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1.
BMC Med ; 22(1): 106, 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38454391

RESUMO

BACKGROUND: Breastfeeding (BF) confers metabolic benefits to infants, including reducing risks of metabolic syndrome such as obesity and diabetes later in life. However, the underlying mechanism is not yet fully understood. Hence, we aim to investigate the impacts of BF on the metabolic organs of infants. METHODS: Previous literatures directly studying the influences of BF on offspring's metabolic organs in both animal models and humans were comprehensively reviewed. A microarray dataset of intestinal gene expression comparing infants fed on breastmilk versus formula milk was analyzed. RESULTS: Reanalysis of microarray data showed that BF is associated with enhanced intestinal gluconeogenesis in infants. This resembles observations in other mammalian species showing that BF was also linked to increased gluconeogenesis. CONCLUSIONS: BF is associated with enhanced intestinal gluconeogenesis in infants, which may underpin its metabolic advantages through finetuning metabolic homeostasis. This observation seems to be conserved across species, hinting its biological significance.


Assuntos
Aleitamento Materno , Síndrome Metabólica , Lactente , Feminino , Animais , Humanos , Gluconeogênese , Mamíferos
3.
Eur J Immunol ; 53(11): e2350521, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37595951

RESUMO

Regulatory T cells (Treg) maintain immune homeostasis due to their anti-inflammatory functions. They can be generated either centrally in the thymus or in peripheral organs. Metabolites such as short-chain fatty acids produced by intestinal microbiota can induce peripheral Treg differentiation, by activating G-protein-coupled-receptors like GPR109A. In this study, we identified a novel role for GPR109A in thymic Treg development. We found that Gpr109a-/- mice had increased Treg under basal conditions in multiple organs compared with WT mice. GPR109A was not expressed on T cells but on medullary thymic epithelial cells (mTECs), as revealed by single-cell RNA sequencing in both mice and humans and confirmed by flow cytometry in mice. mTECs isolated from Gpr109a-/- mice had higher expression of autoimmune regulator (AIRE), the key regulator of Treg development, while the subset of mTECs that did not express Gpr109a in the WT displayed increased Aire expression and also enhanced signaling related to mTEC functionality. Increased thymic Treg in Gpr109a-/- mice was associated with protection from experimental autoimmune encephalomyelitis, with ameliorated clinical signs and reduced inflammation. This work identifies a novel role for GPR109A and possibly the gut microbiota, on thymic Treg development via its regulation of mTECs.


Assuntos
Células Epiteliais , Linfócitos T Reguladores , Animais , Humanos , Camundongos , Diferenciação Celular , Citometria de Fluxo , Camundongos Endogâmicos C57BL , Transdução de Sinais , Timo
4.
Nat Commun ; 14(1): 4409, 2023 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-37479702

RESUMO

The metabolic effects of sugars and fat lie at the heart of the "carbohydrate vs fat" debate on the global obesity epidemic. Here, we use nutritional geometry to systematically investigate the interaction between dietary fat and the major monosaccharides, fructose and glucose, and their impact on body composition and metabolic health. Male mice (n = 245) are maintained on one of 18 isocaloric diets for 18-19 weeks and their metabolic status is assessed through in vivo procedures and by in vitro assays involving harvested tissue samples. We find that in the setting of low and medium dietary fat content, a 50:50 mixture of fructose and glucose (similar to high-fructose corn syrup) is more obesogenic and metabolically adverse than when either monosaccharide is consumed alone. With increasing dietary fat content, the effects of dietary sugar composition on metabolic status become less pronounced. Moreover, higher fat intake is more harmful for glucose tolerance and insulin sensitivity irrespective of the sugar mix consumed. The type of fat consumed (soy oil vs lard) does not modify these outcomes. Our work shows that both dietary fat and sugars can lead to adverse metabolic outcomes, depending on the dietary context. This study shows how the principles of the two seemingly conflicting models of obesity (the "energy balance model" and the "carbohydrate insulin model") can be valid, and it will help in progressing towards a unified model of obesity. The main limitations of this study include the use of male mice of a single strain, and not testing the metabolic effects of fructose intake via sugary drinks, which are strongly linked to human obesity.


