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Most botulinum toxin A (BoNT-A) products for esthetic use require reconstitution before administration. Ready-to-use relabotulinumtoxinA is a liquid manufactured using Precipitation-free Extraction and Activity-preserving, Refined Liquid (PEARL^TM) Technology from a proprietary C. botulinum type A1 strain. We examined the in vitro characteristics of relabotulinumtoxinA. The specific BoNT-A1 potency remained consistent throughout drug substance manufacturing (1.9 x 10⁸-2.2 x 10⁸ LD₅₀ mouse potency units/mg of BoNT-A1, four fractions sampled). Using glabellar line (GL) on-label doses, relabotulinumtoxinA liquid product was compared with powder onabotulinumtoxinA using the following: BoNT-A1 amount based on ELISA; specific enzyme activity based on SNAP-25 cleavage by a fluorescence resonance energy transfer-based assay (BoTest^®); biological activity (binding, internalization, and SNAP-25 cleavage over time) using a cell-based assay. RelabotulinumtoxinA contained more BoNT-A1 per on-label GL dose (0.27 ng) than onabotulinumtoxinA (0.18 ng), had higher enzyme activity (53 vs. 29 BoTest^® units) per GL dose, and had higher specific activity per pg BoNT-A, with onabotulinumtoxinA displaying 81% of the specific activity of relabotulinumtoxinA. In vitro, relabotulinumtoxinA demonstrated higher biological activity and earlier onset of SNAP-25-cleavage than onabotulinumtoxinA. PEARL^TM Technology thus produces high-quality BoNT-A1 with high specific enzyme and biological activities, which may explain the clinical performance of relabotulinumtoxinA in Phase 3 clinical trials examining treatment of GLs and/or LCLs.

Introduction

Statins, widely used for hypercholesterolemia, have shown anticancer properties including induction of apoptosis and ferroptosis, modulation of autophagy, and reprogramming of the tumor microenvironment, making them potential candidates for repurposing in cancer therapy. Although growing evidence suggests that statins may influence kinase signaling, current data remain inconclusive. To better understand this potential mechanism, we investigated the impact of statins on kinase activity.

Methods

We employed an integrative approach combining publicly available RNA-seq and phosphoproteomic datasets with in vitro kinome inhibition profiling. The study assessed the effects of atorvastatin, simvastatin, and cerivastatin across a panel of 400 kinases. Western blot was used to assess whether reduced PI3K phosphorylation was due to mevalonate depletion.

Results

Our analyses revealed that statins primarily influence kinase signaling via alterations in phosphorylation rather than through transcriptional regulation or direct inhibition. Phosphoproteomic data showed a general reduction in kinase phosphorylation, although some kinases exhibited increased activity. Affected kinases were significantly enriched in cancer-associated pathways, including insulin signaling, EGF-EGFR signaling, PI3K/AKT signaling, and the PD-L1/PD-1 immune checkpoint axis. Direct inhibition was observed for two kinases: CAMK1G (IC50 = 8.9 mu M) and TSSK1B (IC50 = 3.3 mu M). In colorectal cancer cell lines, decreased PI3K phosphorylation was at least partially attributable to mevalonate depletion, a known consequence of statin treatment.Discussion These findings suggest that the anticancer activity of statins may be mediated, at least in part, through their ability to modulate kinase phosphorylation and activity. This mechanistic insight supports further exploration of statins as modulators of kinase signaling in oncology.

Neurodevelopmental studies employing animal models encounter challenges due to interspecies differences and ethical concerns. Maturing neurons of human origin, undergoing several developmental stages, present a powerful alternative. In this study, human embryonic stem cell (H9 cell line) was differentiated into neural stem cells and subsequently matured into neurons over 30 days. Ion AmpliSeq^TM was used for transcriptomic characterization of human stem cell-derived neurons at multiple time points. Data analysis revealed a progressive increase of markers associated with neuronal development and astrocyte markers, indicating the establishment of a co-culture accommodating both glial and neurons. Transcriptomic and pathway enrichment analysis also revealed a more pronounced GABAergic phenotype in the neurons, signifying their specialization toward this cell type. The findings confirm the robustness of these cells across different passages and demonstrate detailed progression through stages of development. The model is intended for neurodevelopmental applications and can be adapted to investigate how genetic modifications or exposure to chemicals, pharmaceuticals, and other environmental factors influence neurons and glial maturation.

Background/Objectives: Many pregnant women globally suffer from depression and are routinely prescribed selective serotonin reuptake inhibitors (SSRIs). These drugs function by blocking the re-uptake of serotonin by the serotonin transporter (SERT) into neurons, resulting in its accumulation in the presynaptic cleft. Despite a large amount of research suggesting a potential link to neurodevelopmental disorders in children whose mothers took these drugs during pregnancy, their possible adverse effects are still debated, and results are contradictory. On the other hand, there is an immediate need for improved cell-based models for developmental neurotoxicity studies (DNT) to minimize the use of animals in research.

