Advances in Aerosol Formulation for Targeted Delivery of Therapeutic Agents from Nose to Brain

The intricate anatomical and physiological barriers that prohibit pharmaceuticals from entering the brain continue to provide a noteworthy hurdle to the efficient distribution of medications to brain tissues. These barriers prevent the movement of active therapeutic agents into the brain. The present manuscript aims to describe the various aspects of brain-targeted drug delivery through the nasal route. The primary transport mechanism for drug absorption from the nose to the brain is the paracellular/extracellular mechanism, which allows for rapid drug transfer. The transcellular/intracellular pathway involves the transfer across a lipoidal channel, which regulates the entry or exit of anions, organic cations, and peptides. Spectroscopy and PET (positron emission tomography) are two common methods used for assessing drug distribution. MRI (Magnetic resonance imaging) is another imaging method used to assess the efficacy of aerosol drug delivery from nose to brain. It can identify emphysema, drug-induced harm, mucus discharge, oedema, and vascular remodeling. The olfactory epithelium's position in the nasal cavity makes it difficult for drugs to reach the desired target. Bi-directional aerosol systems and tools like the "OptiNose" can help decrease extranasal particle deposition and increase particle deposition efficiency in the primary nasal pathway. Direct medicine administration from N-T-B, however, can reduce the dose administered and make it easier to attain an effective concentration at the site of activity, and it has the potential to be commercialized.

Adjunctive Immunotherapeutic Efficacy of N-Formylated Internal Peptide of Mycobacterial Glutamine Synthetase in Mouse Model of Tuberculosis

BACKGROUND

Host-directed therapies are a comparatively new and promising method for the treatment of tuberculosis. A variety of host pathways, vaccines and drugs have the potential to provide novel adjunctive therapies for the treatment of tuberculosis. In this connection, we have earlier reported the immunotherapeutic potential of N-formylated N-terminal peptide of glutamine synthetase of Mycobacterim tuberculosis H37Rv (Mir SA and Sharma S, 2014). Now in the present study, we investigated the immunotherapeutic effect of N-terminally formylated internal-peptide 'f- MLLLPD' of mycobacterial glutamine synthetase (Rv2220) in mouse model of tuberculosis.

METHODS

The N-terminally formylated peptide, f-MLLLPD was tested for its potential to generate Reactive Oxygen Species (ROS) in murine neutrophils. Further, its therapeutic effect alone or in combination with anti-tubercular drugs was evaluated in mouse model of tuberculosis.

RESULTS

The f-MLLLPD peptide treatment alone and in combination with ATDs reduced the bacterial load (indicated as colony forming units) in lungs of infected mice by 0.58 (p<0.01) and 2.92 (p<0.001) log10 units respectively and in their spleens by 0.46 (p<0.05) and 2.46 (p<0.001) log10 units respectively. In addition, the observed histopathological results correlated well with the CFU data.

CONCLUSION

The results of the current study show that f-MLLLPD peptide confers an additional therapeutic efficacy to the anti-tuberculosis drugs.

Downregulation of SIRT7 by 5-fluorouracil induces radiosensitivity in human colorectal cancer

5-Fluorouracil (5-FU) combined with radiotherapy is a common treatment strategy to treat human cancers, but the underlying mechanisms of this combination treatment remain unclear. Here, we report that NAD⁺-dependent deacetylase sirtuin-7 (SIRT7) protein levels were decreased due to 5-FU exposure rendering colorectal cancer cells sensitive to radiation. We found that SIRT7 downregulation was mediated via a Tat-binding Protein 1 (TBP1) proteasome-dependent pathway. Specifically, TBP1 was dephosphorylated at tyrosine 381 upon 5-FU treatment, which enhanced its direct interaction with SIRT7 and targeted it for degradation. Depletion of SIRT7 in cultured colorectal cancer cells induced radiosensitivity triggering cell death. Interestingly, decreased levels of SIRT7 mediated by 5-FU correlated well with improved therapeutic effect in patients with rectal cancer and with inhibited tumor growth in immune-compromised mice post-irradiation. Taken together, these data suggest that 5-FU induces radiosensitivity via SIRT7 degradation to favor a cell death pathway in targeted cancer cells. Thus, downregulation of SIRT7 could be a promising pharmacologic strategy to increase the effectiveness of chemoradiation therapy in cancer patients.