RESUMEN
HucR is a MarR family protein of Deinococcus radiodurans, which binds tightly to the intergenic region of HucR and the uricase gene to inhibit their expression. Urate (or uric acid) antagonizes the repressor function of HucR by binding to HucR to impede its association with the cognate DNA. The previously reported crystal structure of HucR was without the bound urate showing significant structural homology to other MarR structures. In this paper, we report the crystal structure of HucR determined with the urate bound. However, despite the fact that the urate is found at a site well-known to harbor ligands in other MarR family proteins, the overall HucR structure indicates that no significant change in structure takes place with the urate bound. Structure analysis further suggests that the urate interaction in HucR is mediated by histidine/glutamate side chains and ordered water molecules stabilized by various residues. Such interaction is quite unique compared to other known structural interactions between urate and its binding proteins. Furthermore, structural comparison of the apo- and the urate bound forms allows us to hypothesize that the Trp20-mediated water network in the apo-form stabilizes the proper HucR fold for cognate DNA binding, and that urate binding, also via Trp20, and the consequent reorganization of water molecules in the binding pocket, likely disrupts the DNA binding configuration to result in the attenuated DNA binding.
Asunto(s)
Deinococcus , Proteínas Bacterianas/metabolismo , Cristalografía por Rayos X , ADN/química , Deinococcus/química , Unión Proteica , Ácido Úrico/metabolismo , Agua/metabolismoRESUMEN
Salmonella enterica serovar Typhimurium (S. Typhimurium) is a globally recognized foodborne pathogen that affects both animals and humans. Endoribonucleases mediate RNA processing and degradation in the adaptation of bacteria to environmental changes and have been linked to the pathogenicity of S. Typhimurium. Not much is known about the specific regulatory mechanisms of these enzymes in S. Typhimurium, particularly in the context of environmental adaptation. Thus, this study carried out a comparative transcriptomic analysis of wild-type S. Typhimurium SL1344 and its mutant (∆rnc), which lacks the rnc gene encoding RNase III, thereby elucidating the detailed regulatory characteristics that can be attributed to the rnc gene. Global gene expression analysis revealed that the ∆rnc strain exhibited 410 upregulated and 301 downregulated genes (fold-change > 1.5 and p < 0.05), as compared to the wild-type strain. Subsequent bioinformatics analysis indicated that these differentially expressed genes are involved in various physiological functions, in both the wild-type and ∆rnc strains. This study provides evidence for the critical role of RNase III as a general positive regulator of flagellar-associated genes and its involvement in the pathogenicity of S. Typhimurium.
Asunto(s)
Ribonucleasa III , Salmonella typhimurium , Humanos , Animales , Ribonucleasa III/genética , Ribonucleasa III/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Perfilación de la Expresión Génica , Transcriptoma , Regulación Bacteriana de la Expresión GénicaRESUMEN
In obesity, CD11c+ innate immune cells are recruited to adipose tissue and create an inflammatory state that causes both insulin and catecholamine resistance. We found that ablation of Gnas, the gene that encodes Gαs, in CD11c expressing cells protects mice from obesity, glucose intolerance, and insulin resistance. Transplantation studies showed that the lean phenotype was conferred by bone marrow-derived cells and did not require adaptive immunity. Loss of cAMP signaling was associated with increased adipose tissue norepinephrine and cAMP signaling, and prevention of catecholamine resistance. The adipose tissue had reduced expression of catecholamine transport and degradation enzymes, suggesting that the elevated norepinephrine resulted from decreased catabolism. Collectively, our results identified an important role for cAMP signaling in CD11c+ innate immune cells in whole-body metabolism by controlling norepinephrine levels in white adipose tissue, modulating catecholamine-induced lipolysis and increasing thermogenesis, which, together, created a lean phenotype. ARTICLE HIGHLIGHTS: We undertook this study to understand how immune cells communicate with adipocytes, specifically, whether cAMP signaling in the immune cell and the adipocyte are connected. We identified a reciprocal interaction between CD11c+ innate immune cells and adipocytes in which high cAMP signaling in the immune cell compartment induces low cAMP signaling in adipocytes and vice versa. This interaction regulates lipolysis in adipocytes and inflammation in immune cells, resulting in either a lean, obesity-resistant, and insulin-sensitive phenotype, or an obese, insulin-resistant phenotype.
