/−Nlrc4−/− mutant female mice were infected with 5×108 live E. coli. At 24 and 48 h post infection, tissues were harvested, homogenized and analyzed for levels of E. coli colonization. Data were analyzed by Student t-test.

Mentions: To address Koch's Postulates we infected wild-type and Nlrc4−/−Naip5−/− mice intravenously with E. coli-O21:H+. Systemic E. coli-O21:H+ infection was significantly less lethal in the absence of Naip5-Nlrc4 function (P = 0.0001) (Fig. 6a and Supplemental Fig. 7a, b). The absence of Naip5-Nlrc4 function also alleviated the pathologies associated with E. coli-O21:H+ infection (Fig. 6b – d). Furthermore, E. coli-O21:H+ infection was attenuated in Caspase1−/− and Il-1β−/− mice (Fig. 6e and Supplementary Fig. 7c, d). Additionally, systemic administration of anti-IL-1 receptor antibody protected mice from disease AVNM+DSS-induced disease (Fig. 6f). Thus, the absence of IL-1β is sufficient to protect mice from a systemic inflammatory response induced by a systemic E. coli-O21:H+ infection (Fig. 6e and Supplementary Fig. 7d). Taken together, our data clearly demonstrate that Naip5-Nlrc4 inflammasome signaling through IL-1β in response to a systemic E. coli-O21:H+ infection leads to sepsis.


Lethal inflammasome activation by a multidrug-resistant pathobiont upon antibiotic disruption of the microbiota.

Ayres JS, Trinidad NJ, Vance RE - Nat. Med. (2012)