Assuntos
Sacarose na Dieta , Açúcares , Humanos , Masculino , Camundongos , Animais , Sacarose na Dieta/efeitos adversos , Gorduras na Dieta/efeitos adversos , Dieta/efeitos adversos , Obesidade/metabolismo , Glucose/farmacologia , Frutose/efeitos adversos
5.
Eur J Immunol ; 53(7): e2250163, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37137164

RESUMO

The gut microbiota has co-evolved with its host, and commensal bacteria can influence both the host's immune development and function. Recently, a role has emerged for bacterial extracellular vesicles (BEVs) as potent immune modulators. BEVs are nanosized membrane vesicles produced by all bacteria, possessing the membrane characteristics of the originating bacterium and carrying an internal cargo that may include nucleic acid, proteins, lipids, and metabolites. Thus, BEVs possess multiple avenues for regulating immune processes, and have been implicated in allergic, autoimmune, and metabolic diseases. BEVs are biodistributed locally in the gut, and also systemically, and thus have the potential to affect both the local and systemic immune responses. The production of gut microbiota-derived BEVs is regulated by host factors such as diet and antibiotic usage. Specifically, all aspects of nutrition, including macronutrients (protein, carbohydrates, and fat), micronutrients (vitamins and minerals), and food additives (the antimicrobial sodium benzoate), can regulate BEV production. This review summarizes current knowledge of the powerful links between nutrition, antibiotics, gut microbiota-derived BEV, and their effects on immunity and disease development. It highlights the potential of targeting or utilizing gut microbiota-derived BEV as a therapeutic intervention.


Assuntos
Vesículas Extracelulares , Microbioma Gastrointestinal , Microbiota , Dieta , Microbioma Gastrointestinal/fisiologia , Bactérias , Antibacterianos , Vesículas Extracelulares/metabolismo
6.
Acta Neuropathol Commun ; 11(1): 60, 2023 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-37016414

RESUMO

As the resident parenchymal myeloid population in the central nervous system (CNS), microglia are strategically positioned to respond to neurotropic virus invasion and have been implicated in promoting both disease resolution and progression in the acute and post-infectious phase of virus encephalitis. In a mouse model of West Nile virus encephalitis (WNE), infection of the CNS results in recruitment of large numbers of peripheral immune cells into the brain, the majority being nitric oxide (NO)-producing Ly6Chi inflammatory monocyte-derived cells (MCs). In this model, these cells enhance immunopathology and mortality. However, the contribution of microglia to this response is currently undefined. Here we used a combination of experimental tools, including single-cell RNA sequencing (scRNA-seq), microglia and MC depletion reagents, high-dimensional spectral cytometry and computational algorithms to dissect the differential contribution of microglia and MCs to the anti-viral immune response in severe neuroinflammation seen in WNE. Intriguingly, analysis of scRNA-seq data revealed 6 unique microglia and 3 unique MC clusters that were predominantly timepoint-specific, demonstrating substantial transcriptional adaptation with disease progression over the course of WNE. While microglia and MC adopted unique gene expression profiles, gene ontology enrichment analysis, coupled with microglia and MC depletion studies, demonstrated a role for both of these cells in the trafficking of peripheral immune cells into the CNS, T cell responses and viral clearance. Over the course of infection, microglia transitioned from a homeostatic to an anti-viral and then into an immune cell-recruiting phenotype. Conversely, MC adopted antigen-presenting, immune cell-recruiting and NO-producing phenotypes, which all had anti-viral function. Overall, this study defines for the first time the single-cell transcriptomic responses of microglia and MCs over the course of WNE, demonstrating both protective and pathological roles of these cells that could potentially be targeted for differential therapeutic intervention to dampen immune-mediated pathology, while maintaining viral clearance functions.


