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1.
Nature ; 630(8018): 968-975, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38867043

RESUMO

Obesity is a leading risk factor for progression and metastasis of many cancers1,2, yet can in some cases enhance survival3-5 and responses to immune checkpoint blockade therapies, including anti-PD-1, which targets PD-1 (encoded by PDCD1), an inhibitory receptor expressed on immune cells6-8. Although obesity promotes chronic inflammation, the role of the immune system in the obesity-cancer connection and immunotherapy remains unclear. It has been shown that in addition to T cells, macrophages can express PD-19-12. Here we found that obesity selectively induced PD-1 expression on tumour-associated macrophages (TAMs). Type I inflammatory cytokines and molecules linked to obesity, including interferon-γ, tumour necrosis factor, leptin, insulin and palmitate, induced macrophage PD-1 expression in an mTORC1- and glycolysis-dependent manner. PD-1 then provided negative feedback to TAMs that suppressed glycolysis, phagocytosis and T cell stimulatory potential. Conversely, PD-1 blockade increased the level of macrophage glycolysis, which was essential for PD-1 inhibition to augment TAM expression of CD86 and major histocompatibility complex I and II molecules and ability to activate T cells. Myeloid-specific PD-1 deficiency slowed tumour growth, enhanced TAM glycolysis and antigen-presentation capability, and led to increased CD8+ T cell activity with a reduced level of markers of exhaustion. These findings show that obesity-associated metabolic signalling and inflammatory cues cause TAMs to induce PD-1 expression, which then drives a TAM-specific feedback mechanism that impairs tumour immune surveillance. This may contribute to increased cancer risk yet improved response to PD-1 immunotherapy in obesity.


Assuntos
Neoplasias , Obesidade , Receptor de Morte Celular Programada 1 , Macrófagos Associados a Tumor , Animais , Feminino , Humanos , Masculino , Camundongos , Apresentação de Antígeno/efeitos dos fármacos , Antígeno B7-2/antagonistas & inibidores , Antígeno B7-2/imunologia , Antígeno B7-2/metabolismo , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Linhagem Celular Tumoral , Glicólise/efeitos dos fármacos , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Inibidores de Checkpoint Imunológico/farmacologia , Inibidores de Checkpoint Imunológico/uso terapêutico , Mediadores da Inflamação/imunologia , Mediadores da Inflamação/metabolismo , Ativação Linfocitária , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/antagonistas & inibidores , Camundongos Endogâmicos C57BL , Neoplasias/tratamento farmacológico , Neoplasias/imunologia , Neoplasias/metabolismo , Neoplasias/patologia , Obesidade/imunologia , Obesidade/metabolismo , Fagocitose/efeitos dos fármacos , Receptor de Morte Celular Programada 1/metabolismo , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Macrófagos Associados a Tumor/imunologia , Macrófagos Associados a Tumor/metabolismo , Macrófagos Associados a Tumor/efeitos dos fármacos
3.
J Lipid Res ; 65(10): 100641, 2024 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-39245323

RESUMO

A key organismal response to overnutrition involves the development of new adipocytes through the process of adipogenesis. Preadipocytes sense changes in the systemic nutrient status and metabolites can directly modulate adipogenesis. We previously identified a role of de novo nucleotide biosynthesis in adipogenesis induction, whereby inhibition of nucleotide biosynthesis suppresses the expression of the transcriptional regulators PPARγ and C/EBPα. Here, we set out to identify the global transcriptomic changes associated with the inhibition of nucleotide biosynthesis. Through RNA sequencing (RNAseq), we discovered that mitochondrial signatures were the most altered in response to inhibition of nucleotide biosynthesis. Blocking nucleotide biosynthesis induced rounded mitochondrial morphology, and altered mitochondrial function, and metabolism, reducing levels of tricarboxylic acid cycle intermediates, and increasing fatty acid oxidation (FAO). The loss of mitochondrial function induced by suppression of nucleotide biosynthesis was rescued by exogenous expression of PPARγ. Moreover, inhibition of FAO restored PPARγ expression, mitochondrial protein expression, and adipogenesis in the presence of nucleotide biosynthesis inhibition, suggesting a regulatory role of nutrient oxidation in differentiation. Collectively, our studies shed light on the link between substrate oxidation and transcription in cell fate determination.

