Basic mechanisms of lymphocyte recirculation in Lewis rats

Development of grape polyphenols as multi-targeting strategies for Alzheimer's disease

Alzheimer's disease (AD) is by far the most prevalent neurodegenerative disease of aging and is a major burden for patients, caregivers, and the overall health care system. The complexity of AD pathophysiology and the lack of deep understanding of disease mechanisms impeded the development of AD therapy. Currently approved treatments for AD only modestly improve cognitive function but do not modify disease course. The lack of pharmacological approaches has led to the consideration of alternative strategies to prevent or to slow down the progression of AD. There has been a growing interest in the scientific community regarding the impact of diet and nutrition on AD. Grape derived nutraceuticals and phytochemical compounds have demonstrated anti-amyloidogenic, antioxidative, anti-inflammatory and neurotrophic properties and present as potential novel strategies for AD treatment. In this review, we summarize promising grape derived polyphenols that have been shown to modulate AD pathophysiology including amyloid plaques and neurofibrillary tangles formation, AD-induced oxidative stress, neuroinflammation and synaptic dysfunction.

Mutations of Cx43 that affect B cell spreading in response to BCR signaling

The gap junction (GJ) protein connexin 43 (Cx43) is both necessary and sufficient for B cell receptor (BCR)-mediated cell spreading. To address how Cx43 mediates this effect, we blocked its function genetically, by expressing mutants of Cx43, and pharmacologically, by using chemical inhibitors. While various point mutations of Cx43 inhibited B cell spreading, treatment with channel blocking drugs did not, suggesting that this response was independent of channel function. The critical region of Cx43 appears to be the cytoplasmic carboxyl-terminal (CT) domain, which has previously been shown to be important for B cell spreading. Consistent with this, mutations of either tyrosine 247 or 265 found in the CT were sufficient to inhibit spreading. Thus Cx43 may influence B cell spreading by mechanisms requiring protein binding to, or modification of, these sites in the CT tail.

Effect of Fever-Like Whole-Body Hyperthermia on Lymphocyte Spectrin Distribution, Protein Kinase C Activity, and Uropod Formation

Regional inflammation and systemic fever are hallmarks of host immune responses to pathogenic stimuli. Although the thermal element of fever is thought to enhance the activity of immune effector cells, it is unclear what the precise role of increased body temperatures is on the activation state and effector functions of lymphocytes. We report here that mild, fever-like whole body hyperthermia (WBH) treatment of mice results in a distinct increase in the numbers of tissue lymphocytes with polarized spectrin cytoskeletons and uropods, as visualized in situ. WBH also induces a coincident reorganization of protein kinase C (PKC) isozymes and increased PKC activity within T cells. These hyperthermia-induced cellular alterations are nearly identical with the previously described effects of Ag- and mitogen-induced activation on lymphocyte spectrin and PKC. Immunoprecipitation studies combined with dual staining and protein overlay assays confirmed the association of PKCβ and PKCθ with spectrin following its reorganization. The receptor for activated C kinase-1 was also found to associate with the spectrin-based cytoskeleton. Furthermore, all these molecules (spectrin, PKCβ, PKCθ, and receptor for activated C kinase-1) cotranslocate to the uropod. Enhanced intracellular spectrin phosphorylation upon WBH treatment of lymphocytes was also found and could be blocked by the PKC inhibitor bisindolylmaleimide I (GF109203X). These data suggest that the thermal element of fever, as mimicked by these studies, can modulate critical steps in the signal transduction pathways necessary for effective lymphocyte activation and function. Further work is needed to determine the cellular target(s) that transduces the signaling pathway(s) induced by hyperthermia.