Isoflavonoids from Brazilian red propolis down-regulate the expression of cancer-related target proteins: A pharmacogenomic analysis.

Vestitol and neovestitol are bioactive isoflavonoids isolated from Brazilian red propolis, a unique Apis melifera type of propolis botanically originated from Dalbergia ecastophyllum. Although these molecules have relevant biological effects, including anticancer and immunomodulatory activities, their mechanism(s) of action and the affected pathways remain largely unknown. Here, we carried out a pharmacogenomic analysis to investigate the effects of vestitol and neovestitol on the whole-genome expression in human tumor cells, particularly cancer-related target proteins. HeLa cells were exposed to the compounds at IC20 and genomic information of treated cells was analyzed using the Illumina transcriptome system and GeneGo MetaCore software. Our results showed that vestitol (IC20  = 214.7 µM) reduced the expression of genes enrolled with the alpha tubulin (fold -3.7), tubulin in microtubules (fold -3.7), and histone h3 (fold = -3.03), and that treatment with neovestitol (IC20  = 102.91 µM) downregulated prostaglandin E synthase gene (fold = -3.12), which are considered ideal targets for anticancer therapy. These data open avenues for the study of vestitol and neovestitol as potential promising candidates for anticancer therapy. Toxicological, non-clinical, and clinical validation of the findings presented herein is needed.

Microtubule-associated proteins and enzymes modifying tubulin.

Microtubules (MTs) are essential for many cellular processes including establishment of cell shape and polarity, chromosome segregation, vesicle transport, and nuclear positioning. Human cells express 22 tubulin isoforms that have both overlapping and distinctive functions. Tubulins reversely polymerize to form cylindrical MTs, while MT-associated proteins (MAPs), posttranslational modifications (PTMs), and mechanical forces regulate their functions. To help both tubulin researchers and medicinal chemists, this review article lists 489 MAPs, 43 known enzymes that mediate PTMs, and 306 drugs that influence the functions of MTs and MAPs and discusses recent microtubule research. Readers are able to sort the list based on name, size, functions, related human diseases, and date of discovery. The list also contains links to Uniprot and Protein Atlas databases to access further details such as protein structure, associated proteins, subcellular localization, expression levels in cells and tissues, mutations, and pathology. Because the microtubule cytoskeleton is involved in many pathological processes such as tumorigenesis, invasion, and developmental diseases, small molecules that target on MT and MAPs hold potential to treat these diseases and are also listed.

SARM1 Depletion Slows Axon Degeneration in a CNS Model of Neurotropic Viral Infection.

Zika virus (ZIKV) is a neurotropic flavivirus recently linked to congenital ZIKV syndrome in children and encephalitis and Guillain-Barré syndrome in adults. Neurotropic viruses often use axons to traffic to neuronal or glial cell somas where they either remain latent or replicate and proceed to infect new cells. Consequently, it has been suggested that axon degeneration could represent an evolutionarily conserved mechanism to limit viral spread. Whilst it is not known if ZIKV transits in axons, we previously reported that ZIKV infection of glial cells in a murine spinal cord-derived cell culture model of the CNS is associated with a profound loss of neuronal cell processes. This, despite that postmitotic neurons are relatively refractory to infection and death. Here, we tested the hypothesis that ZIKV-associated degeneration of neuronal processes is dependent on activation of Sterile alpha and armadillo motif-containing protein 1 (SARM1), an NADase that acts as a central executioner in a conserved axon degeneration pathway. To test this, we infected wild type and Sarm1 homozygous or heterozygous null cell cultures with ZIKV and examined NAD+ levels as well as the survival of neurons and their processes. Unexpectedly, ZIKV infection led to a rapid SARM1-independent reduction in NAD+. Nonetheless, the subsequent profound loss of neuronal cell processes was SARM1-dependent and was preceded by early changes in the appearance of ß-tubulin III staining. Together, these data identify a role for SARM1 in the pathogenesis of ZIKV infection, which may reflect SARM1's conserved prodegenerative function, independent of its NADase activity.

Alpha-Tubulin Acetylation in Trypanosoma cruzi: A Dynamic Instability of Microtubules Is Required for Replication and Cell Cycle Progression.

Trypanosomatids have a cytoskeleton arrangement that is simpler than what is found in most eukaryotic cells. However, it is precisely organized and constituted by stable microtubules. Such microtubules compose the mitotic spindle during mitosis, the basal body, the flagellar axoneme and the subpellicular microtubules, which are connected to each other and also to the plasma membrane forming a helical arrangement along the central axis of the parasite cell body. Subpellicular, mitotic and axonemal microtubules are extensively acetylated in Trypanosoma cruzi. Acetylation on lysine (K) 40 of α-tubulin is conserved from lower eukaryotes to mammals and is associated with microtubule stability. It is also known that K40 acetylation occurs significantly on flagella, centrioles, cilia, basal body and the mitotic spindle in eukaryotes. Several tubulin posttranslational modifications, including acetylation of K40, have been cataloged in trypanosomatids, but the functional importance of these modifications for microtubule dynamics and parasite biology remains largely undefined. The primary tubulin acetyltransferase was recently identified in several eukaryotes as Mec-17/ATAT, a Gcn5-related N-acetyltransferase. Here, we report that T. cruzi ATAT acetylates α-tubulin in vivo and is capable of auto-acetylation. TcATAT is located in the cytoskeleton and flagella of epimastigotes and colocalizes with acetylated α-tubulin in these structures. We have expressed TcATAT with an HA tag using the inducible vector pTcINDEX-GW in T. cruzi. Over-expression of TcATAT causes increased levels of the alpha tubulin acetylated species, induces morphological and ultrastructural defects, especially in the mitochondrion, and causes a halt in the cell cycle progression of epimastigotes, which is related to an impairment of the kinetoplast division. Finally, as a result of TcATAT over-expression we observed that parasites became more resistant to microtubule depolymerizing drugs. These results support the idea that α-tubulin acetylation levels are finely regulated for the normal progression of T. cruzi cell cycle.