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Dieta Alta en Grasa , Resistencia a la Insulina , Obesidad , Animales , Ratones , Tejido Adiposo Blanco/metabolismo , Catecolaminas/metabolismo , Dieta Alta en Grasa/efectos adversos , Insulina/metabolismo , Resistencia a la Insulina/fisiología , Ratones Endogámicos C57BL , Norepinefrina/metabolismo , Obesidad/etiología , Obesidad/metabolismoRESUMEN
Henoch-Schönlein purpura (HSP) is an IgA-mediated small vessel vasculitis with a predominant cutaneous involvement. We assessed adult patients with HSP to identify the clinical and histopathological features and evaluate predictive factors of relapse. We reviewed the records of 29 adult patients with HSP who presented at our department between 2002 and 2009. Adult HSP was confirmed by skin biopsy showing leukocytoclastic vasculitis and direct immunofluorescence showing IgA deposit. Among the 29 patients (15 men, 14 women; mean age 36.2 years old), renal involvement was initially found in 22 patients (75.9%). They were divided into 2 groups according to the presence or absence of relapse. We compared clinical and histopathologic differences between 15 patients with relapse and 14 patients without relapse. By univariate analysis, older age at onset, persistent rash, abdominal pain, hematuria, and underlying disease at the onset of HSP are significantly related to relapse. Among the histopathological variables, severity of leukocytoclasis and absence of IgM deposit on the vessel walls are significantly associated to relapsing disease (P < 0.05). Our results are significant, because, they may help to understand the predictive factors related to relapses of HSP in adults. Further studies are necessary to identify whether more aggressive treatment in adults with HSP with these predictive factors can prevent relapse and severe renal sequelae.
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Vasculitis por IgA/patología , Adulto , Factores de Edad , Comorbilidad , Femenino , Técnica del Anticuerpo Fluorescente , Humanos , Vasculitis por IgA/epidemiología , Masculino , Pronóstico , Recurrencia , Estudios RetrospectivosAsunto(s)
Antituberculosos/efectos adversos , Erupciones por Medicamentos/etiología , Erupciones Liquenoides/inducido químicamente , Mucosa Bucal/efectos de los fármacos , Piel/efectos de los fármacos , Tuberculosis Pulmonar/tratamiento farmacológico , Corticoesteroides/uso terapéutico , Erupciones por Medicamentos/diagnóstico , Erupciones por Medicamentos/tratamiento farmacológico , Antagonistas de los Receptores Histamínicos/uso terapéutico , Humanos , Erupciones Liquenoides/diagnóstico , Erupciones Liquenoides/tratamiento farmacológico , Masculino , Persona de Mediana Edad , Mucosa Bucal/patología , Piel/patología , Resultado del Tratamiento , Tuberculosis Pulmonar/diagnósticoRESUMEN
Mutation of leucine-rich repeat kinase 2 (LRRK2) causes an autosomal dominant and late-onset familial Parkinson's disease (PD). Recently, we reported that LRRK2 directly binds to and phosphorylates the threonine 474 (T474)-containing Thr-X-Arg(Lys) (TXR) motif of focal adhesion kinase (FAK), thereby inhibiting the phosphorylation of FAK at tyrosine (Y) 397 residue (pY397-FAK), which is a marker of its activation. Mechanistically, however, it remained unclear how T474-FAK phosphorylation suppressed FAK activation. Here, we report that T474-FAK phosphorylation could inhibit FAK activation via at least two different mechanisms. First, T474 phosphorylation appears to induce a conformational change of FAK, enabling its N-terminal FERM domain to autoinhibit Y397 phosphorylation. This is supported by the observation that the levels of pY397-FAK were increased by deletion of the FERM domain and/or mutation of the FERM domain to prevent its interaction with the kinase domain of FAK. Second, pT474-FAK appears to recruit SHP-2, which is a phosphatase responsible for dephosphorylating pY397-FAK. We found that mutation of T474 into glutamate (T474E-FAK) to mimic phosphorylation induced more strong interaction with SHP-2 than WT-FAK, and that pharmacological inhibition of SHP-2 with NSC-87877 rescued the level of pY397 in HEK293T cells. These results collectively show that LRRK2 suppresses FAK activation through diverse mechanisms that include the promotion of autoinhibition and/or the recruitment of phosphatases, such as SHP-2.
RESUMEN
In response to brain injury, microglia rapidly extend processes that isolate lesion sites and protect the brain from further injury. Here we report that microglia carrying a pathogenic mutation in the Parkinson's disease (PD)-associated gene, G2019S-LRRK2 (GS-Tg microglia), show retarded ADP-induced motility and delayed isolation of injury, compared with non-Tg microglia. Conversely, LRRK2 knockdown microglia are highly motile compared with control cells. In our functional assays, LRRK2 binds to focal adhesion kinase (FAK) and phosphorylates its Thr-X-Arg/Lys (TXR/K) motif(s), eventually attenuating FAK activity marked by decreased pY397 phosphorylation (pY397). GS-LRRK2 decreases the levels of pY397 in the brain, microglia and HEK cells. In addition, treatment with an inhibitor of LRRK2 kinase restores pY397 levels, decreased pTXR levels and rescued motility of GS-Tg microglia. These results collectively suggest that G2019S mutation of LRRK2 may contribute to the development of PD by inhibiting microglial response to brain injury.