Assuntos
Microglia , Febre do Nilo Ocidental , Animais , Camundongos , Microglia/patologia , Monócitos , Transcriptoma , Febre do Nilo Ocidental/patologia , Encéfalo/patologia
7.
Nucleic Acids Res ; 51(W1): W33-W38, 2023 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-37070199

RESUMO

Increasing data in allostery are requiring analysis of coupling relationships among different allosteric sites on a single protein. Here, based on our previous efforts on reversed allosteric communication theory, we have developed AlloReverse, a web server for multiscale analysis of multiple allosteric regulations. AlloReverse integrates protein dynamics and machine learning to discover allosteric residues, allosteric sites and regulation pathways. Especially, AlloReverse could reveal hierarchical relationships between different pathways and couplings among allosteric sites, offering a whole map of allostery. The web server shows a good performance in re-emerging known allostery. Moreover, we applied AlloReverse to explore global allostery on CDC42 and SIRT3. AlloReverse predicted novel allosteric sites and allosteric residues in both systems, and the functionality of sites was validated experimentally. It also suggests a possible scheme for combined therapy or bivalent drugs on SIRT3. Taken together, AlloReverse is a novel workflow providing a complete regulation map and is believed to aid target identification, drug design and understanding of biological mechanisms. AlloReverse is freely available to all users at https://mdl.shsmu.edu.cn/AlloReverse/ or http://www.allostery.net/AlloReverse/.


Assuntos
Sirtuína 3 , Regulação Alostérica , Descoberta de Drogas , Sítio Alostérico , Proteínas/química
8.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-973237

RESUMO

ObjectiveTo construct 131Ⅰ-labeled hepatoma nucleic acid nanotrain and to explore its feasibility as a new nuclide carrier targeting hepatoma. MethodsThree short nucleic acid chains self-assembled to a long nucleic acid chain after being annealed, and 131Ⅰ-NT was obtained by radioiodine labeling using chloramine T method. The labeling efficiency and radiochemical purity of the nanoparticles were measured by paper chromatography. The stability of the labeled products in vitro at different temperatures and different storage solvents was detected. The specific uptake of nanoparticles by hepatocellular carcinoma cells was observed by laser confocal microscopy, and the radioactive uptake ratio of 131Ⅰ-NT combined with human hepatocellular carcinoma cell HepG2 and normal hepatocyte L02 was measured. The biodistribution of 131Ⅰ-NT was obtained through injecting 131Ⅰ-NT into HepG2 tumor-bearing mice via tail vein. ResultsThe labeling rate of 131Ⅰ-NT was (93.05±0.74) %, and the radiochemical purity post purification was (98.35±0.32) %. Its radiochemical purity in PBS and pure serum at 4℃ for 24 h was (92.77±0.04) % and (89.43±0.2) %, respectively. The radioactivity uptake rate of HepG2 cells was higher than that of L02 cells after 131Ⅰ-NT was incubated with two kinds of cells for 2 h significantly. After injection of 131Ⅰ-NT through tail vein, the radioactive uptake per gram of tumor tissue were (4.9±0.55)%ID/g, (10.12±0.32)%ID/g and (4.25±0.31)%ID/g at 30 min, 1 h and 2 h, respectively. The T/M ratio was 7.33±2.04, 36.54±12.72 and 44.93±7.90 respectively. ConclusionsThe 131Ⅰ-labeled long chain nucleic acid nanotrain was constructed successfully, which possesses relatively high stability in vitro , and high targeting ability to HepG2 cells in vitro and HepG2 tumor-bearing mouse model. Our study demonstrated that 131Ⅰ-NT may be a potential radionuclide carrier targeting human liver cancer, which provides a new idea for the targeted radionuclide diagnosis and treatment of hepatocellular carcinoma.

9.
Cell Rep ; 40(7): 111191, 2022 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-35977500

RESUMO

Psoriasis has long been associated with inflammatory bowel disease (IBD); however, a causal link is yet to be established. Here, we demonstrate that imiquimod-induced psoriasis (IMQ-pso) in mice disrupts gut homeostasis, characterized by increased proportions of colonic CX3CR1hi macrophages, altered cytokine production, and bacterial dysbiosis. Gut microbiota from these mice produce higher levels of succinate, which induce de novo proliferation of CX3CR1hi macrophages ex vivo, while disrupted gut homeostasis primes IMQ-pso mice for more severe colitis with dextran sulfate sodium (DSS) challenge. These results demonstrate that changes in the gut environment in psoriasis lead to greater susceptibility to IBD in mice, suggesting a two-hit requirement, that is, psoriasis-induced altered gut homeostasis and a secondary environmental challenge. This may explain the increased prevalence of IBD in patients with psoriasis.