4.
Am J Physiol Endocrinol Metab ; 321(3): E376-E391, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34338042

RESUMO

Tissue iron overload is associated with insulin resistance and mitochondrial dysfunction in rodents and humans; however, the mechanisms or cell types that mediate this phenotype are not completely understood. Macrophages (Mɸs) are known to contribute to iron handling; thus, we hypothesized that perturbed iron handling by Mɸs impairs mitochondrial energetics and evokes systemic insulin resistance in mice. Male and female mice with myeloid-targeted (LysMCre) deletion of the canonical iron exporter, ferroportin (Fpn, encoded by Slc40a1), floxed littermates, and C57BL/6J wild-type mice were used to test our hypotheses. Myeloid-targeted deletion of Fpn evoked multitissue iron accumulation and reduced mitochondrial respiration in bone marrow-derived Mɸs, liver leukocytes, and Mɸ-enriched populations from adipose tissue (AT). In addition, a single bolus of exogenous iron administered to C57BL/6J mice phenocopied the loss of Fpn, resulting in a reduction in maximal and mitochondrial reserve capacity in Mɸ-enriched cellular fractions from liver and AT. In vivo exogenous iron chelation restored mitochondrial reserve capacity in liver leukocytes from Fpn LysMCre mice, but had no effect in AT myeloid populations. However, despite the impairments in mitochondrial respiration, neither loss of myeloid-specific Fpn nor exogenous iron overload perturbed glucose homeostasis or systemic insulin action in lean or obese mice, whereas aging coupled with lifelong loss of Fpn unmasked glucose intolerance. Together these data demonstrate that iron handling is critical for the maintenance of macrophage mitochondrial function, but perturbing myeloid iron flux via the loss of Fpn action is not sufficient to evoke systemic insulin resistance in young adult mice. These findings also suggest that if Mɸs are capable of storing iron properly, they have a pronounced ability to withstand iron excess without evoking overt collateral damage and associated insulin resistance that may be age dependent.NEW & NOTEWORTHY We used myeloid-specific knockout of ferroportin to determine whether macrophage iron enrichment alters systemic metabolism. We found that macrophages in several tissues showed mitochondrial defects such as a reduction in mitochondrial reserve capacity. However, insulin action in the mice was preserved. These findings also suggest that Mɸs have a pronounced ability to withstand iron excess without evoking overt collateral damage and associated insulin resistance, which appears to be age dependent.


Assuntos
Proteínas de Transporte de Cátions/metabolismo , Insulina/metabolismo , Macrófagos/metabolismo , Células Mieloides/metabolismo , Animais , Metabolismo Energético , Feminino , Glucose/metabolismo , Glicoproteínas de Membrana , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismo , Receptores de Interleucina-1
5.
J Immunol ; 200(11): 3681-3689, 2018 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-29784764

RESUMO

Treatments for metabolic diseases, such as diet and therapeutics, often provide short-term therapy for metabolic stressors, but relapse is common. Repeated bouts of exposure to, and relief from, metabolic stimuli results in a phenomenon we call "metabolic cycling." Recent human and rodent data suggest metabolic cycling promotes an exaggerated response and ultimately worsened metabolic health. This is particularly evident with cycling of body weight and hypertension. The innate and adaptive immune systems have a profound impact on development of metabolic disease, and current data suggest that immunologic memory may partially explain this association, especially in the context of metabolic cycling. In this Brief Review, we highlight recent work in this field and discuss potential immunologic mechanisms for worsened disease prognosis in individuals who experience metabolic cycling.


Assuntos
Memória Imunológica/imunologia , Doenças Metabólicas/imunologia , Imunidade Adaptativa/imunologia , Animais , Peso Corporal/imunologia , Humanos , Hipertensão/imunologia , Imunidade Inata/imunologia
6.
J Biol Rhythms ; 39(5): 423-439, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39096022

