Polycyclic aromatic hydrocarbons regulate the pigmentation pathway and induce DNA damage responses in keratinocytes, a process driven by systemic immunity.

Background: Urban pollution is correlated with an increased prevalence of skin pigmentation disorders, however the physiological processes underlying this association are unclear.

Objectives: To delineate the relationship between polycyclic aromatic hydrocarbons (PAHs), a key constituent of atmospheric pollution, and immunity/skin pigmentation pathways.

Methods: We exposed peripheral blood mononuclear cells (PBMC) to PAHs and performed cytokines/chemokine profiling.

Glycosaminoglycans: Sweet as Sugar Targets for Topical Skin Anti-Aging.

Glycosaminoglycans (GAGs) are long, linear polysaccharides comprised of repeating disaccharide units with pleiotropic biological functions, with the non-sulfated GAG hyaluronic acid (HA), and sulfated GAGs dermatan sulfate, chondroitin sulfate, heparan sulfate, keratan sulfate, and to a lesser extent heparin all being expressed in skin. Their ability to regulate keratinocyte proliferation and differentiation, inflammatory processes and extracellular matrix composition and quality demonstrates their critical role in regulating skin physiology. Similarly, the water-binding properties of GAGs and structural qualities, particularly for HA, are crucial for maintaining proper skin form and hydration.

Distal airway stem cells yield alveoli in vitro and during lung regeneration following H1N1 influenza infection.

The extent of lung regeneration following catastrophic damage and the potential role of adult stem cells in such a process remains obscure. Sublethal infection of mice with an H1N1 influenza virus related to that of the 1918 pandemic triggers massive airway damage followed by apparent regeneration. We show here that p63-expressing stem cells in the bronchiolar epithelium undergo rapid proliferation after infection and radiate to interbronchiolar regions of alveolar ablation.