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Cited by 319Wound Healing and TreatmentsInflammasome and immune disordersDiabetic Foot Ulcer Assessment and Management

The DOI matches its Crossref record; 50 of the 54 references it cites were found in a registry or an index; none of the 62 sources its claims cite is checked for support yet.

Sustained Inflammasome Activity in Macrophages Impairs Wound Healing in Type 2 Diabetic Humans and Mice

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Mirza, Rita E., Fang, Milie M., Weinheimer-Haus, Eileen M., Ennis, William J., Koh, Timothy J.·2014·Diabetes
DOI 10.2337/db13-0927PMC PMC3931398
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Abstract

The hypothesis of this study was that sustained activity of the Nod-like receptor protein (NLRP)-3 inflammasome in wounds of diabetic humans and mice contributes to the persistent inflammatory response and impaired healing characteristic of these wounds. Macrophages (Mp) isolated from wounds on diabetic humans and db/db mice exhibited sustained inflammasome activity associated with low level of expression of endogenous inflammasome inhibitors. Soluble factors in the biochemical milieu of these wounds are sufficient to activate the inflammasome, as wound-conditioned medium activates caspase-1 and induces release of interleukin (IL)-1β and IL-18 in cultured Mp via a reactive oxygen species–mediated pathway. Importantly, inhibiting inflammasome activity in wounds of db/db mice using topical application of pharmacological inhibitors improved healing of these wounds, induced a switch from proinflammatory to healing-associated Mp phenotypes, and increased levels of prohealing growth factors. Furthermore, data generated from bone marrow–transfer experiments from NLRP-3 or caspase-1 knockout to db/db mice indicated that blocking inflammasome activity in bone marrow cells is sufficient to improve healing. Our findings indicate that sustained inflammasome activity in wound Mp contributes to impaired early healing responses of diabetic wounds and that the inflammasome may represent a new therapeutic target for improving healing in diabetic individuals.

Overview

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Written from the paper’s full text.

TL;DR

Sustained NLRP-3 inflammasome activity in wound macrophages from type 2 diabetic humans and db/db mice contributes to persistent inflammation and impaired healing. Blocking inflammasome activity pharmacologically or via NLRP-3/caspase-1–null bone marrow transfer improved early wound healing and shifted macrophages toward a prohealing phenotype.

Key findings

  • Macrophages from chronic wounds of diabetic humans and db/db mice showed sustained inflammasome activity, with high NLRP-3, caspase-1, IL-1β, and IL-18, but low expression of endogenous inhibitors PI-9 and caspase-12. Active caspase-1 was detected in 9.9 ± 1.4% of db/db wound macrophages versus 4.8 ± 1.1% of db/+ wound macrophages.
  • Wound-conditioned medium activated caspase-1 and induced IL-1β/IL-18 release in cultured human and mouse macrophages via an ROS-mediated pathway; active caspase-1 was detected in 10.5 ± 1.3% of conditioned-medium–stimulated cells versus 2.9 ± 0.7% of nonstimulated controls.
  • Topical glyburide (200 μmol/L) or YVAD (20 μmol/L) in db/db wounds accelerated re-epithelialization, increased granulation tissue, reduced wound IL-1β/IL-18, increased IGF-1 and TGF-β, and shifted wound macrophage expression away from proinflammatory cytokines toward IGF-1, TGF-β, IL-10, and CD206.
  • Bone marrow transfer from NLRP-3– or caspase-1–null mice to db/db mice improved re-epithelialization and granulation tissue formation and reduced wound IL-1β and IL-18, indicating bone marrow–derived inflammasome activity is sufficient to impair healing.

Methods

  • Human chronic wound biopsies were collected from five type 2 diabetic patients (2 male, 3 female) with nonhealing sacral or lower-limb wounds lasting at least 3 months; mouse experiments used db/db, db/+, C57Bl/6 wild-type, NLRP-3 knockout, caspase-1 knockout, and IL-1R1 knockout mice.
  • Excisional wounds were made with an 8-mm biopsy punch; treatments were applied topically every other day starting 3 days postinjury in F-127 pluronic gel, and healing was assessed on day 10 by re-epithelialization, granulation tissue, collagen, CD31, and α-smooth-muscle actin staining.
  • Macrophages were isolated by magnetic depletion and CD11b selection; inflammasome activity was assessed by real-time PCR, ELISA, flow cytometry for active caspase-1, immunofluorescence, and in vitro stimulation with wound-conditioned medium plus inhibitors; data were analyzed by ANOVA or ANOVA on ranks with Student-Newman-Keuls post hoc tests, P ≤ 0.05.