RESUMO

Seasonal daylength, or circadian photoperiod, is a pervasive environmental signal that profoundly influences physiology and behavior. In mammals, the central circadian clock resides in the suprachiasmatic nuclei (SCN) of the hypothalamus where it receives retinal input and synchronizes, or entrains, organismal physiology and behavior to the prevailing light cycle. The process of entrainment induces sustained plasticity in the SCN, but the molecular mechanisms underlying SCN plasticity are incompletely understood. Entrainment to different photoperiods persistently alters the timing, waveform, period, and light resetting properties of the SCN clock and its driven rhythms. To elucidate novel candidate genes for molecular mechanisms of photoperiod plasticity, we performed RNA sequencing on whole SCN dissected from mice raised in long (light:dark [LD] 16:8) and short (LD 8:16) photoperiods. Fewer rhythmic genes were detected in mice subjected to long photoperiod, and in general, the timing of gene expression rhythms was advanced 4-6 h. However, a few genes showed significant delays, including Gem. There were significant changes in the expression of the clock-associated gene Timeless and in SCN genes related to light responses, neuropeptides, gamma aminobutyric acid (GABA), ion channels, and serotonin. Particularly striking were differences in the expression of the neuropeptide signaling genes Prokr2 and Cck, as well as convergent regulation of the expression of 3 SCN light response genes, Dusp4, Rasd1, and Gem. Transcriptional modulation of Dusp4 and Rasd1 and phase regulation of Gem are compelling candidate molecular mechanisms for plasticity in the SCN light response through their modulation of the critical NMDAR-MAPK/ERK-CREB/CRE light signaling pathway in SCN neurons. Modulation of Prokr2 and Cck may critically support SCN neural network reconfiguration during photoperiodic entrainment. Our findings identify the SCN light response and neuropeptide signaling gene sets as rich substrates for elucidating novel mechanisms of photoperiod plasticity. Data are also available at http://circadianphotoperiodseq.com/, where users can view the expression and rhythmic properties of genes across these photoperiod conditions.


Assuntos
Relógios Circadianos , Ritmo Circadiano , Melatonina , Fotoperíodo , Núcleo Supraquiasmático , Transcriptoma , Animais , Masculino , Camundongos , Relógios Circadianos/genética , Núcleo Supraquiasmático/fisiologia , Núcleo Supraquiasmático/metabolismo , Ritmo Circadiano/genética , Melatonina/metabolismo , Camundongos Endogâmicos C57BL
7.
bioRxiv ; 2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38586021

RESUMO

Seasonal daylength, or circadian photoperiod, is a pervasive environmental signal that profoundly influences physiology and behavior. In mammals, the central circadian clock resides in the suprachiasmatic nuclei (SCN) of the hypothalamus where it receives retinal input and synchronizes, or entrains, organismal physiology and behavior to the prevailing light cycle. The process of entrainment induces sustained plasticity in the SCN, but the molecular mechanisms underlying SCN plasticity are incompletely understood. Entrainment to different photoperiods persistently alters the timing, waveform, period, and light resetting properties of the SCN clock and its driven rhythms. To elucidate novel molecular mechanisms of photoperiod plasticity, we performed RNAseq on whole SCN dissected from mice raised in Long (LD 16:8) and Short (LD 8:16) photoperiods. Fewer rhythmic genes were detected in Long photoperiod and in general the timing of gene expression rhythms was advanced 4-6 hours. However, a few genes showed significant delays, including Gem . There were significant changes in the expression clock-associated gene Timeless and in SCN genes related to light responses, neuropeptides, GABA, ion channels, and serotonin. Particularly striking were differences in the expression of the neuropeptide signaling genes Prokr2 and Cck , as well as convergent regulation of the expression of three SCN light response genes, Dusp4 , Rasd1 , and Gem . Transcriptional modulation of Dusp4 and Rasd1, and phase regulation of Gem, are compelling candidate molecular mechanisms for plasticity in the SCN light response through their modulation of the critical NMDAR-MAPK/ERK-CREB/CRE light signaling pathway in SCN neurons. Modulation of Prokr2 and Cck may critically support SCN neural network reconfiguration during photoperiodic entrainment. Our findings identify the SCN light response and neuropeptide signaling gene sets as rich substrates for elucidating novel mechanisms of photoperiod plasticity.

