Silent information regulator 2 proteins encoded by Cryptosporidium parasites

Novel Synthetic Approaches for Bisnaphthalimidopropyl (BNIP) Derivatives as Potential Anti-Parasitic Agents for the Treatment of Leishmaniasis

Leishmaniasis is a neglected parasitic disease that is widely seen in more than 60 countries worldwide, including Turkey and its subcontinental region. There are several chemotherapy agents for the treatment of leishmaniasis, including pentavalent antimonials—i.e., sodium stibogluconate (Pentostan) and meglumine antimoniate (Glucantim), pentamidine, conventional amphotericin B deoxycholate, miltefosine, paramomycin (aminosidine), and liposomal amphotericin B. However, these therapies are usually unsatisfactory due to dose-limiting toxicity issues and limited efficacy. Furthermore, resistance gained by parasites endangers future success of these therapies. Addressing these issues, the development of novel drugs with high efficacy has a vital importance. Latest studies have shown that bisnaphthalimidopropyl (BNIP) derivatives display high activity against Leishmaniasis parasites by selectively targeting parasitic sirtuin proteins and interacting with DNA. Despite the promising anti-parasitic activity, the low solubility and toxicity on human macrophages are the limitations to overcome. This study describes the new synthesis strategies for existing—i.e., BNIPDaoct and BNIPDanon—and novel BNIP derivatives differing in respect of their alkyl linker chain lengths. The new synthesis approach provides certain advantages compared to its existing alternatives reported in the literature. The proposed methodology does not only decrease the number of synthesis steps and production time of BNIPDaoct and BNIPDanon, but also provides higher yields, thereby making the synthesis highly cost-effective.

Sirtuins of parasitic protozoa: in search of function(s)

The SIR2 family of NAD⁺-dependent protein deacetylases, collectively called sirtuins, has been of central interest due to their proposed roles in life-span regulation and ageing. Sirtuins are one group of environment sensors of a cell interpreting external information and orchestrating internal responses at the sub-cellular level, through participation in gene regulation mechanisms. Remarkably conserved across all kingdoms of life SIR2 proteins in several protozoan parasites appear to have both conserved and intriguing unique functions. This review summarises our current knowledge of the members of the sirtuin families in Apicomplexa, including Plasmodium, and other protozoan parasites such as Trypanosoma and Leishmania. The wide diversity of processes regulated by SIR2 proteins makes them targets worthy of exploitation in anti-parasitic therapies.

Sirtuin mechanism and inhibition: explored with N(ε)-acetyl-lysine analogs

Silent information regulator 2 (Sir2) enzymes or sirtuins are a family of intracellular protein deacetylases that can catalyze the β-nicotinamide adenine dinucleotide (β-NAD(+))-dependent deacetylation of N(ε)-acetyl-lysine on protein substrates, with the formation of lysine N(ε)-deacetylated protein species and small molecule products, i.e. nicotinamide and 2'-O-acetyl-ADP-ribose (2'-O-AADPR). These enzymes are evolutionarily conserved among all the three kingdoms of life, with the yeast Sir2 being the founding family member. In humans, seven sirtuins, i.e. SIRT1-7, have been identified. The past a few years have witnessed a tremendous interest in investigating the unique mechanism for the sirtuin-catalyzed deacetylation reaction. We have also seen a lot of research employing different strategies to identify different types of the inhibitors for this enzymatic deacetylation reaction. These inhibitors hold great potential toward a fuller exploration of sirtuin biology and pharmacology as well as toward developing novel therapeutics for metabolic and age-related diseases and cancer. Here we would like to review the significant contributions that the judicious use of a variety of N(ε)-acetyl-lysine analogs has been able to make toward our enhanced mechanistic understanding and capability of pharmacological exploitation of the sirtuin-catalyzed deacetylation reaction.