Assuntos
Colite , Doenças Inflamatórias Intestinais , Psoríase , Animais , Colo/microbiologia , Sulfato de Dextrana , Modelos Animais de Doenças , Disbiose/complicações , Imiquimode/efeitos adversos , Doenças Inflamatórias Intestinais/etiologia , Camundongos , Camundongos Endogâmicos C57BL , Psoríase/induzido quimicamente
10.
J Chem Inf Model ; 62(17): 4222-4231, 2022 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-35994329

RESUMO

K-Ras4B, the most frequently mutated Ras isoform in human tumors, plays a vital part in cell growth, differentiation, and survival. Its tail, the C-terminal hypervariable region (HVR), is involved in anchoring K-Ras4B at the cellular plasma membrane and in isoform-specific protein-protein interactions and signaling. In the inactive guanosine diphosphate-bound state, the intrinsically disordered HVR interacts with the catalytic domain at the effector-binding region, rendering K-Ras4B in its autoinhibited state. Activation releases the HVR from the catalytic domain, with its ensemble favoring an ordered α-helical structure. The large-scale conformational transition of the HVR from the intrinsically disordered to the ordered conformation remains poorly understood. Here, we deploy a computational scheme that integrates a transition path-generation algorithm, extensive molecular dynamics simulation, and Markov state model analysis to investigate the conformational landscape of the HVR transition pathway. Our findings reveal a stepwise pathway for the HVR transition and uncover several key conformational substates along the transition pathway. Importantly, key interactions between the HVR and the catalytic domain are unraveled, highlighting the pathogenesis of K-Ras4B mild mutations in several congenital developmental anomaly syndromes. Together, these findings provide a deeper understanding of the HVR transition mechanism and the regulation of K-Ras4B activity at an atomic level.


Assuntos
Simulação de Dinâmica Molecular , Proteínas Proto-Oncogênicas p21(ras) , Domínio Catalítico , Membrana Celular/metabolismo , Guanosina Difosfato/química , Guanosina Difosfato/metabolismo , Humanos , Isoformas de Proteínas/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética
11.
Nat Commun ; 13(1): 4336, 2022 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-35896537

RESUMO

Secretory IgA is a key mucosal component ensuring host-microbiota mutualism. Here we use nutritional geometry modelling in mice fed 10 different macronutrient-defined, isocaloric diets, and identify dietary protein as the major driver of secretory IgA production. Protein-driven secretory IgA induction is not mediated by T-cell-dependent pathways or changes in gut microbiota composition. Instead, the microbiota of high protein fed mice produces significantly higher quantities of extracellular vesicles, compared to those of mice fed high-carbohydrate or high-fat diets. These extracellular vesicles activate Toll-like receptor 4 to increase the epithelial expression of IgA-inducing cytokine, APRIL, B cell chemokine, CCL28, and the IgA transporter, PIGR. We show that succinate, produced in high concentrations by microbiota of high protein fed animals, increases generation of reactive oxygen species by bacteria, which in turn promotes extracellular vesicles production. Here we establish a link between dietary macronutrient composition, gut microbial extracellular vesicles release and host secretory IgA response.


Assuntos
Vesículas Extracelulares , Microbioma Gastrointestinal , Animais , Proteínas na Dieta , Vesículas Extracelulares/metabolismo , Imunoglobulina A Secretora/metabolismo , Camundongos , Linfócitos T/metabolismo
12.
Front Mol Biosci ; 9: 933676, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35874618