8.
Sci Rep ; 14(1): 4020, 2024 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-38369593

RESUMO

Over-consumption of fructose in adults and children has been linked to increased risk of non-alcoholic fatty liver disease (NAFLD). Recent studies have highlighted the effect of fructose on liver inflammation, fibrosis, and immune cell activation. However, little work summarizes the direct impact of fructose on macrophage infiltration, phenotype, and function within the liver. We demonstrate that chronic fructose diet decreased Kupffer cell populations while increasing transitioning monocytes. In addition, fructose increased fibrotic gene expression of collagen 1 alpha 1 (Col1a1) and tissue metallopeptidase inhibitor 1 (Timp1) as well as inflammatory gene expression of tumor necrosis factor alpha (Tnfa) and expression of transmembrane glycoprotein NMB (Gpnmb) in liver tissue compared to glucose and control diets. Single cell RNA sequencing (scRNAseq) revealed fructose elevated expression of matrix metallopeptidase 12 (Mmp12), interleukin 1 receptor antagonist (Il1rn), and radical S-adenosyl methionine domain (Rsad2) in liver and hepatic macrophages. In vitro studies using IMKC and J774.1 cells demonstrated decreased viability when exposed to fructose. Additionally, fructose increased Gpnmb, Tnfa, Mmp12, Il1rn, and Rsad2 in unpolarized IMKC. By mass spectrometry, C13 fructose tracing detected fructose metabolites in glycolysis and the pentose phosphate pathway (PPP). Inhibition of the PPP further increased fructose induced Il6, Gpnmb, Mmp12, Il1rn, and Rsad2 in nonpolarized IMKC. Taken together, fructose decreases cell viability while upregulating resolution and anti-inflammatory associated genes in Kupffer cells.


Assuntos
Células de Kupffer , Hepatopatia Gordurosa não Alcoólica , Criança , Humanos , Células de Kupffer/metabolismo , Frutose/metabolismo , Via de Pentose Fosfato , Metaloproteinase 12 da Matriz/metabolismo , Fígado/metabolismo , Hepatopatia Gordurosa não Alcoólica/patologia , Fibrose , Fenótipo
9.
bioRxiv ; 2024 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-39345596

RESUMO

Sarcomas are a rare classification of tumor derived from tissues of mesenchymal origin including bone, fat, muscle, cartilage, and blood vessels. These tumors often grow rapidly and have limited treatment options with few significant therapeutic advances in recent years. Liposarcomas (LPSs), the most common type of malignant soft tissue sarcoma, are derived from mesenchymal progenitors that have undergone an adipogenic lineage commitment compared to their multipotent counterparts. Interestingly, the grade of differentiation within LPS can vary highly, and the differentiation status of these tumors can drastically affect prognosis and likelihood of metastasis, making tumor differentiation a potential mechanism to target in liposarcoma development. Here, we show that overexpression of the Hedgehog transcription factor Gli2 in dedifferentiated liposarcoma (DDLPS) cells represses adipogenic differentiation while simultaneously activating markers of osteoblast differentiation in vitro . In addition, we observed marked differences in cytokine expression and secretion, prompting us to perform orthotopic fat pad injections of control and Gli2 overexpressing DDLPS cells. Using flow cytometry, we observed distinct changes in fat pad macrophage populations, with a particular increase in M2-like macrophages. Taken together, we find that overexpression of Gli2 in DDLPS cells alters their differentiation capacity and interactions between tumor cells and macrophages, highlighting a novel role for this developmental transcription factor in liposarcoma pathogenesis.

10.
bioRxiv ; 2024 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-39386686

RESUMO

Obesity is an established risk factor for breast cancer development and worsened prognosis; however, the mechanisms for this association - and the potential benefits of weight loss - have not been fully explored. The adipose environment surrounding breast tumors, which is inflamed in obesity, has been implicated in tumor progression. An emerging therapeutic target for cancer is TREM2, a transmembrane receptor of the immunoglobulin superfamily that is expressed on macrophages in adipose tissue and tumors. We utilized genetic loss of function (Trem2 +,+ and Trem2 -/-) models and dietary (lean, obese, and weight loss) intervention approaches to examine impacts on postmenopausal breast cancer. Remarkably, Trem2 deficiency ameliorated tumor growth in lean, but not obese or weight loss mice. Single-cell RNA sequencing, in conjunction with VDJ sequencing of tumor and tumor-adjacent mammary adipose tissue (mATTum-adj) immune cells, revealed that tumors of lean Trem2 -/- mice exhibited a shift in clonal CD8+ T cells from an exhausted to an effector memory state, accompanied with increased clonality of CD4+ Th1 cells, that was not observed in any other diet-genotype group. Notably, identical T cell clonotypes were identified in the tumor and mATTum-adj of the same mouse. Finally, an immune checkpoint study demonstrated that αPD-1 therapy restricted tumor growth in lean and weight loss, but not obese mice. We conclude that weight history is relevant when considering potential efficacy of TREM2 inhibition in postmenopausal breast cancer. This work reveals immunological interactions between tumors and surrounding adipose tissue, highlighting significant differences under obese and weight loss conditions.

