Transient expression of OCT4 is sufficient to allow human keratinocytes to change their differentiation pathway

In this study, we describe a simple system in which human keratinocytes can be redirected to an alternative differentiation pathway. We transiently transfected freshly isolated human skin keratinocytes with the single transcription factor OCT4. Within 2 days these cells displayed expression of endogenous embryonic genes and showed reduced genomic methylation. More importantly, these cells could be specifically converted into neuronal and contractile mesenchymal cell types. Redirected differentiation was confirmed by expression of neuronal and mesenchymal cell mRNA and protein, and through a functional assay in which the newly differentiated mesenchymal cells contracted collagen gels as efficiently as authentic myofibroblasts. Thus, to generate patient-specific cells for therapeutic purposes, it may not be necessary to completely reprogram somatic cells into induced pluripotent stem cells before altering their differentiation and grafting them into new tissues.

Intestinal helminths protect in a murine model of asthma

Underdeveloped nations are relatively protected from the worldwide asthma epidemic; the hygiene hypothesis suggests this is due to suppression of Th2-mediated inflammation by increased exposure to pathogens and their products. Although microbial exposures can promote Th2-suppressing Th1 responses, even Th2-skewing infections, such as helminths, appear to suppress atopy, suggesting an alternate explanation for these observations. To investigate whether induction of regulatory responses by helminths may counter allergic inflammation, we examined the effects of helminth infection in a murine model of atopic asthma. We chose Heligosomoides polygyrus, a gastrointestinal nematode, as the experimental helminth; this worm does not enter the lung in its life cycle. We found that H. polygyrus infection suppressed allergen-induced airway eosinophilia, bronchial hyperreactivity, and in vitro allergen-recall Th2 responses in an IL-10-dependent manner; total and OVA-specific IgE, however, were increased by worm infection. Finally, helminth-infected mice were protected against eosinophilic inflammation induced by adoptive transfer of OVA-stimulated CD4(+) cells, and transfer of cells from helminth-infected/OVA-exposed mice suppressed OVA-induced eosinophilic inflammation, suggesting a role for regulatory cells. Increased CD4(+)CD25(+)Foxp3(+) cells were found in thoracic lymph nodes of helminth-infected/OVA-exposed mice. Helminthic colonization appears to protect against asthma and atopic disorders; the regulatory cytokine, IL-10, may be a critical player.

Toxic epidermal necrolysis-like acute cutaneous lupus erythematosus and the spectrum of the acute syndrome of apoptotic pan-epidermolysis (ASAP): a case report, concept review and proposal for new classification of lupus erythematosus vesiculobullous skin lesions

The acute clinical syndrome of toxic epidermal necrolysis (TEN) is currently thought to be a distinct clinical-pathological entity typically resulting from drug hypersensitivity. We describe an adult woman who experienced a fulminate pattern of apoptotic epidermal cell injury following tanning bed exposure while taking naproxen that resulted in a clinical presentation having combined features of drug-induced TEN and an infrequently recognized form of bullous cutaneous lupus erythematosus (LE). This case calls attention to the fact that TEN-like injury can occasionally be seen in settings other than drug hypersensitivity (e.g., LE, acute graft versus host disease) and illustrates the need for a unifying concept in this area. We therefore propose the term 'Acute Syndrome of Apoptotic Pan-Epidermolysis (ASAP)' to designate a clinical syndrome that is characterized by life-threatening acute and massive cleavage of the epidermis resulting from hyperacute apoptotic injury of the epidermis. We also review vesiculobullous skin disorders that can be encountered in LE patients and suggest a new classification scheme for such lesions.