Tirbanibulin (KX2-391) analog KX2-361 inhibits botulinum neurotoxin serotype A mediated SNAP-25 cleavage in pre- and post-intoxication models in cells.

Botulinum neurotoxins (BoNT) inhibit neuroexocytosis, leading to the potentially lethal disease botulism. BoNT serotype A is responsible for most human botulism cases, and there are no approved therapeutics to treat already intoxicated patients. A growing body of research has demonstrated that BoNT/A can escape into the central nervous system, and therefore, identification of BoNT/A inhibitors that can penetrate BBB and neutralize the toxin within intoxicated neurons would be important. We previously identified an FDA-approved, orally bioavailable compound, KX2-391 (Tirbanibulin) that inhibits BoNT/A in motor neuron assays. Recently, a structural analog of KX2-391, KX2-361, has been shown to exhibit good oral bioavailability and cross BBB with high efficiency in mouse experiments. Therefore, in this work, we evaluated the inhibitory effects of KX2-361 against BoNT/A. Toward this goal, we first evaluated the compound for its effects on cell viability in PC12 cells, via MTT assay, and in mouse embryonic stem cell (mESC)-derived motor neurons, with imaging-based assays. Following, we tested KX2-361 in mESC-derived motor neurons intoxicated with BoNT/A holotoxin, and the compound exhibited activity against the toxin in both pre- and post-intoxication conditions. Excitingly, KX2-361 also inhibited BoNT/A enzymatic component (light chain; LC) in PC12 cells transfected with BoNT/A LC. Furthermore, our molecular docking analyses suggested that KX2-361 can directly bind to BoNT/A LC. Medicinal chemistry approaches to develop structural analogs of KX2-361 to increase its efficacy against BoNT/A may provide a critical lead compound with BBB penetration capacity for drug development efforts against BoNT/A intoxication.

Generation and characterization of human induced pluripotent stem cell line METUi002-A from a patient with primary familial brain calcification (PFBC) carrying a heterozygous mutation (c.687dupT (p.Val230CysfsTer28)) in the SLC20A2 gene.

Primary familial brain calcification (PFBC) is a rare neurological condition characterized by abnormal calcification commonly in basal ganglia and multiple other brain regions, leading to neuropsychiatric, cognitive, and motor symptoms. SLC20A2, one of the known causative genes for PFBC, contains the highest number of variants directly associated with the disease. Here, we established an iPSC line (METUi002-A) from the peripheral blood mononuclear cells of a clinically diagnosed PFBC patient carrying a SLC20A2 mutation (c.687dupT) using the integration-free Sendai reprogramming. METUi002-A can serve as a valuable tool to generate cellular models to investigate the mechanistic effects of this mutation in PFBC.

Determination of radiological hazard parameters in sea snails (Rapana venosa) in the East Black Sea Coast of Turkey.

The aim of this study was to determine the activity concentrations and radiological hazard parameters of 137Cs and 40K in soft tissue samples of sea snails (Rapana venosa) collected from 12 different stations in the East Black Sea coastal area of Turkey. The values in soft tissues of sea snail samples with three different sizes were between 0.31 and 1.79 Bq kg-1 for 137Cs and 163.9 and 269.4 Bq kg-1 for 40K. The mean activity concentrations of 137Cs and 40K in tissues of small-sized sea snails were determined to be higher than those of 137Cs and 40K in soft tissues of the other sizes. The determined activity concentration values were lower than the concentrations reported in similar studies. Radiological hazard parameters such as the daily intake (Dint) of 137Cs and 40K, annual committed effective dose (Eeff), and lifetime cancer risk (LCR) were calculated and compared with the international recommended values.

RanBPM (RanBP9) regulates mouse c-Kit receptor level and is essential for normal development of bone marrow progenitor cells.

c-Kit is a tyrosine kinase receptor important for gametogenesis, hematopoiesis, melanogenesis and mast cell biology. Dysregulation of c-Kit function is oncogenic and its expression in the stem cell niche of a number of tissues has underlined its relevance for regenerative medicine and hematopoietic stem cell biology. Yet, very little is known about the mechanisms that control c-Kit protein levels. Here we show that the RanBPM/RanBP9 scaffold protein binds to c-Kit and is necessary for normal c-Kit protein expression in the mouse testis and subset lineages of the hematopoietic system. RanBPM deletion causes a reduction in c-Kit protein but not its mRNA suggesting a posttranslational mechanism. This regulation is specific to the c-Kit receptor since RanBPM reduction does not affect other membrane proteins examined. Importantly, in both mouse hematopoietic system and testis, RanBPM deficiency causes defects consistent with c-Kit loss of expression suggesting that RanBPM is an important regulator of c-Kit function. The finding that this regulatory mechanism is also present in human cells expressing endogenous RanBPM and c-Kit suggests a potential new strategy to target oncogenic c-Kit in malignancies.

TrkA in vivo function is negatively regulated by ubiquitination.

TrkA is a tyrosine kinase receptor required for development and survival of the peripheral nervous system. In the adult, TrkA and its ligand NGF are peripheral pain mediators, particularly in inflammatory pain states. However, how TrkA regulates the function of nociceptive neurons and whether its activity levels may lead to sensory abnormalities is still unclear. Here we report the characterization of a 3 aa (KFG) domain that negatively regulates TrkA level and function in response to NGF. Deletion of this domain in mouse causes a reduction of TrkA ubiquitination leading to an increase in TrkA protein levels and activity. The number of dorsal root ganglia neurons is not affected by the mutation. However, mutant mice have enhanced thermal sensitivity and inflammatory pain. Together, these data suggest that ubiquitination is a mechanism used in nociceptive neurons to regulate TrkA level and function. Our results may enhance our understanding of how ubiquitination affects TrkA activation following noxious thermal stimulation and inflammatory pain.