Limitations

  • Stated: caspase-1–null mice were also deficient in caspase-11, so bone marrow–transfer experiments could not distinguish the roles of these caspases in impaired healing.
  • Stated: topical glyburide and YVAD could block inflammasome activity in keratinocytes as well as macrophages, although the authors note macrophages were the dominant IL-1β producers and bone marrow transfer was sufficient to reduce wound IL-1β/IL-18.
  • Evident: the human component is limited to five wound biopsies with no human therapeutic intervention, and macrophage phenotype changes after YVAD treatment were not measured.

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Crossref · 10.2337/db13-0927

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Figures

Figure 1 Mp from chronic wounds of diabetic patients express components of the NLRP-3 inflammasome. A–F: Mp isolated from chronic wound biopsies and expression of IL-1β, IL-18, NLRP-3, caspase-1, PI-9, and caspase-12 assessed by real-time PCR. For comparison, blood-derived Mp from healthy volunteers were either left nonstimulated (Non) or stimulated with TNF-α and IFN-γ (classical) and gene expression was assessed along wound Mp. G–I: Wound biopsy cryosections immunostained for caspase-1 and the Mp marker CD68; scale bar = 100 μm. For all graphs, bars = mean ± SD, n = 5. Data compared between groups using ANOVA on ranks. *Mean value significantly different from that for nonstimulated controls; **mean value significantly different from that for classically activated cells; P < 0.05. Diff, difference.
Figure 1 Mp from chronic wounds of diabetic patients express components of the NLRP-3 inflammasome. A–F: Mp isolated from chronic wound biopsies and expression of IL-1β, IL-18, NLRP-3, caspase-1, PI-9, and caspase-12 assessed by real-time PCR. For comparison, blood-derived Mp from healthy volunteers were either left nonstimulated (Non) or stimulated with TNF-α and IFN-γ (classical) and gene expression was assessed along wound Mp. G–I: Wound biopsy cryosections immunostained for caspase-1 and the Mp marker CD68; scale bar = 100 μm. For all graphs, bars = mean ± SD, n = 5. Data compared between groups using ANOVA on ranks. *Mean value significantly different from that for nonstimulated controls; **mean value significantly different from that for classically activated cells; P < 0.05. Diff, difference.CC BY-NC-ND · PubMed Central
Figure 2 Mp exhibit sustained inflammasome activity in wounds of diabetic mice. A and B: Mp isolated from wounds of nondiabetic (db/+) and diabetic (db/db) mice on days 5 and 10 postinjury and expression of IL-1β and IL-18 assessed by real-time PCR. C and D: Neutrophils (Ly6G+)/B cells (CD19+)/T cells (CD3+) (combined NBT+ cells), Mp (NBT−CD11b+ cells), and remaining cells (NBT−CD11b− cells) isolated from day 5 db/+ and db/db wounds and incubated overnight; release of IL-1β and IL-18 measured using ELISA. E and F: Mp (NBT−CD11b+ cells) isolated from day 5 and 10 db/+ and db/db wounds and incubated overnight; release of IL-1β and IL-18 measured using ELISA. G and H: Representative flow cytograms of active caspase-1 in Mp (NBT−CD11b+ cells) isolated from day 10 db/+ and db/db wounds. I-L: Mp isolated from db/+ and db/db wounds on days 5 and 10 postinjury and expression of NLRP-3, caspase-1, PI-9, and caspase-12 assessed by real-time PCR. For all graphs, bars = mean ± SD, n = 6–8. Data compared between groups using ANOVA. *Mean value significantly different from that for same strain on day 5 postinjury; **mean value for db/db mice significantly different from that for db/+ mice at same time point; #mean value significantly different from those for other cell types; P < 0.05. Diff, difference.