11.
bioRxiv ; 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-38014269

RESUMO

Our recent study showed weight cycled mice have increased adipose mast cells compared to obese mice by single cell RNA-sequencing. Here, we aimed to confirm and elucidate these changes. Further analysis of our dataset showed that our initial mast cell cluster could subcluster into two unique populations: one with very high expression of classical mast cell markers and another with elevated lipid handling and antigen presentation genes. This new mast cell cluster accounted for most of the mast cells in the weight cycled group although it was not possible to detect the different populations by new studies with flow cytometry or Toluidine blue staining in mice, possibly due to a downregulation in classical mast cell genes. Interestingly, a pilot study in humans did suggest the existence of two mast cell populations in subcutaneous adipose tissue from obese women that appear similar to the murine populations detected by sequencing; one of which was significantly correlated with weight variance. Together, these data suggest that weight cycling may induce a unique population of mast cells similar to lipid associated macrophages. Future studies will focus on isolation of these cells to better determine their lineage, differentiation, and functional roles.

12.
Cardiovasc Res ; 119(13): 2312-2328, 2023 10 24.
Artigo em Inglês | MEDLINE | ID: mdl-37314125

RESUMO

AIMS: Heart failure with preserved ejection fraction (HFpEF) is characterized by diastolic dysfunction, microvascular dysfunction, and myocardial fibrosis with recent evidence implicating the immune system in orchestrating cardiac remodelling. METHODS AND RESULTS: Here, we show the mouse model of deoxycorticosterone acetate (DOCA)-salt hypertension induces key elements of HFpEF, including diastolic dysfunction, exercise intolerance, and pulmonary congestion in the setting of preserved ejection fraction. A modified single-cell sequencing approach, cellular indexing of transcriptomes and epitopes by sequencing, of cardiac immune cells reveals an altered abundance and transcriptional signature in multiple cell types, most notably cardiac macrophages. The DOCA-salt model results in differential expression of several known and novel genes in cardiac macrophages, including up-regulation of Trem2, which has been recently implicated in obesity and atherosclerosis. The role of Trem2 in hypertensive heart failure, however, is unknown. We found that mice with genetic deletion of Trem2 exhibit increased cardiac hypertrophy, diastolic dysfunction, renal injury, and decreased cardiac capillary density after DOCA-salt treatment compared to wild-type controls. Moreover, Trem2-deficient macrophages have impaired expression of pro-angiogenic gene programmes and increased expression of pro-inflammatory cytokines. Furthermore, we found that plasma levels of soluble TREM2 are elevated in DOCA-salt treated mice and humans with heart failure. CONCLUSIONS: Together, our data provide an atlas of immunological alterations that can lead to improved diagnostic and therapeutic strategies for HFpEF. We provide our dataset in an easy to explore and freely accessible web application making it a useful resource for the community. Finally, our results suggest a novel cardioprotective role for Trem2 in hypertensive heart failure.


Assuntos
Cardiomiopatias , Acetato de Desoxicorticosterona , Insuficiência Cardíaca , Hipertensão , Humanos , Camundongos , Animais , Volume Sistólico/fisiologia , Hipertensão/induzido quimicamente , Hipertensão/genética , Hipertensão/metabolismo , Células Mieloides/metabolismo , Leucócitos/metabolismo , Glicoproteínas de Membrana/genética , Receptores Imunológicos/genética
13.
Front Immunol ; 13: 984859, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36713396

