Antifungal activity of Cardiospermum halicacabum L. (Sapindaceae) against Trichophyton rubrum occurs through molecular interaction with fungal Hsp90.

INTRODUCTION: Dermatophytosis is a superficial fungal infection limited to the stratum corneum of the epidermis, or to the hair and nails, and constitutes an important public health problem because of its high prevalence and associated morbidity. Dermatophyte fungi, especially 2 species, Trichophyton rubrum and Trichophyton mentagrophytes, are the predominant pathogens. Topical antifungal drugs, mainly azoles or allyamines, are currently used for the treatment of dermatophytoses, although in some cases, such as in nail and hair involvement, systemic treatment is required. However, therapeutic efficacy of current antifungal agents can be limited by their side effects, costs, and the emergence of drug resistance among fungi. Plant extracts represent a potential source of active antimicrobial agents, due to the presence of a variety of chemical bioactive compounds. In the present work, we evaluated in silico and in vitro the antifungal activity of an extract of the medicinal plant Cardiospermum halicacabum against T. rubrum suggesting a potential interaction with Hsp90 as playing an important role in both pathogenicity and drug susceptibility of T. rubrum. METHODS: We investigated in vitro the effect of different concentrations of C. halicacabum (from 500 to 31.25 µg) against a clinical isolate of T. rubrum. Furthermore, using a computational assessment, the interaction between different C. halicacabum active compounds and the fungal Hsp90 was also investigated. RESULTS: Our results indicate a clear-cut antifungal activity of the total plant extract at the highest concentrations (500 and 250 µg). Among all tested C. halicacabum compounds, the luteolin and rutin molecules have been identified in silico as the most important potential inhibitors of Hsp90. Based on these data, luteolin and rutin were also individually assessed for their antifungal activity. Results demonstrate that both substances display an antifungal effect, even if lower than that of the total plant extract. CONCLUSION: Our data indicate a strong fungistatic effect of C. halicacabum against T. rubrum, suggesting its potential therapeutic efficacy in the treatment of dermatophytoses. Additionally, C. halicacabum compounds, and particularly luteolin and rutin, are all possible Hsp90 interactors, explaining their fungistatic activity.

Historical review on thymosin α1 in oncology: preclinical and clinical experiences.

INTRODUCTION: Thymosin α1 (Tα1) is a naturally occurring polypeptide that regulates immune cell development and function, and is also capable of interacting with multiple target cells with relevant biological effects. The rationale of Tα1 use in cancer treatment stems from the consideration that tumor progression is favored by a failure of the immune response and in turn induces immune suppression. This paper will review the historical background of Tα1 use in oncology, aiming to highlight the importance of Tα1 as an immunotherapeutic tool to be used in combination with chemotherapy, a concept that is not yet fully established in clinic. AREAS COVERED: The efficacy and safety of combining Tα1 with chemotherapy and cytokines were first evaluated in murine tumor models, providing essential information about effects, mechanisms of action, doses and treatment protocols. The therapeutic potential of the chemo-immunotherapy protocol on metastatic melanoma and lung cancer has been confirmed in controlled clinical trials. Critical for the efficacy of the chemo-immunotherapy protocol is the dual action of Tα1 on immune effector and tumor cells. EXPERT OPINION: On the basis of the preclinical and clinical results available, the use of the chemo-immunotherapy protocol, in which the role of Tα1 is central, is strongly recommended.

Increased levels of p70S6 phosphorylation in the G93A mouse model of Amyotrophic Lateral Sclerosis and in valine-exposed cortical neurons in culture.

The higher risk factor for Amyotrophic Lateral Sclerosis (ALS) among Italian soccer players is a question that is still debated. One of the hypotheses that have been formulated to explain a possible link between ALS and soccer players is related to the abuse of dietary supplements and drugs for enhancing sporting performance. In particular, it has been reported that branched-chain amino acids (BCAAs) are widely used among athletes as nutritional supplements. To observe the possible effect of BCAAs on neuronal electrical properties, we performed electrophysiological experiments on Control cultured cortical neurons and on neurons after BCAA treatment. BCAA-treated neurons showed hyperexcitability and rapamycin was able to suppress it and significantly reduce the level of mTOR, Akt and p70S6 phosphorylation. Interestingly, the hyperexcitability previously reported in cortical neurons from a genetic mouse model of ALS (G93A) was also reversed by rapamycin treatment. Moreover, both G93A and valine-treated neurons presented significantly higher levels of Pp70S6 when compared to control neurons, strongly indicating the involvement of this substrate in ALS pathology. Finally, we performed electrophysiological experiments on motor cortex slices from Control and G93A mice and those fed with a BCAA-enriched diet. We observed that neuron excitability was comparable between G93A and BCAA-enriched diet mice, but was significantly higher than in Control mice. These findings, besides strongly indicating that BCAAs specifically induce hyperexcitability, seem to suggest the involvement of p70S6 substrate in ALS pathology.