Figure 2 Mp exhibit sustained inflammasome activity in wounds of diabetic mice. A and B: Mp isolated from wounds of nondiabetic (db/+) and diabetic (db/db) mice on days 5 and 10 postinjury and expression of IL-1β and IL-18 assessed by real-time PCR. C and D: Neutrophils (Ly6G+)/B cells (CD19+)/T cells (CD3+) (combined NBT+ cells), Mp (NBT−CD11b+ cells), and remaining cells (NBT−CD11b− cells) isolated from day 5 db/+ and db/db wounds and incubated overnight; release of IL-1β and IL-18 measured using ELISA. E and F: Mp (NBT−CD11b+ cells) isolated from day 5 and 10 db/+ and db/db wounds and incubated overnight; release of IL-1β and IL-18 measured using ELISA. G and H: Representative flow cytograms of active caspase-1 in Mp (NBT−CD11b+ cells) isolated from day 10 db/+ and db/db wounds. I-L: Mp isolated from db/+ and db/db wounds on days 5 and 10 postinjury and expression of NLRP-3, caspase-1, PI-9, and caspase-12 assessed by real-time PCR. For all graphs, bars = mean ± SD, n = 6–8. Data compared between groups using ANOVA. *Mean value significantly different from that for same strain on day 5 postinjury; **mean value for db/db mice significantly different from that for db/+ mice at same time point; #mean value significantly different from those for other cell types; P < 0.05. Diff, difference.CC BY-NC-ND · PubMed Central
Figure 3 Wound-conditioned medium activates the inflammasome in both human and mouse Mp in vitro. A and B: Blood-derived Mp from healthy human volunteers either left nonstimulated (N) or stimulated with chronic wound–conditioned medium (CM) along with vehicle (V), the caspase-1 inhibitor YVAD (Y) (20 μmol/L), or the inflammasome inhibitor glyburide (G) (200 μmol/L) and release of IL-1β and IL-18 measured by ELISA. C and D: Representative flow cytograms of active caspase-1 in human blood–derived Mp, Mp either left nonstimulated or stimulated with chronic wound–conditioned medium. E and F: Bone marrow–derived Mp from wild-type (C57BL/6) mice either left nonstimulated or stimulated with day 10 db/db wound-conditioned medium along with vehicle or the same inhibitors as used for human Mp and release of IL-1β and IL-18 measured by ELISA. G and H: Bone marrow–derived Mp from wild-type (WT), caspase-1 (Casp1), and NLRP-3 knockout (ko) mice left nonstimulated (Non), stimulated with TNF-α and IFN-γ (20 ng/mL each) (CA), or stimulated with day 10 db/db wound-conditioned medium (CM). For all graphs, bars = mean ± SD, n = 5–6 in two separate experiments. Data compared between groups using ANOVA on ranks. *Mean value significantly different from that for nonstimulated controls; **mean value significantly different from that for wound-conditioned medium + vehicle-treated cells; #mean value significantly different from that for nonstimulated controls; ##mean value significantly different from that for wound-conditioned medium–treated wild-type Mp; P < 0.05. FSC, forward scatter.
Figure 3 Wound-conditioned medium activates the inflammasome in both human and mouse Mp in vitro. A and B: Blood-derived Mp from healthy human volunteers either left nonstimulated (N) or stimulated with chronic wound–conditioned medium (CM) along with vehicle (V), the caspase-1 inhibitor YVAD (Y) (20 μmol/L), or the inflammasome inhibitor glyburide (G) (200 μmol/L) and release of IL-1β and IL-18 measured by ELISA. C and D: Representative flow cytograms of active caspase-1 in human blood–derived Mp, Mp either left nonstimulated or stimulated with chronic wound–conditioned medium. E and F: Bone marrow–derived Mp from wild-type (C57BL/6) mice either left nonstimulated or stimulated with day 10 db/db wound-conditioned medium along with vehicle or the same inhibitors as used for human Mp and release of IL-1β and IL-18 measured by ELISA. G and H: Bone marrow–derived Mp from wild-type (WT), caspase-1 (Casp1), and NLRP-3 knockout (ko) mice left nonstimulated (Non), stimulated with TNF-α and IFN-γ (20 ng/mL each) (CA), or stimulated with day 10 db/db wound-conditioned medium (CM). For all graphs, bars = mean ± SD, n = 5–6 in two separate experiments. Data compared between groups using ANOVA on ranks. *Mean value significantly different from that for nonstimulated controls; **mean value significantly different from that for wound-conditioned medium + vehicle-treated cells; #mean value significantly different from that for nonstimulated controls; ##mean value significantly different from that for wound-conditioned medium–treated wild-type Mp; P < 0.05. FSC, forward scatter.CC BY-NC-ND · PubMed Central