RESUMO

Introduction: Weight loss improves obesity-associated diabetes risk. However, most individuals regain weight, which worsens the risk of developing diabetes and cardiovascular disease. We previously reported that male mice retain obesity-associated immunological changes even after weight loss, suggesting that immune cells may remember the state of obesity. Therefore, we hypothesized that cycles of weight gain and loss, otherwise known as weight cycling, can induce innate memory in adipose macrophages. Methods: Bone marrow derived macrophages were primed with palmitic acid or adipose tissue conditioned media in a culture model of innate immune memory. Mice also put on low fat or high fat diets over 14-27 weeks to induce weight gain, weight loss, and weight cycling. Results: Priming cells with palmitic acid or adipose tissue conditioned media from obese mice increased maximal glycolysis and oxidative phosphorylation and increased LPS-induced TNFα and IL-6 production. Palmitic acid effects were dependent on TLR4 and impaired by methyltransferase inhibition and AMPK activation. While weight loss improved glucose tolerance in mice, adipose macrophages were primed for greater activation to subsequent stimulation by LPS ex vivo as measured by cytokine production. In the model of weight cycling, adipose macrophages had elevated metabolism and secreted higher levels of basal TNFα, suggesting that weight loss can also prime macrophages for heighted activation to weight regain. Discussion: Together, these data suggest that weight loss following obesity can prime adipose macrophages for enhanced inflammation upon weight regain. This innate immune memory response may contribute to worsened glucose tolerance following weight cycling.


Assuntos
Diabetes Mellitus , Resistência à Insulina , Masculino , Camundongos , Animais , Fator de Necrose Tumoral alfa/metabolismo , Ciclo de Peso , Imunidade Treinada , Ácido Palmítico/farmacologia , Ácido Palmítico/metabolismo , Meios de Cultivo Condicionados/metabolismo , Lipopolissacarídeos/metabolismo , Resistência à Insulina/fisiologia , Tecido Adiposo , Obesidade , Macrófagos , Aumento de Peso , Diabetes Mellitus/metabolismo , Redução de Peso , Glucose/metabolismo
14.
Nat Commun ; 13(1): 2950, 2022 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-35618862

RESUMO

Within adipose tissue (AT), immune cells and parenchymal cells closely interact creating a complex microenvironment. In obesity, immune cell derived inflammation contributes to insulin resistance and glucose intolerance. Diet-induced weight loss improves glucose tolerance; however, weight regain further exacerbates the impairment in glucose homeostasis observed with obesity. To interrogate the immunometabolic adaptations that occur in AT during murine weight loss and weight regain, we utilized cellular indexing of transcriptomes and epitopes by sequencing (CITEseq) in male mice. Obesity-induced imprinting of AT immune cells persisted through weight-loss and progressively worsened with weight regain, ultimately leading to impaired recovery of type 2 regulatory cells, activation of antigen presenting cells, T cell exhaustion, and enhanced lipid handling in macrophages in weight cycled mice. This work provides critical groundwork for understanding the immunological causes of weight cycling-accelerated metabolic disease. For further discovery, we provide an open-access web portal of diet-induced AT immune cell imprinting: https://hastylab.shinyapps.io/MAIseq .


Assuntos
Tecido Adiposo , Redução de Peso , Tecido Adiposo/metabolismo , Animais , Glucose/metabolismo , Masculino , Camundongos , Obesidade/metabolismo , Fenótipo , Aumento de Peso
15.
Diabetes ; 71(11): 2313-2330, 2022 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-35802127

RESUMO

In the setting of obesity and insulin resistance, glycemia is controlled in part by ß-cell compensation and subsequent hyperinsulinemia. Weight loss improves glycemia and decreases hyperinsulinemia, whereas weight cycling worsens glycemic control. The mechanisms responsible for weight cycling-induced deterioration in glucose homeostasis are poorly understood. Thus, we aimed to pinpoint the main regulatory junctions at which weight cycling alters glucose homeostasis in mice. Using in vivo and ex vivo procedures we show that despite having worsened glucose tolerance, weight-cycled mice do not manifest impaired whole-body insulin action. Instead, weight cycling reduces insulin secretory capacity in vivo during clamped hyperglycemia and ex vivo in perifused islets. Islets from weight-cycled mice have reduced expression of factors essential for ß-cell function (Mafa, Pdx1, Nkx6.1, Ucn3) and lower islet insulin content, compared with those from obese mice, suggesting inadequate transcriptional and posttranscriptional response to repeated nutrient overload. Collectively, these data support a model in which pancreatic plasticity is challenged in the face of large fluctuations in body weight resulting in a mismatch between glycemia and insulin secretion in mice.