RESUMO

Glucocorticoid receptor (GR) regulates various cellular functions. Given its broad influence on metabolic activities, it has been the target of drug discovery for decades. However, how drugs induce conformational changes in GR has remained elusive. Herein, we used five GR agonists (dex, AZ938, pred, cor, and dibC) with different efficacies to investigate which aspect of the ligand induced the differences in efficacy. We performed molecular dynamics simulations on the five systems (dex-, AZ938-, pred-, cor-, and dibC-bound systems) and observed a distinct discrepancy in the conformation of the cofactor TIF2. Moreover, we discovered ligand-induced differences regarding the level of conformational changes posed by the binding of cofactor TIF2 and identified a pair of essential residues D590 and T39. We further found a positive correlation between the efficacies of ligands and the interaction of the two binding pockets' domains, where D590 and T739 were involved, implying their significance in the participation of allosteric communication. Using community network analysis, two essential communities containing D590 and T739 were identified with their connectivity correlating to the efficacy of ligands. The potential communication pathways between these two residues were revealed. These results revealed the underlying mechanism of allosteric communication between the ligand-binding and cofactor-binding pockets and identified a pair of important residues in the allosteric communication pathway, which can serve as a guide for future drug discovery.

13.
Front Nutr ; 9: 878382, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35529463

RESUMO

Modern industrial practices have transformed the human diet over the last century, increasing the consumption of processed foods. Dietary imbalance of macro- and micro-nutrients and excessive caloric intake represent significant risk factors for various inflammatory disorders. Increased ingestion of food additives, residual contaminants from agricultural practices, food processing, and packaging can also contribute deleteriously to disease development. One common hallmark of inflammatory disorders, such as autoimmunity and allergies, is the defect in anti-inflammatory regulatory T cell (Treg) development and/or function. Treg represent a highly heterogeneous population of immunosuppressive immune cells contributing to peripheral tolerance. Tregs either develop in the thymus from autoreactive thymocytes, or in the periphery, from naïve CD4+ T cells, in response to environmental antigens and cues. Accumulating evidence demonstrates that various dietary factors can directly regulate Treg development. These dietary factors can also indirectly modulate Treg differentiation by altering the gut microbiota composition and thus the production of bacterial metabolites. This review provides an overview of Treg ontogeny, both thymic and peripherally differentiated, and highlights how diet and gut microbiota can regulate Treg development and function.

14.
Front Mol Biosci ; 9: 860962, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35463958

RESUMO

The Ras-specific guanine nucleotide exchange factors Son of Sevenless (SOS) regulates Ras activation by converting inactive GDP-bound to active GTP-bound states. The catalytic activity of Ras is further allosterically regulated by GTP-Ras bound to a distal site through a positive feedback loop. To address the mechanism underlying the long-range allosteric activation of the catalytic K-Ras4B by an additional allosteric GTP-Ras through SOS, we employed molecular dynamics simulation of the K-Ras4BG13D•SOScat complex with and without an allosteric GTP-bound K-Ras4BG13D. We found that the binding of an allosteric GTP-K-Ras4BG13D enhanced the affinity between the catalytic K-Ras4BG13D and SOScat, forming a more stable conformational state. The peeling away of the switch I from the nucleotide binding site facilitated the dissociation of GDP, thereby contributing to the increased nucleotide exchange rate. The community networks further showed stronger edge connection upon allosteric GTP-K-Ras4BG13D binding, which represented an increased interaction between catalytic K-Ras4BG13D and SOScat. Moreover, GTP-K-Ras4BG13D binding transmitted allosteric signaling pathways though the Cdc25 domain of SOS that enhanced the allosteric regulatory from the K-Ras4BG13D allosteric site to the catalytic site. This study may provide an in-depth mechanism for abnormal activation and allosteric regulation of K-Ras4BG13D.

15.
Front Immunol ; 13: 851556, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35401512

RESUMO

PLX5622 is a CSF-1R inhibitor and microglia-depleting reagent, widely used to investigate the biology of this central nervous system (CNS)-resident myeloid population, but the indirect or off-target effects of this agent remain largely unexplored. In a murine model of severe neuroinflammation induced by West Nile virus encephalitis (WNE), we showed PLX5622 efficiently depleted both microglia and a sub-population of border-associated macrophages in the CNS. However, PLX5622 also significantly depleted mature Ly6Chi monocytes in the bone marrow (BM), inhibiting their proliferation and lethal recruitment into the infected brain, reducing neuroinflammation and clinical disease scores. Notably, in addition, BM dendritic cell subsets, plasmacytoid DC and classical DC, were depleted differentially in infected and uninfected mice. Confirming its protective effect in WNE, cessation of PLX5622 treatment exacerbated disease scores and was associated with robust repopulation of microglia, rebound BM monopoiesis and markedly increased inflammatory monocyte infiltration into the CNS. Monoclonal anti-CSF-1R antibody blockade late in WNE also impeded BM monocyte proliferation and recruitment to the brain, suggesting that the protective effect of PLX5622 is via the inhibition of CSF-1R, rather than other kinase targets. Importantly, BrdU incorporation in PLX5622-treated mice, suggest remaining microglia proliferate independently of CSF-1 in WNE. Our study uncovers significantly broader effects of PLX5622 on the myeloid lineage beyond microglia depletion, advising caution in the interpretation of PLX5622 data as microglia-specific. However, this work also strikingly demonstrates the unexpected therapeutic potential of this molecule in CNS viral infection, as well as other monocyte-mediated diseases.