Figure 4 ROS inhibitors block conditioned medium–induced inflammasome activity in cultured Mp. A: Bone marrow–derived Mp from wild-type mice were cultured with wound-conditioned medium (CM) of day 5 or 10 wounds from nondiabetic db/+ or diabetic db/db mice, and ROS generation was measured using DCF-DA and flow cytometry. DCF fluorescence measured as the difference in median fluorescence intensity (MFI) between wound-conditioned medium–treated cells and nonstimulated controls. B–D: Bone marrow–derived Mp from wild-type mice treated with day 10 db/db wound-conditioned medium along with vehicle (V), NAC (N) (25 mmol/L), or DPI (D) (25 μmol/L); ROS measured as change in median fluorescence intensity and IL-1β, and IL-18 release measured using ELISA. For all graphs, bars = mean ± SD, n = 6 in two independent experiments. Data compared between groups using ANOVA on ranks. *Mean value significantly different from that for wound-conditioned medium of same strain on day 5 postinjury; **mean value for db/db CM significantly different from that for db/+ wound-conditioned medium at same time point; #mean value significantly different from that for nonstimulated controls; ##mean value significantly different from that for wound-conditioned medium + vehicle-treated samples; P < 0.05.
Figure 4 ROS inhibitors block conditioned medium–induced inflammasome activity in cultured Mp. A: Bone marrow–derived Mp from wild-type mice were cultured with wound-conditioned medium (CM) of day 5 or 10 wounds from nondiabetic db/+ or diabetic db/db mice, and ROS generation was measured using DCF-DA and flow cytometry. DCF fluorescence measured as the difference in median fluorescence intensity (MFI) between wound-conditioned medium–treated cells and nonstimulated controls. B–D: Bone marrow–derived Mp from wild-type mice treated with day 10 db/db wound-conditioned medium along with vehicle (V), NAC (N) (25 mmol/L), or DPI (D) (25 μmol/L); ROS measured as change in median fluorescence intensity and IL-1β, and IL-18 release measured using ELISA. For all graphs, bars = mean ± SD, n = 6 in two independent experiments. Data compared between groups using ANOVA on ranks. *Mean value significantly different from that for wound-conditioned medium of same strain on day 5 postinjury; **mean value for db/db CM significantly different from that for db/+ wound-conditioned medium at same time point; #mean value significantly different from that for nonstimulated controls; ##mean value significantly different from that for wound-conditioned medium + vehicle-treated samples; P < 0.05.CC BY-NC-ND · PubMed Central
Figure 5 Blocking IL-1β signaling blunts conditioned medium–induced inflammasome activity in vitro. A–F: Bone marrow–derived Mp from wild-type (WT) mice either left nonstimulated (Non) or stimulated with day 10 db/db wound-conditioned medium (CM) along with control IgG or IL-1β blocking antibody (IL1ab), and expression of IL-1β, IL-18, PI-9, and caspase-12 measured by real-time PCR. G and H: Bone marrow–derived Mp from wild-type mice either left nonstimulated or treated with day 10 db/db wound CM along with control IgG or IL-1β blocking antibody and IL-1β and IL-18 release measured using ELISA. I–N: Bone marrow–derived Mp from WT and IL-1R1 knockout (ko) mice stimulated with day 10 db/db wound CM and expression of IL-1β, IL-18, PI-9, and caspase-12 measured by real-time PCR. O and P: Bone marrow–derived Mp from WT and IL-1R1ko mice stimulated with day 10 db/db CM and IL-1β and IL-18 release measured using ELISA. For all graphs, bars = mean ± SD, n = 5–6 in two independent experiments. Data compared between groups using ANOVA on ranks. *Mean value significantly different from that for nonstimulated controls; **mean value significantly different from that for wound-conditioned medium + IgG-treated samples; #mean value significantly different from that for nonstimulated controls; ##mean value significantly different from that for wound-conditioned medium–treated wild-type Mp at same time point; P < 0.05. Diff, difference.
Figure 5 Blocking IL-1β signaling blunts conditioned medium–induced inflammasome activity in vitro. A–F: Bone marrow–derived Mp from wild-type (WT) mice either left nonstimulated (Non) or stimulated with day 10 db/db wound-conditioned medium (CM) along with control IgG or IL-1β blocking antibody (IL1ab), and expression of IL-1β, IL-18, PI-9, and caspase-12 measured by real-time PCR. G and H: Bone marrow–derived Mp from wild-type mice either left nonstimulated or treated with day 10 db/db wound CM along with control IgG or IL-1β blocking antibody and IL-1β and IL-18 release measured using ELISA. I–N: Bone marrow–derived Mp from WT and IL-1R1 knockout (ko) mice stimulated with day 10 db/db wound CM and