Assuntos
Hiperinsulinismo , Resistência à Insulina , Ilhotas Pancreáticas , Camundongos , Animais , Insulina/metabolismo , Secreção de Insulina , Ciclo de Peso , Obesidade/metabolismo , Resistência à Insulina/fisiologia , Glicemia/metabolismo , Dieta , Hiperinsulinismo/metabolismo , Insulina Regular Humana , Ilhotas Pancreáticas/metabolismo , Glucose/metabolismo
16.
Sci Transl Med ; 14(641): eabm6586, 2022 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-35442705

RESUMO

Porous, resorbable biomaterials can serve as temporary scaffolds that support cell infiltration, tissue formation, and remodeling of nonhealing skin wounds. Synthetic biomaterials are less expensive to manufacture than biologic dressings and can achieve a broader range of physiochemical properties, but opportunities remain to tailor these materials for ideal host immune and regenerative responses. Polyesters are a well-established class of synthetic biomaterials; however, acidic degradation products released by their hydrolysis can cause poorly controlled autocatalytic degradation. Here, we systemically explored reactive oxygen species (ROS)-degradable polythioketal (PTK) urethane (UR) foams with varied hydrophilicity for skin wound healing. The most hydrophilic PTK-UR variant, with seven ethylene glycol (EG7) repeats flanking each side of a thioketal bond, exhibited the highest ROS reactivity and promoted optimal tissue infiltration, extracellular matrix (ECM) deposition, and reepithelialization in porcine skin wounds. EG7 induced lower foreign body response, greater recruitment of regenerative immune cell populations, and resolution of type 1 inflammation compared to more hydrophobic PTK-UR scaffolds. Porcine wounds treated with EG7 PTK-UR foams had greater ECM production, vascularization, and resolution of proinflammatory immune cells compared to polyester UR foam-based NovoSorb Biodegradable Temporizing Matrix (BTM)-treated wounds and greater early vascular perfusion and similar wound resurfacing relative to clinical gold standard Integra Bilayer Wound Matrix (BWM). In a porcine ischemic flap excisional wound model, EG7 PTK-UR treatment led to higher wound healing scores driven by lower inflammation and higher reepithelialization compared to NovoSorb BTM. PTK-UR foams warrant further investigation as synthetic biomaterials for wound healing applications.


Assuntos
Materiais Biocompatíveis , Cicatrização , Animais , Bandagens , Materiais Biocompatíveis/farmacologia , Inflamação , Poliésteres , Espécies Reativas de Oxigênio , Pele , Suínos
17.
Obesity (Silver Spring) ; 29(5): 790-801, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33899336

RESUMO

Chronic inflammation is considered a precipitating factor and possibly an underlying cause of many noncommunicable diseases, including cardiovascular disease, metabolic diseases, and some cancers. Obesity, which manifests in more than 650 million people worldwide, is the most common chronic inflammatory condition, with visceral adiposity thought to be the major inflammatory hub that links obesity and chronic disease. Adipose tissue (AT) inflammation is triggered or heightened in large part by (1) accelerated immune cell recruitment, (2) reshaping of the AT stromal-immuno landscape (e.g., immune cells, endothelial cells, fibroblasts, adipocyte progenitors), and (3) perturbed AT immune cell function. Exercise, along with diet management, is a cornerstone in promoting weight loss and preventing weight regain. This review focuses on evidence that increased physical activity reduces AT inflammation caused by hypercaloric diets or genetic obesity. The precise cell types and mechanisms responsible for the therapeutic effects of exercise on AT inflammation remain poorly understood. This review summarizes what is known about obesity-induced AT inflammation and immunomodulation and highlights mechanisms by which aerobic exercise combats inflammation by remodeling the AT immune landscape. Furthermore, key areas are highlighted that require future exploration and novel discoveries into the burgeoning field of how the biology of exercise affects AT immunity.