Asunto(s)
Lesiones Encefálicas , Movimiento Celular/genética , Proteína-Tirosina Quinasas de Adhesión Focal/metabolismo , Microglía/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Cicatrización de Heridas/genética , Animales , Western Blotting , Proteína-Tirosina Quinasas de Adhesión Focal/antagonistas & inhibidores , Técnicas de Silenciamiento del Gen , Células HEK293 , Humanos , Inmunoprecipitación , Proteína 2 Quinasa Serina-Treonina Rica en Repeticiones de Leucina , Ratones , Ratones Transgénicos , Mutación , Fosforilación , Proteínas Serina-Treonina Quinasas/metabolismo , RatasRESUMEN
BACKGROUND: New antitumor therapeutic strategies aim to combine different approaches that are able to induce tumor-specific effector and memory T cell responses that might control tumor growth. Dendritic cells (DCs) have the capacity to induce antigen-specific cytotoxic T lymphocytes. We have previously shown that the combined treatment of paclitaxel chemotherapy (Chemo) and injection of DCs led to complete tumor regression. OBJECTIVE: The goal of this study was to evaluate synergistic antitumor effect of a triple combination treatment comprising radiotherapy, paclitaxel Chemo and intratumoral injection of syngeneic bone marrow-derived DCs on murine fibrosarcoma, compared to other single or double combination treatments. METHODS: For the murine fibrosarcoma model, naïve C57BL/6 mice were inoculated intradermally with 2×10(3) MCA102 cells in the right upper flank. Mice were assigned to five groups (untreatedcontrol, RT alone, RT+Chemo, RT+DC, and RT+Chemo+DC), with eight mice in each group. In vitro cytotoxicity assays were performed to assess the immune activity. The persistence of tumor-specific immunity was determined by second tumor challenge in mice with complete tumor regression. RESULTS: The triple combination treatment showed a significantly enhanced therapeutic efficacy by decreasing tumor size and inducing complete tumor regression, resulting in a cure of 50% of mice. The results of in vitro cytotoxicity assays and the second tumor challenge experiment strongly indicated the induction of a tumor-specific cytotoxic T lymphocyte response and acquisition of prolonged tumor immunity. CONCLUSION: These findings suggest that the triple combination treatment can be a promising strategy for the treatment of murine fibrosarcoma.
RESUMEN
Parkinson's disease (PD) is the second most common neurodegenerative motor disease caused by degeneration of dopaminergic neurons in the substantia nigra. Because brain inflammation has been considered a risk factor for PD, we analyzed whether PTEN induced putative kinase 1 (PINK1), an autosomal recessive familial PD gene, regulates brain inflammation during injury states. Using acutely prepared cortical slices to mimic injury, we analyzed expression of the pro-inflammatory cytokines tumor necrosis factor-α, interleukin (IL)-1ß, and IL-6 at the mRNA and protein levels. Both mRNA and protein expression of these cytokines was higher at 6-24 h after slicing in PINK1 knockout (KO) slices compared to that in wild-type (WT) slices. In serial experiments to understand the signaling pathways that increase inflammatory responses in KO slices, we found that IκB degradation was enhanced but Akt phosphorylation decreased in KO slices compared to those in WT slices. In further experiments, an inhibitor of PI3K (LY294002) upstream of Akt increased expression of pro-inflammatory cytokines. Taken together, these results suggest that PINK1 deficiency enhance brain inflammation through reduced Akt activation and enhanced IκB degradation in response to brain injury.
RESUMEN
BACKGROUND: Androgenetic alopecia (AGA) is a common hair loss disease with genetic predisposition among men and women, and it may commence at any age after puberty. It may significantly affect a variety of psychological and social aspects of one's life and the individual's overall quality of life (QoL). OBJECTIVE: This study aimed to investigate the QoL of AGA patients and discover the factors that can influence the QoL of AGA patients, including previous experience in non-medical hair care, reasons for hospital visits, age, duration, and the severity of AGA. METHODS: A total of 998 male patients with AGA were interviewed, using the Hair Specific Skindex-29 to evaluate the QoL of AGA patients. RESULTS: The results of the Hair Specific Skindex-29 on patients with AGA were as follows: symptom scale: 26.3±19.5, function scale: 24.0±20.1, emotion scale: 32.1±21.8, and global score: 27.3±19.1. According to this assessment, QoL was more damaged if the patient had severe alopecia, a longer duration of AGA, younger age, had received previous non-medical hair care, and visited the hospital for AGA treatment. CONCLUSION: This study showed that AGA could harmfully affect the patients' QoL. These findings indicate that dermatologists should address these QoL issues when treating patients with alopecia.