FOXO1 Promotes Wound Healing Through the Up-Regulation of TGF-β1 and Prevention of Oxidative Stress

Keratinocyte mobilization is a critical aspect of wound re-epithelialization, but the mechanisms that control its precise regulation remain poorly understood. We set out to test the hypothesis that forkhead box O1 (FOXO1) has a negative effect on healing because of its capacity to inhibit proliferation and promote apoptosis. Contrary to expectations, FOXO1 is required for keratinocyte transition to a wound-healing phenotype that involves increased migration and up-regulation of transforming growth factor β1 (TGF-β1) and its downstream targets, integrin-α3 and -β6 and MMP-3 and -9. Furthermore, we show that FOXO1 functions in keratinocytes to reduce oxidative stress, which is necessary to maintain cell migration and prevent cell death in a TGF-β1–independent manner. Thus, our studies identify a novel function for FOXO1 in coordinating the response of keratinocytes to wounding through up-regulation of TGF-β1 and other factors needed for keratinocyte migration and protection against oxidative stress, which together promote migration and decrease apoptosis

Ensayo metodológico de determinación de la heladicidad de hormigón estructural fabricado con árido reciclado

Esta comunicación presenta el ajuste de una metodología de determinación de la resistencia al hielodeshielo de hormigones estructurales fabricados con árido reciclado, la cual se está llevando a cabo por un grupo de trabajo integrado por profesores y estudiantes de las Escuelas Técnicas Superiores de Ingenieros de Minas e Industriales, de la Universidad Politécnica de Madrid, con el fin de evaluar la variación de las propiedades que sufren distintas dosificaciones de dichos hormigones cuando son sometidas a ensayos de heladicidad. Se realiza en primer lugar un estudio de la normativa existente, con el objetivo de definir tanto la duración de los ciclos como los criterios de degradación. Seguidamente se registra, mediante medidas de la velocidad de propagación de ultrasonidos las variaciones observadas en el hormigón. Al final de la puesta a punto de la técnica experimental se puede decir que se llegan a reproducir los ciclos de hielo-deshielo diseñados y se observa degradación del materia

FOXO1 Deletion Reduces Dendritic Cell Function and Enhances Susceptibility to Periodontitis

The host response plays both protective and destructive roles in periodontitis. FOXO1 is a transcription factor that is activated in dendritic cells (DCs), but its function in vivo has not been examined. We investigated the role of FOXO1 in activating DCs in experimental (CD11c.Cre+.FOXO1L/L) compared with matched control mice (CD11c.Cre−.FOXO1L/L) in response to oral pathogens. Lineage-specific FOXO1 deletion reduced the recruitment of DCs to oral mucosal epithelium by approximately 40%. FOXO1 was needed for expression of genes that regulate migration, including integrins αν and β3 and matrix metalloproteinase-2. Ablation of FOXO1 in DCs significantly decreased IL-12 produced by DCs in mucosal surfaces. Moreover, FOXO1 deletion reduced migration of DCs to lymph nodes, reduced capacity of DCs to induce formation of plasma cells, and reduced production of bacteria-specific antibody. The decrease in DC function in the experimental mice led to increased susceptibility to periodontitis through a mechanism that involved a compensatory increase in osteoclastogenic factors, IL-1β, IL-17, and RANKL. Thus, we reveal a critical role for FOXO1 in DC recruitment to oral mucosal epithelium and activation of adaptive immunity induced by oral inoculation of bacteria

Osteoblast Lineage Cells Play an Essential Role in Periodontal Bone Loss Through Activation of Nuclear Factor-Kappa B.

Bacterial pathogens stimulate periodontitis, the most common osteolytic disease in humans and the most common cause of tooth loss in adults. Previous studies identified leukocytes and their products as key factors in this process. We demonstrate for the first time that osteoblast lineage cells play a critical role in periodontal disease. Oral infection stimulated nuclear localization of NF-κB in osteoblasts and osteocytes in the periodontium of wild type but not transgenic mice that expressed a lineage specific dominant negative mutant of IKK (IKK-DN) in osteoblast lineage cells. Wild-type mice were also susceptible to bacteria induced periodontal bone loss but transgenic mice were not. The lack of bone loss in the experimental group was linked to reduced RANKL expression by osteoblast lineage cells that led to diminished osteoclast mediated bone resorption and greater coupled new bone formation. The results demonstrate that osteoblast lineage cells are key contributors to periodontal bone loss through an NF-κB mediated mechanism