Assuntos
Tecido Adiposo/imunologia , Exercício Físico/fisiologia , Inflamação/imunologia , Obesidade/imunologia , Humanos
18.
Biomaterials ; 268: 120528, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33285438

RESUMO

This work establishes that Kupffer cell release of platelet activating factor (PAF), a lipidic molecule with pro-inflammatory and vasoactive signaling properties, dictates dose-limiting siRNA nanocarrier-associated toxicities. High-dose intravenous injection of siRNA-polymer nano-polyplexes (si-NPs) elicited acute, shock-like symptoms in mice, associated with increased plasma PAF and consequently reduced PAF acetylhydrolase (PAF-AH) activity. These symptoms were completely prevented by prophylactic PAF receptor inhibition or Kupffer cell depletion. Assessment of varied si-NP chemistries confirmed that toxicity level correlated to relative uptake of the carrier by liver Kupffer cells and that this toxicity mechanism is dependent on carrier endosome disruptive function. 4T1 tumor-bearing mice, which exhibit increased circulating leukocytes, displayed greater sensitivity to these toxicities. PAF-mediated toxicities were generalizable to commercial delivery reagent in vivo-jetPEI® and an MC3 lipid formulation matched to an FDA-approved nanomedicine. These collective results establish Kupffer cell release of PAF as a key mediator of siRNA nanocarrier toxicity and identify PAFR inhibition as an effective strategy to increase siRNA nanocarrier tolerated dose.


Assuntos
Células de Kupffer , Fator de Ativação de Plaquetas , Animais , Transporte Biológico , Células de Kupffer/metabolismo , Camundongos , Fator de Ativação de Plaquetas/metabolismo , RNA Mensageiro/metabolismo , Transdução de Sinais
19.
Trends Pharmacol Sci ; 39(6): 536-546, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29628274

RESUMO

Macrophages are cells of the innate immune system that are resident in all tissues, including metabolic organs such as the liver and adipose tissue (AT). Because of their phenotypic flexibility, they play beneficial roles in tissue homeostasis, but they also contribute to the progression of metabolic disease. Thus, they are ideal therapeutic targets for diseases such as insulin resistance (IR), nonalcoholic fatty liver disease (NAFLD), and atherosclerosis. Recently, discoveries in the area of drug delivery have facilitated phenotype-specific targeting of macrophages. In this review we discuss advances in potential therapeutics for metabolic diseases via macrophage-specific delivery. We highlight micro- and nanoparticles, liposomes, and oligopeptide complexes, and how they can be used to alter macrophage phenotype for a more metabolically favorable tissue environment.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Expressão Gênica/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Doenças Metabólicas/tratamento farmacológico , Preparações Farmacêuticas/administração & dosagem , Humanos , Macrófagos/imunologia , Doenças Metabólicas/imunologia , Terapia de Alvo Molecular
20.
Diabetes ; 67(11): 2361-2376, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30181158

RESUMO

Adipose tissue (AT) CD4+ and CD8+ T cells contribute to obesity-associated insulin resistance. Prior studies identified conserved T-cell receptor (TCR) chain families in obese AT, but the presence and clonal expansion of specific TCR sequences in obesity has not been assessed. We characterized AT and liver CD8+ and CD4+ TCR repertoires of mice fed a low-fat diet (LFD) and high-fat diet (HFD) using deep sequencing of the TCRß chain to quantify clonal expansion, gene usage, and CDR3 sequence. In AT CD8+ T cells, HFD reduced TCR diversity, increased the prevalence of public TCR clonotypes, and selected for TCR CDR3 regions enriched in positively charged and less polarized amino acids. Although TCR repertoire alone could distinguish between LFD- and HFD-fed mice, these properties of the CDR3 region of AT CD8+ T cells from HFD-fed mice led us to examine the role of negatively charged and nonpolar isolevuglandin (isoLG) adduct-containing antigen-presenting cells within AT. IsoLG-adducted protein species were significantly higher in AT macrophages of HFD-fed mice; isoLGs were elevated in M2-polarized macrophages, promoting CD8+ T-cell activation. Our findings demonstrate that clonal TCR expansion that favors positively charged CDR3s accompanies HFD-induced obesity, which may be an antigen-driven response to isoLG accumulation in macrophages.


Assuntos
Tecido Adiposo/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Regiões Determinantes de Complementaridade/metabolismo , Fígado/metabolismo , Obesidade/metabolismo , Prostaglandinas/metabolismo , Tecido Adiposo/imunologia , Animais , Linfócitos T CD8-Positivos/imunologia , Dieta Hiperlipídica , Teste de Tolerância a Glucose , Resistência à Insulina , Fígado/imunologia , Masculino , Camundongos , Obesidade/imunologia
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