Assuntos
Monócitos , Febre do Nilo Ocidental , Animais , Camundongos , Microglia , Compostos Orgânicos , Receptores de Fator Estimulador de Colônias/metabolismo , Índice de Gravidade de Doença
16.
Front Pharmacol ; 13: 862504, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35370687

RESUMO

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm, driven by the BCR-ABL1 fusion oncoprotein. The discovery of orthosteric BCR-ABL1 tyrosine kinase inhibitors (TKIs) targeting its active ATP-binding pocket, such as first-generation Imatinib and second-generation Nilotinib (NIL), has profoundly revolutionized the therapeutic landscape of CML. However, currently targeted therapeutics still face considerable challenges with the inevitable emergence of drug-resistant mutations within BCR-ABL1. One of the most common resistant mutations in BCR-ABL1 is the T315I gatekeeper mutation, which confers resistance to most current TKIs in use. To resolve such conundrum, co-administration of orthosteric TKIs and allosteric drugs offers a novel paradigm to tackle drug resistance. Remarkably, previous studies have confirmed that the dual targeting BCR-ABL1 utilizing orthosteric TKI NIL and allosteric inhibitor ABL001 resulted in eradication of the CML xenograft tumors, exhibiting promising therapeutic potential. Previous studies have demonstrated the cooperated mechanism of two drugs. However, the conformational landscapes of synergistic effects remain unclear, hampering future efforts in optimizations and improvements. Hence, extensive large-scale molecular dynamics (MD) simulations of wide type (WT), WT-NIL, T315I, T315I-NIL, T315I-ABL001 and T315I-ABL001-NIL systems were carried out in an attempt to address such question. Simulation data revealed that the dynamic landscape of NIL-bound BCR-ABL1 was significantly reshaped upon ABL001 binding, as it shifted from an active conformation towards an inactive conformation. The community network of allosteric signaling was analyzed to elucidate the atomistic overview of allosteric regulation within BCR-ABL1. Moreover, binding free energy analysis unveiled that the affinity of NIL to BCR-ABL1 increased by the induction of ABL001, which led to its favorable binding and the release of drug resistance. The findings uncovered the in-depth structural mechanisms underpinning dual-targeting towards T315I BCR-ABL1 to overcome its drug resistance and will offer guidance for the rational design of next generations of BCR-ABL1 modulators and future combinatory therapeutic regimens.

17.
Drug Discov Today ; 27(8): 2226-2234, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35314339

RESUMO

Allosteric modulators target topologically distal allosteric sites in order to modulate orthosteric sites, providing enhanced specificity and physiochemical properties. Harnessing allostery for drug discovery is an emerging paradigm in modern pharmaceutics. Allosteric regulation substantially depends on the propagation of allosteric signaling. Delineating allosteric signaling pathways is therefore one of the leading prerequisites for allosteric drug discovery. Allosteric signal transduction is subtle and dynamic, posing challenges for characterization through traditional experimental techniques, but computational strategies promise to provide a solution to this problem. Here, we comprehensively review bioinformatic methods for elucidating allosteric communication, along with their successful applications in allosteric drug design. Current challenges and future perspectives are also discussed. We aim to provide guidance for the future application and optimization of these computational strategies, thereby promoting rational allosteric drug discovery.


