FOXO1 plays an important role in enhanced microvascular cell apoptosis and microvascular cell loss in type 1 and type 2 diabetic rats.

Objective: To investigate early events leading to microvascular cell loss in diabetic retinopathy.

Research Design And Methods: FOXO1 was tested in vivo by DNA binding activity and by nuclear translocation in microvascular cells in retinal trypsin digests. In vivo studies were undertaken in STZ-induced diabetic rats and Zucker diabetic fatty rats using the tumor necrosis factor (TNF)-specific blocker, pegsunercept, or by inhibiting FOXO1 with RNAi.

Activation of the acquired immune response reduces coupled bone formation in response to a periodontal pathogen.

Osteoimmunolgy involves the interaction of the immune system with skeletal elements. This interaction can lead to the formation of osseous lesions. To investigate how the acquired immune response could contribute to osteolytic lesions, we injected the periodontal pathogen Porphyromonas gingivalis adjacent to calvarial bone with or without prior immunization against the bacterium.

P. gingivalis and E. coli lipopolysaccharides exhibit different systemic but similar local induction of inflammatory markers.

Background: Porphyromonas gingivalis is a Gram-negative bacterium that is an important etiologic agent of human adult periodontitis. The goal of the study was to test the hypothesis that two isoforms of P. gingivalis lipopolysaccharide (PgLPS), PgLPS(1435)(/1449) and PgLPS(1690), exhibit differences in their capacity to stimulate systemic versus local responses compared to Escherichia coli lipopolysaccharide (LPS).

Diabetes-enhanced tumor necrosis factor-alpha production promotes apoptosis and the loss of retinal microvascular cells in type 1 and type 2 models of diabetic retinopathy.

Retinal microvascular cell loss plays a critical role in the pathogenesis of diabetic retinopathy. To examine this further, type 1 streptozotocin-induced diabetic rats and type 2 Zucker diabetic fatty rats were treated by intravitreal injection of the tumor necrosis factor-specific inhibitor pegsunercept, and the impact was measured by analysis of retinal trypsin digests. For type 2 diabetic rats, the number of endothelial cells and pericytes positive for diabetes-enhanced activated caspase-3 decreased by 81% and 86%, respectively, when treated with pegsunercept (P < 0.

Fibroblast apoptosis induced by Porphyromonas gingivalis is stimulated by a gingipain and caspase-independent pathway that involves apoptosis-inducing factor.

Porphyromonas gingivalis is an oral bacterium that causes pathology in a number of dental infections that are associated with increased fibroblast cell death. Studies presented here demonstrated that P. gingivalis stimulates cell death by apoptosis rather than necrosis.

Immunization enhances inflammation and tissue destruction in response to Porphyromonas gingivalis.

It is well established that host-bacterium interactions play a critical role in the initiation and progression of periodontal diseases. By the use of inhibitors, it has been shown that mediators associated with the innate immune response significantly contribute to the disease process. Less is known regarding the role of the acquired immune response.

Tumor necrosis factor-alpha mediates diabetes-enhanced apoptosis of matrix-producing cells and impairs diabetic healing.

Diabetics suffer increased infection followed by increased apoptosis of fibroblasts and bone-lining cells during the healing process. To investigate a potential mechanism, we inoculated Porphyromonas gingivalis into the scalp of type 2 diabetic (db/db) or control mice and inhibited tumor necrosis factor alpha (TNF-alpha) with etanercept. Mice were euthanized at the early phase of infection (21 hours) or during the peak repair of the bacteria-induced wound (8 days).

Diabetes enhances mRNA levels of proapoptotic genes and caspase activity, which contribute to impaired healing.

We previously reported that after a bacteria-induced wound in the scalp, type 2 diabetic (db/db) mice had higher levels of apoptosis of fibroblasts and bone-lining cells that are critical for healing compared with normoglycemic controls. To investigate mechanisms by which this might occur, RNA profiling and caspase activity was measured after inoculation of Porphyromonas gingivalis. Diabetes caused a more than twofold induction of 71 genes that directly or indirectly regulate apoptosis and significantly enhanced caspase-8, -9, and -3 activity.

Porphyromonas gingivalis fimbriae are pro-inflammatory but do not play a prominent role in the innate immune response to P. gingivalis.

The fimA gene encodes the major fimbrial protein of Porphyromonas gingivalis. It has been shown to stimulate adhesion to salivary proteins and other bacteria. It is also thought to play a major role in invading and stimulating host cells.

Cytokine profiling of macrophages exposed to Porphyromonas gingivalis, its lipopolysaccharide, or its FimA protein.

To characterize the roles of Porphyromonas gingivalis and its components in the disease processes, we investigated the cytokine profile induced by live P. gingivalis, its lipopolysaccharides (LPS), and its major fimbrial protein, fimbrillin (FimA). Using cytokine antibody arrays, we found that P.

Diabetes prolongs the inflammatory response to a bacterial stimulus through cytokine dysregulation.

Diabetes has been identified as an important risk factor for infection. But relatively little is known about how diabetes alters the inflammatory response to bacteria. The objective of this study was to investigate how diabetes affects host-bacteria interactions by focusing on the inflammatory response in a connective tissue setting.

Diabetes alters the response to bacteria by enhancing fibroblast apoptosis.

Diabetics suffer from both more frequent bacterial infections and greater consequences of infection. However, bacteria-induced tissue destruction and the subsequent response in diabetics have received relatively little attention. To investigate this issue, we inoculated the scalp of control or db/db diabetic mice, with the pathogen Porphyromonas gingivalis, which causes connective tissue destruction in humans.

Diabetes causes decreased osteoclastogenesis, reduced bone formation, and enhanced apoptosis of osteoblastic cells in bacteria stimulated bone loss.

The most common cause of inflammatory bone loss is periodontal disease. After bacterial insult, inflammation induces bone resorption, which is followed by new reparative bone formation. Because diabetics have a higher incidence and more severe periodontitis, we examined mechanisms by which diabetes alters the response of bone to bacterial challenge.