expression of IL-1β, IL-18, PI-9, and caspase-12 measured by real-time PCR. O and P: Bone marrow–derived Mp from WT and IL-1R1ko mice stimulated with day 10 db/db CM and IL-1β and IL-18 release measured using ELISA. For all graphs, bars = mean ± SD, n = 5–6 in two independent experiments. Data compared between groups using ANOVA on ranks. *Mean value significantly different from that for nonstimulated controls; **mean value significantly different from that for wound-conditioned medium + IgG-treated samples; #mean value significantly different from that for nonstimulated controls; ##mean value significantly different from that for wound-conditioned medium–treated wild-type Mp at same time point; P < 0.05. Diff, difference.CC BY-NC-ND · PubMed Central
Figure 6 Blocking inflammasome activity downregulates the proinflammatory wound environment, upregulates a prohealing environment, and improves healing in diabetic mice. A and B: Excisional wounds in db/db mice whose wounds were treated topically with DMSO vehicle or glyburide (Glyb) harvested on day 10 postinjury, sectioned and stained with hematoxylin-eosin. Note the increased re-epithelialization in glyburide-treated wounds. ep, epithelium; gt, granulation tissue. Arrows indicate ends of epithelial tongues, scale bar = 0.5 mm. C and D: Re-epithelialization and granulation tissue thickness measured in hematoxylin-eosin–stained cryosections of wounds in db/db mice treated with DMSO, glyburide, or acYVAD-cmk (YVAD). Trichrome staining measured as pixels stained blue for collagen (E) and CD31 staining measured as pixels stained for this endothelial cell marker (F). G–N: Levels of cytokines in wound homogenates measured using ELISA, including proinflammatory cytokines IL-1β, IL-18, TNF-α, and IL-6 and healing-associated cytokines IGF-1, TGF-β, IL-10, and VEGF. O–V: Mp isolated from wounds in db/db mice treated with DMSO or glyburide and expression of proinflammatory cytokines IL-1β, IL-18, TNF-α, and IL-6 and healing-associated cytokines IGF-1, TGF-β, IL-10, and CD206 assessed by real-time PCR. For comparison, bone marrow–derived Mp from wild-type mice were left nonstimulated (Con) and gene expression was assessed along with wound Mp. For all graphs, bars = mean ± SD, n = 6–8. Data compared between groups using ANOVA. *Mean value significantly different from that for DMSO-treated wounds; #mean value significantly different from that for nonstimulated in vitro control Mp; ##mean value significantly different from that for Mp isolated from DMSO-treated wounds; P < 0.05. Diff, difference.
Figure 6 Blocking inflammasome activity downregulates the proinflammatory wound environment, upregulates a prohealing environment, and improves healing in diabetic mice. A and B: Excisional wounds in db/db mice whose wounds were treated topically with DMSO vehicle or glyburide (Glyb) harvested on day 10 postinjury, sectioned and stained with hematoxylin-eosin. Note the increased re-epithelialization in glyburide-treated wounds. ep, epithelium; gt, granulation tissue. Arrows indicate ends of epithelial tongues, scale bar = 0.5 mm. C and D: Re-epithelialization and granulation tissue thickness measured in hematoxylin-eosin–stained cryosections of wounds in db/db mice treated with DMSO, glyburide, or acYVAD-cmk (YVAD). Trichrome staining measured as pixels stained blue for collagen (E) and CD31 staining measured as pixels stained for this endothelial cell marker (F). G–N: Levels of cytokines in wound homogenates measured using ELISA, including proinflammatory cytokines IL-1β, IL-18, TNF-α, and IL-6 and healing-associated cytokines IGF-1, TGF-β, IL-10, and VEGF. O–V: Mp isolated from wounds in db/db mice treated with DMSO or glyburide and expression of proinflammatory cytokines IL-1β, IL-18, TNF-α, and IL-6 and healing-associated cytokines IGF-1, TGF-β, IL-10, and CD206 assessed by real-time PCR. For comparison, bone marrow–derived Mp from wild-type mice were left nonstimulated (Con) and gene expression was assessed along with wound Mp. For all graphs, bars = mean ± SD, n = 6–8. Data compared between groups using ANOVA. *Mean value significantly different from that for DMSO-treated wounds; #mean value significantly different from that for nonstimulated in vitro control Mp; ##mean value significantly different from that for Mp isolated from DMSO-treated wounds; P < 0.05. Diff, difference.CC BY-NC-ND · PubMed Central
