Using trehalose delivered by the intramuscular injection of plasmid DNA as an adjuvant for transgene expression

Trehalose maintains vitality of mouse epididymal epithelial cells and mediates gene transfer

In the present study, trehalose was utilized to improve primary culture of mouse epididymal epithelial cells in vitro, and to enhance naked DNA delivery in epididymis in vivo. During the six-day culture, the proliferation activity of the cells in the medium with addition of trehalose was higher than that of those cells cultured in absence of trehalose (p<0.01). To determine the optimal concentration for cell proliferation, a series of trehalose concentrations (0, 60, 120, 180 mM) were tested, and the result indicated that the cell in the medium with 120 mM trehalose showed the highest proliferation potential. The epididymis epithelial cells were cultured in the medium containing 120 mM trehalose upon 16^th passage, and they continued expressing markers of epididymal epithelial cell, such as rE-RABP, AR and ER-beta. Our study also indicated that trehalose concentrations of 120–240 mM, especially 180 mM, could effectively enhance DNA delivery into the mouse epididymis epithelial cell in vitro. Moreover, trehalose could induce in vivo expression of exogenous DNA in epididymal epithelial cells and help to internalize plasmid into sperm,which did not influence motility of sperm when the mixture of trehalose (180 mM) and DNA was injected into epididymal lumen through efferent tubule. This study suggested that trehalose, as an effective and safer reagent, could be employed potentially to maintain vitality of mouse epididymal epthetial cells during long-term culture in vitro and to mediate in vitro and in vivo gene transfer.

The importance of implementing proper selection of excipients in lupus clinical trials

Peptide therapeutics hold attractive potential. However, the proper stabilization of such therapeutics remains a major challenge. Some peptides are marginally stable and are prone to degradation. Therefore, in addition to chemical modifications that can be introduced in their sequence, a wide variety of excipients are added in the formulation to stabilize them, as is also done routinely for protein therapeutics. These substances are supposed to suppress peptide/protein aggregation and surface adsorption, facilitate their dispersion and additionally to provide physiological osmolality. Particular attention has to be paid to the choice of such excipients. Here we highlight the observation that in certain clinical situations, an excipient that is not totally inert can play a highly damaging role and mask (or even reverse) the beneficial effect of a molecule in clinical evaluation. This is the case, for instance, of trehalose, a normally safe excipient, which notably has proven to act as an activator of autophagy. This excipient, although used efficiently in several therapeutics, adversely impacted a phase IIb clinical trial for human and murine lupus, a systemic autoimmune disease in which it has been recently discovered that at the base line, autophagy is already abnormally enhanced in lymphocytes. Thus, in this particular pathology, while the peptide that was tested was active in lupus patients when formulated in mannitol, it was not efficient when formulated in trehalose. This observation is important, since autophagy is enhanced in a variety of pathological situations, such as obesity, diabetes, certain neurological diseases, and cancer.