Assuntos
Desenho de Fármacos , Proteínas , Regulação Alostérica , Sítio Alostérico , Comunicação , Ligantes , Proteínas/metabolismo
18.
Comput Struct Biotechnol J ; 20: 1352-1365, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35356544

RESUMO

Argonaute (AGO) proteins, the core of RNA-induced silencing complex, are guided by microRNAs (miRNAs) to recognize target RNA for repression. The miRNA-target RNA recognition forms initially through pairing at the seed region while the additional supplementary pairing can enhance target recognition and compensate for seed mismatch. The extension of miRNA lengths can strengthen the target affinity when pairing both in the seed and supplementary regions. However, the mechanism underlying the effect of the supplementary pairing on the conformational dynamics and the assembly of AGO-RNA complex remains poorly understood. To address this, we performed large-scale molecular dynamics simulations of AGO-RNA complexes with different pairing patterns and miRNA lengths. The results reveal that the additional supplementary pairing can not only strengthen the interaction between miRNA and target RNA, but also induce the increased plasticity of the PAZ domain and enhance the domain connectivity among the PAZ, PIWI, N domains of the AGO protein. The strong community network between these domains tightens the mouth of the supplementary chamber of AGO protein, which prevents the escape of target RNA from the complex and shields it from solvent water attack. Importantly, the inner stronger matching pairs between the miRNA and target RNA can compensate for weaker mismatches at the edge of supplementary region. These findings provide guidance for the design of miRNA mimics and anti-miRNAs for both clinical and experimental use and open the way for further engineering of AGO proteins as a new tool in the field of gene regulation.

19.
Front Immunol ; 13: 784486, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35296081

RESUMO

Dietary fiber supports healthy gut bacteria and their production of short-chain fatty acids (SCFA), which promote anti-inflammatory cell development, in particular, regulatory T cells. It is thus beneficial in many diseases, including influenza infection. While disruption of the gut microbiota by antibiotic treatment aggravates West Nile Virus (WNV) disease, whether dietary fiber is beneficial is unknown. WNV is a widely-distributed neurotropic flavivirus that recruits inflammatory monocytes into the brain, causing life-threatening encephalitis. To investigate the impact of dietary fiber on WNV encephalitis, mice were fed on diets deficient or enriched with dietary fiber for two weeks prior to inoculation with WNV. To induce encephalitis, mice were inoculated intranasally with WNV and maintained on these diets. Despite increased fecal SCFA acetate and changes in gut microbiota composition, dietary fiber did not affect clinical scores, leukocyte infiltration into the brain, or survival. After the brain, highest virus loads were measured in the colon in neurons of the submucosal and myenteric plexuses. Associated with this, there was disrupted gut homeostasis, with shorter colon length and higher local inflammatory cytokine levels, which were not affected by dietary fiber. Thus, fiber supplementation is not effective in WNV encephalitis.


Assuntos
Febre do Nilo Ocidental , Vírus do Nilo Ocidental , Animais , Encéfalo/metabolismo , Citocinas/metabolismo , Fibras na Dieta , Camundongos , Vírus do Nilo Ocidental/fisiologia
20.
Acta Pharm Sin B ; 12(2): 876-889, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35256952

RESUMO

SIRT6 belongs to the conserved NAD+-dependent deacetylase superfamily and mediates multiple biological and pathological processes. Targeting SIRT6 by allosteric modulators represents a novel direction for therapeutics, which can overcome the selectivity problem caused by the structural similarity of orthosteric sites among deacetylases. Here, developing a reversed allosteric strategy AlloReverse, we identified a cryptic allosteric site, Pocket Z, which was only induced by the bi-directional allosteric signal triggered upon orthosteric binding of NAD+. Based on Pocket Z, we discovered an SIRT6 allosteric inhibitor named JYQ-42. JYQ-42 selectively targets SIRT6 among other histone deacetylases and effectively inhibits SIRT6 deacetylation, with an IC50 of 2.33 µmol/L. JYQ-42 significantly suppresses SIRT6-mediated cancer cell migration and pro-inflammatory cytokine production. JYQ-42, to our knowledge, is the most potent and selective allosteric SIRT6 inhibitor. This study provides a novel strategy for allosteric drug design and will help in the challenging development of therapeutic agents that can selectively bind SIRT6.

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