Figure 7 Bone marrow transfer from NLRP-3 and caspase-1–null mice to db/db mice is sufficient to downregulate the proinflammatory wound environment, upregulate a prohealing environment, and improve healing in diabetic mice. A and B: db/db Mice were subjected to lethal irradiation, and then bone marrow from wild-type (WT) or NLRP-3 (N3)–null mice was transferred 24 h later. Four weeks later, mice were subjected to excisional wounding, and wounds were harvested on day 10 postinjury, sectioned, and stained with hematoxylin-eosin. Note the increased re-epithelialization in db/db mice receiving NLRP-3 bone marrow. ep, epithelium; gt, granulation tissue. Arrows indicate ends of epithelial tongues, scale bar = 0.5 mm. C and D: Re-epithelialization and granulation tissue thickness measured in hematoxylin-eosin–stained cryosections of db/db mice receiving bone marrow from wild-type (WT-db) or NLRP-3–null (N3-db) or caspase-1–null (C1-db) mice. Trichrome staining measured as pixels stained blue for collagen (E) and CD31 staining measured as pixels stained for this endothelial cell marker (F). G–N: Levels of cytokines in wound homogenates measured using ELISA, including proinflammatory cytokines IL-1β, IL-18, TNF-α, and IL-6 and healing-associated cytokines IGF-1, TGF-β, IL-10, and VEGF. For all graphs, bars = mean ± SD, n = 6–8. Data compared between groups using ANOVA. *Mean value significantly different from that for mice receiving wild-type bone marrow; P < 0.05.
Figure 7 Bone marrow transfer from NLRP-3 and caspase-1–null mice to db/db mice is sufficient to downregulate the proinflammatory wound environment, upregulate a prohealing environment, and improve healing in diabetic mice. A and B: db/db Mice were subjected to lethal irradiation, and then bone marrow from wild-type (WT) or NLRP-3 (N3)–null mice was transferred 24 h later. Four weeks later, mice were subjected to excisional wounding, and wounds were harvested on day 10 postinjury, sectioned, and stained with hematoxylin-eosin. Note the increased re-epithelialization in db/db mice receiving NLRP-3 bone marrow. ep, epithelium; gt, granulation tissue. Arrows indicate ends of epithelial tongues, scale bar = 0.5 mm. C and D: Re-epithelialization and granulation tissue thickness measured in hematoxylin-eosin–stained cryosections of db/db mice receiving bone marrow from wild-type (WT-db) or NLRP-3–null (N3-db) or caspase-1–null (C1-db) mice. Trichrome staining measured as pixels stained blue for collagen (E) and CD31 staining measured as pixels stained for this endothelial cell marker (F). G–N: Levels of cytokines in wound homogenates measured using ELISA, including proinflammatory cytokines IL-1β, IL-18, TNF-α, and IL-6 and healing-associated cytokines IGF-1, TGF-β, IL-10, and VEGF. For all graphs, bars = mean ± SD, n = 6–8. Data compared between groups using ANOVA. *Mean value significantly different from that for mice receiving wild-type bone marrow; P < 0.05.CC BY-NC-ND · PubMed Central
Figure 8 Model of the role of the inflammasome/IL-1β pathway in impaired wound healing in type 2 diabetes. Our data indicate that IL-1β can act as an upstream signal (signal 1) for sustaining inflammasome activity in chronic wound Mp and that ROS are involved in the second signal (signal 2) required for inflammasome activity. Since the inflammasome, in turn, activates IL-1β, this cytokine appears to be part of a proinflammatory positive-feedback loop that promotes a bias toward a proinflammatory Mp phenotype and inhibits upregulation of the prohealing phenotype and healing in diabetic wounds. ab, antibody; ko, knockout.
Figure 8 Model of the role of the inflammasome/IL-1β pathway in impaired wound healing in type 2 diabetes. Our data indicate that IL-1β can act as an upstream signal (signal 1) for sustaining inflammasome activity in chronic wound Mp and that ROS are involved in the second signal (signal 2) required for inflammasome activity. Since the inflammasome, in turn, activates IL-1β, this cytokine appears to be part of a proinflammatory positive-feedback loop that promotes a bias toward a proinflammatory Mp phenotype and inhibits upregulation of the prohealing phenotype and healing in diabetic wounds. ab, antibody; ko, knockout.CC BY-NC-ND · PubMed Central