Episodic memory dysfunction and hypersynchrony in brain functional networks in cognitively intact subjects and MCI: A study of 379 individuals

Delayed recall (DR) impairment is one of the most significant predictive factors in defining the progression to Alzheimer’s disease (AD). Changes in brain functional connectivity (FC) could accompany this decline in the DR performance even in a resting state condition from the preclinical stages to the diagnosis of AD itself, so the characterization of the relationship between the two phenomena has attracted increasing interest. Another aspect to contemplate is the potential moderator role of the APOE genotype in this association, considering the evidence about their implication for the disease. 379 subjects (118 mild cognitive impairment (MCI) and 261 cognitively intact (CI) individuals) underwent an extensive evaluation, including MEG recording. Applying cluster-based permutation test, we identified a cluster of differences in FC and studied which connections drove such an effect in DR. The moderation effect of APOE genotype between FC results and delayed recall was evaluated too. Higher FC in beta band in the right occipital region is associated with lower DR scores in both groups. A significant anteroposterior link emerged in the seed-based analysis with higher values in MCI. Moreover, APOE genotype appeared as a moderator between beta FC and DR performance only in the CI group. An increased beta FC in the anteroposterior brain region appears to be associated with lower memory performance in MCI. This finding could help discriminate the pattern of the progression of healthy aging to MCI and the relation between resting state and memory performance

Bacterial Infection Increases Periodontal Bone Loss in Diabetic Rats Through Enhanced Apoptosis

Periodontal disease is the most common osteolytic disease in humans and is significantly increased by diabetes mellitus. We tested the hypothesis that bacterial infection induces bone loss in diabetic animals through a mechanism that involves enhanced apoptosis. Type II diabetic rats were inoculated with Aggregatibacter actinomycetemcomitans and treated with a caspase-3 inhibitor, ZDEVD-FMK, or vehicle alone. Apoptotic cells were measured with TUNEL; osteoblasts and bone area were measured in H&E sections. New bone formation was assessed by labeling with fluorescent dyes and by osteocalcin mRNA levels. Osteoclast number, eroded bone surface, and new bone formation were measured by tartrate-resistant acid phosphatase staining. Immunohistochemistry was performed with an antibody against tumor necrosis factor-α. Bacterial infection doubled the number of tumor necrosis factor-α–expressing cells and increased apoptotic cells adjacent to bone 10-fold (P \u3c 0.05). Treatment with caspase inhibitor blocked apoptosis, increased the number of osteoclasts, and eroded bone surface (P \u3c 0.05); yet, inhibition of apoptosis resulted in significantly greater net bone area because of an increase in new bone formation, osteoblast numbers, and an increase in bone coupling. Thus, bacterial infection in diabetic rats stimulates periodontitis, in part through enhanced apoptosis of osteoblastic cells that reduces osseous coupling through a caspase-3–dependent mechanism. Diabetes is a chronic inflammatory disease characterized by hyperglycemia that affects 26 million Americans.1 Diabetes has several complications, such as cardiovascular, renal, microvascular, and periodontal diseases. Periodontal disease is one of the most common forms of osteolytic bone disease and one of the most frequent complications of the diabetes.2 Recent research suggests that the relationship between periodontitis and diabetes is reciprocal.3, 4 People with diabetes are more susceptible to periodontitis, and periodontitis may affect serum glucose levels and contribute to progression of diabetes.5 Diabetes may contribute to periodontitis because of its effect on inflammation.6, 7 Despite being triggered by bacterial infection, periodontal bone loss is tied to the inflammatory host response, which leads to the generation of prostaglandins and cytokines that stimulate osteoclastogenesis and periodontal bone loss.8 Several of the detrimental aspects of periodontal disease have recently been shown to be mediated by elevated levels of tumor necrosis factor-α (TNF-α).9, 10 TNF-α is a proinflammatory cytokine produced by leukocytes and other cell types.11 Enhanced TNF-α levels have been directly linked to cellular changes in diabetic retinopathy, deficits in wound healing, and diabetes-enhanced periodontitis.12, 13, 14 Some of the detrimental effects of diabetes-enhanced TNF-α levels may be because of the induction of cell death by triggering caspase activity. Caspases are a family of cysteine proteases that can act as either initiators (caspases 2, 8, and 9) or executioners (caspases 3, 6, and 7) of apoptosis.15 Caspase-3 appears to play a central role in bacteria and lipopolysaccharide-mediated apoptosis.16, 17 In addition, it has been shown that TNF-α can stimulate the expression of several pro-apoptotic genes, many of which are regulated by the pro-apoptotic transcription factor, forkhead box-O1 (FOXO1).18 The functional role of apoptosis in pathological processes can be studied with caspase inhibitors, which are small peptides that block the activity of well-defined caspases.19 These inhibitors have been used in animal models to attenuate cell death and diminish tissue damage in ischemic conditions, sepsis, and other pathological processes.20, 21 Other studies using caspase inhibitors have shown that part of the detrimental effect of diabetes on healing after infection is the result of increased fibroblast or osteoblast apoptosis.16, 22 To understand how diabetes may affect periodontal bone loss through apoptosis, we used a caspase-3/7 inhibitor in a type 2 Goto-Kakizaki (GK) diabetic rat model of periodontal disease induced by bacterial infection. The aim of this study was to determine how apoptosis of osteoblasts contributed to periodontal bone loss by its effect on bone formation in diabetic animals