The Naip5-Nlrc4 inflammasome reduces host tolerance of a systemic E. coli infection(a) Survival of female wild-type and Naip5−/−Nlrc4−/− mutant mice infected with 5×108 live E. coli. P = 0.0001 by Log rank analysis. Wild-type (n = 9) and Naip5−/−Nlrc4−/− (n = 11).(b) Rectal temperature of female wild-type and Naip5−/−Nlrc4−/− mutant mice infected with 5×108 live E. coli. Wild-type (n = 9) and Naip5−/−Nlrc4−/− (n = 11). *** P = 0.0003 by Mann-Whitney test.(c) Intestinal pathology at 48 h post-infection of wild-type and Naip5−/−Nlrc4−/− mutant mice infected with 5×108 live E. coli.(d) Serum levels of BUN, CPK, ALT and AST female wild-type and Naip5−/−Nlrc4−/− mutant mice infected with 5×108 live E. coli. at 24 h post-infection. *P < 0.05 by Mann-Whitney test. Wild-type (n = 7) and Naip5−/−Nlrc4−/− (n = 6).(e) in vivo infection of Caspase-1−/− and Il-1β−/− female mutant mice. Survival was monitored and compared to infected wild-type female mice. Infectious dose was 5×108 live E. coli O21:H+. For Caspase-1−/− P = 0.0025 and for Il-1β−/− P < 0.0001 by Log rank analysis. Wild-type (n = 9), Caspase-1−/− (n = 6) and Il-1β−/− (n = 12).(f) Wild-type male and female mice were treated with AVNM for 7 d and then given AVNM+5% DSS. At 1, 24 and 48 h post DSS treatment initiation, mice were injected i.p. with 100 μg of α-IL-1R (n = 13) or control IgG antibody (n = 8) and survival was monitored. P = 0.0016 by Log rank analysis(g) Wild-type and Naip5−/−Nlrc4−/− mutant female mice were infected with 5×108 live E. coli. At 24 and 48 h post infection, tissues were harvested, homogenized and analyzed for levels of E. coli colonization. Data were analyzed by Student t-test.
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Figure 6: The Naip5-Nlrc4 inflammasome reduces host tolerance of a systemic E. coli infection(a) Survival of female wild-type and Naip5−/−Nlrc4−/− mutant mice infected with 5×108 live E. coli. P = 0.0001 by Log rank analysis. Wild-type (n = 9) and Naip5−/−Nlrc4−/− (n = 11).(b) Rectal temperature of female wild-type and Naip5−/−Nlrc4−/− mutant mice infected with 5×108 live E. coli. Wild-type (n = 9) and Naip5−/−Nlrc4−/− (n = 11). *** P = 0.0003 by Mann-Whitney test.(c) Intestinal pathology at 48 h post-infection of wild-type and Naip5−/−Nlrc4−/− mutant mice infected with 5×108 live E. coli.(d) Serum levels of BUN, CPK, ALT and AST female wild-type and Naip5−/−Nlrc4−/− mutant mice infected with 5×108 live E. coli. at 24 h post-infection. *P < 0.05 by Mann-Whitney test. Wild-type (n = 7) and Naip5−/−Nlrc4−/− (n = 6).(e) in vivo infection of Caspase-1−/− and Il-1β−/− female mutant mice. Survival was monitored and compared to infected wild-type female mice. Infectious dose was 5×108 live E. coli O21:H+. For Caspase-1−/− P = 0.0025 and for Il-1β−/− P < 0.0001 by Log rank analysis. Wild-type (n = 9), Caspase-1−/− (n = 6) and Il-1β−/− (n = 12).(f) Wild-type male and female mice were treated with AVNM for 7 d and then given AVNM+5% DSS. At 1, 24 and 48 h post DSS treatment initiation, mice were injected i.p. with 100 μg of α-IL-1R (n = 13) or control IgG antibody (n = 8) and survival was monitored. P = 0.0016 by Log rank analysis(g) Wild-type and Naip5−/−Nlrc4−/− mutant female mice were infected with 5×108 live E. coli. At 24 and 48 h post infection, tissues were harvested, homogenized and analyzed for levels of E. coli colonization. Data were analyzed by Student t-test.
Mentions: To address Koch's Postulates we infected wild-type and Nlrc4−/−Naip5−/− mice intravenously with E. coli-O21:H+. Systemic E. coli-O21:H+ infection was significantly less lethal in the absence of Naip5-Nlrc4 function (P = 0.0001) (Fig. 6a and Supplemental Fig. 7a, b). The absence of Naip5-Nlrc4 function also alleviated the pathologies associated with E. coli-O21:H+ infection (Fig. 6b – d). Furthermore, E. coli-O21:H+ infection was attenuated in Caspase1−/− and Il-1β−/− mice (Fig. 6e and Supplementary Fig. 7c, d). Additionally, systemic administration of anti-IL-1 receptor antibody protected mice from disease AVNM+DSS-induced disease (Fig. 6f). Thus, the absence of IL-1β is sufficient to protect mice from a systemic inflammatory response induced by a systemic E. coli-O21:H+ infection (Fig. 6e and Supplementary Fig. 7d). Taken together, our data clearly demonstrate that Naip5-Nlrc4 inflammasome signaling through IL-1β in response to a systemic E. coli-O21:H+ infection leads to sepsis.

Bottom Line: The mammalian intestine harbors a complex microbial community that provides numerous benefits to its host.In accordance with Koch's postulates, we found the E. coli pathobiont was sufficient to activate Naip5-Nlrc4 and cause disease when injected intravenously into unmanipulated mice.These findings reveal how sepsis-like disease can result from recognition of pathobionts by the innate immune system.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular & Cell Biology, Division of Immunology & Pathogenesis, University of California, Berkeley, USA. jayres@berkeley.edu

ABSTRACT
The mammalian intestine harbors a complex microbial community that provides numerous benefits to its host. However, the microbiota can also include potentially virulent species, termed pathobiont, which can cause disease when intestinal homeostasis is disrupted. The molecular mechanisms by which pathobionts cause disease remain poorly understood. Here we describe a sepsis-like disease that occurs upon gut injury in antibiotic-treated mice. Sepsis was associated with the systemic spread of a specific multidrug-resistant Escherichia coli pathobiont that expanded markedly in the microbiota of antibiotic-treated mice. Rapid sepsis-like death required a component of the innate immune system, the Naip5-Nlrc4 inflammasome. In accordance with Koch's postulates, we found the E. coli pathobiont was sufficient to activate Naip5-Nlrc4 and cause disease when injected intravenously into unmanipulated mice. These findings reveal how sepsis-like disease can result from recognition of pathobionts by the innate immune system.

Show MeSH
Related in: MedlinePlus