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  • It may state two separate claims as one. 17
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  • The paper relies on this without support.

    The db/db mouse model of type 2 diabetes is representative of human diabetic wound healing for testing inflammasome-targeted therapies.

    “Diabetic db/db mice, nondiabetic db/+ controls, and C57Bl/6 wild-type controls were obtained from The Jackson Laboratory.”
    “Our findings indicate that sustained inflammasome activity in wound Mp contributes to impaired early healing responses of diabetic wounds and that the inflammasome may represent a new therapeutic target for improving healing in diabetic individuals.”

  • The paper relies on this without support.

    Bone marrow transfer from donor mice to db/db mice specifically targets the inflammasome in macrophages.

    “To more specifically target the inflammasome in Mp, we used bone marrow transfer to determine the role of bone marrow cell–derived inflammasome activity in impaired healing of wounds in diabetic mice.”
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Metadata

Authors
Mirza, R. E., Fang, M. M., Weinheimer-Haus, E. M., Ennis, W. J., & Koh, T. J.
Affiliations
University of Illinois Chicago (US)
Corresponding author
Koh, Timothy J.
ORCID
Venue
Diabetes
Publisher
American Diabetes Association
Published
2014-02-13
Volume
63
Issue
3
Pages
1103-1114
ISSN
  • 0012-1797 (ISSN-L)
  • 1939-327X
DOI
10.2337/db13-0927
PMC
PMC3931398
OpenAlex
W2110231257
Semantic Scholar
4144b2040892a9bd2eef3db0cd10a705cb457147
Cited by
319
References
54
Citations by year
2026: 20 · 2025: 17 · 2024: 48 · 2023: 34 · 2022: 31 · 2021: 34 · 2020: 29 · 2019: 22 · 2018: 20 · 2017: 23 · 2016: 16 · 2015: 13 · 2014: 9
FWCI
13.87
Type
journal article
Language
en
Open access
Licence
Locations
  • Diabetes (publishedVersion, cc-by-nc-nd)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by-nc-nd)
  • PubMed Central (publishedVersion, cc-by-nc-nd)
  • PubMed (publishedVersion)
Funders
  • National Institutes of Health
  • University of Illinois at Urbana-Champaign
  • National Institute of General Medical Sciences (R01GM092850)
  • National Institute of Dental and Craniofacial Research (T32DE018381)
Topics
  • Health Sciences › Medicine › Surgery › Wound Healing and Treatments
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Inflammasome and immune disorders
  • Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Diabetic Foot Ulcer Assessment and Management
Keywords
NLRP3 inflammasome, diabetic wound healing, macrophages, type 2 diabetes, caspase-1, IL-1β, IL-18, reactive oxygen species, db/db mice, inflammasome inhibitors, bone marrow transfer, chronic inflammation
MeSH terms
NLR Family, Pyrin Domain-Containing 3 Protein, Animals, Carrier Proteins, Diabetes Mellitus, Type 2, Female, Humans, Macrophages, Male, Mice, Inbred C57BL, Wound Healing, Reactive Oxygen Species, Caspase 1, Mice, Interleukin-1beta

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