NF-κB has a Direct Role in Inhibiting Bmp- and Wnt-Induced Matrix Protein Expression.

The host response to pathogens through nuclear factor κB (NF-κB) is an essential defense mechanism for eukaryotic organisms. NF-κB-mediated host responses inhibit bone and other connective tissue synthesis and are thought to affect the transcription of matrix proteins through multiple indirect pathways. We demonstrate that inhibiting NF-κB in osteoblasts increases osteocalcin expression in vivo in mice with periodontal disease. Mutating NF-κB binding sites on osteocalcin (OC) or bone sialoprotein (Bsp) promoters rescues the negative impact of NF-κB on their transcription and that NF-κB can inhibit Wnt- and Bmp-induced OC and Bsp transcription, even when protein synthesis is inhibited, indicating a direct effect of NF-κB. This inhibition depends on p65-p50 NF-κB heterodimer formation and deacetylation by HDAC1 but is not affected by the noncanonical NF-κB pathway. Moreover, NF-κB reduces Runx2 and β-catenin binding to OC/Bsp promoters independently of their nuclear localization. Thus, inflammatory signals stimulate the direct interaction of NF-κB with response elements to inhibit binding of β-catenin and Runx2 binding to nearby consensus sites and reduce expression of matrix proteins. This direct mechanism provides a new explanation for the rapid decrease in new bone formation after inflammation-related NF-κB activation

A.Actinomycetemcomitans‐Induced Periodontal Disease Promotes Systemic and Local Responses in Rat Periodontium

Aim To characterize the histologic and cellular response to A. actinomycetemcomitans (Aa) infection. Material & Methods Wistar rats infected with Aa were evaluated for antibody response, oral Aa colonization, loss of attachment, PMN recruitment, TNF‐α in the junctional epithelium and connective tissue, osteoclasts and adaptive immune response in local lymph nodes at baseline and 4, 5 or 6 weeks after infection. Some groups were given antibacterial treatment at 4 weeks. Results An antibody response against Aa occurred within 4 weeks of infection, and 78% of inoculated rats had detectable Aa in the oral cavity (p \u3c 0.05). Aa infection significantly increased loss of attachment that was reversed by antibacterial treatment (p \u3c 0.05). TNF‐α expression in the junctional epithelium followed the same pattern. Aa stimulated high osteoclast formation and TNF‐α expression in the connective tissue (p \u3c 0.05). PMN recruitment significantly increased after Aa infection (p \u3c 0.05). Aa also increased the number of CD8+ T cells (p \u3c 0.05), but not CD4+ T cells or regulatory T cells (Tregs) (p \u3e 0.05). Conclusion Aa infection stimulated a local response that increased numbers of PMNs and TNF‐α expression in the junctional epithelium and loss of attachment. Both TNF‐α expression in JE and loss of attachment was reversed by antibiotic treatment. Aa infection also increased TNF‐α in the connective tissue, osteoclast numbers and CD8+ T cells in lymph nodes. The results link Aa infection with important characteristics of periodontal destruction