Methods: In this study, we aimed to assess the effects of clinically relevant concentrations of paroxetine (PAR), fluoxetine (FLX), and citalopram (CIT)-on maturing neurons derived from human neural stem cells using multiple endpoints.

Results: Although none of the tested concentrations of FLX, CIT, or PAR significantly affected cell viability, FLX (10 mu M) exhibited the highest reduction in viability compared to the other drugs. Regarding neurite outgrowth, CIT did not have a significant effect. However, FLX (10 mu M) significantly reduced both mean neurite outgrowth and mean processes, PAR significantly reduced mean processes, and showed a trend of dysregulation of multiple genes associated with neuronal development at therapeutic-relevant serum concentrations.

Conclusions: Transcriptomic data and uptake experiments found no SERT activity in the system, suggesting that the adverse effects of FLX and PAR are independent of SERT.

Exposure to microgravity (μg) results in a range of systemic changes in the organism, but may also have beneficial cellular effects. In a previous study we detected increased proliferation capacity and upregulation of genes related to proliferation and survival in boundary cap neural crest stem cells (BC) after MASER14 sounding rocket flight compared to ground-based controls. However, whether these changes were due to μg or hypergravity was not clarified. In the current MASER15 experiment BCs were exposed simultaneously to μg and 1 g conditions provided by an onboard centrifuge. BCs exposed to μg displayed a markedly increased proliferation capacity compared to 1 g on board controls, and genetic analysis of BCs harvested 5 h after flight revealed an upregulation, specifically in μg-exposed BCs, of Zfp462 transcription factor, a key regulator of cell pluripotency and neuronal fate. This was associated with alterations in exosome microRNA content between μg and 1 g exposed MASER15 specimens. Since the specimens from MASER14 were obtained for analysis with 1 week’s delay, we examined whether gene expression and exosome content were different compared to the current MASER15 experiments, in which specimens were harvested 5 h after flight. The overall pattern of gene expression was different and Zfp462 expression was down-regulated in MASER14 BC μg compared to directly harvested specimens (MASER15). MicroRNA exosome content was markedly altered in medium harvested with delay compared to directly collected samples. In conclusion, our analysis indicates that even short exposure to μg alters gene expression, leading to increased BC capacity for proliferation and survival, lasting for a long time after μg exposure. With delayed harvest of specimens, a situation which may occur due to special post-flight circumstances, the exosome microRNA content is modified compared to fast specimen harvest, and the direct effects from μg exposure may be partially attenuated, whereas other effects can last for a long time after return to ground conditions.

Previously, we showed that fluvastatin treatment induces myofibrillar damage and mitochondrial phenotypes in the skeletal muscles of Drosophila. However, the sequential occurrence of mitochondrial phenotypes and myofibril damage remains elusive. To address this, we treated flies with fluvastatin for two and five days and examined their thorax flight muscles using confocal microscopy. In the two-day fluvastatin group, compared to the control, thorax flight muscles exhibited mitochondrial morphological changes, including fragmentation, rounding up and reduced content, while myofibrils remained organized in parallel. In the five-day fluvastatin treatment, not only did mitochondrial morphological changes become more pronounced, but myofibrils became severely disorganized with significantly increased thickness and spacing, along with myofilament abnormalities, suggesting myofibril damage. These findings suggest that fluvastatin-induced mitochondrial changes precede myofibril damage. Moreover, in the five-day fluvastatin group, the mitochondria demonstrated elevated H₂O₂ and impaired fatty acid oxidation compared to the control group, indicating potential mitochondrial dysfunction. Surprisingly, knocking down Hmgcr (Drosophila homolog of HMGCR) showed normal mitochondrial respiration in all parameters compared to controls or five-day fluvastatin treatment, which suggests that fluvastatin-induced mitochondrial dysfunction might be independent of Hmgcr inhibition. These results provide insights into the sequential occurrence of mitochondria and myofibril damage in statin-induced myopathy for future studies.

Background and Purpose

Statins are competitive inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (HMGCR), and exert adverse effects on mitochondrial function, although the mechanisms underlying these effects remain unclear. We used a tamoxifen-induced Hmgcr-knockout (KO) mouse model, a multi-omics approach and mitochondrial function assessments to investigate whether decreased HMGCR activity impacts key liver energy metabolism pathways.

Experimental Approach

We established a new mouse strain using the Cre/loxP system, which enabled whole-body deletion of Hmgcr expression. These mice were crossed with Rosa26^Cre mice and treated with tamoxifen to delete Hmgcr in all cells. We performed transcriptomic and metabolomic analyses and thus evaluated time-dependent changes in metabolic functions to identify the pathways leading to cell death in Hmgcr-KO mice.

Key Results

Lack of Hmgcr expression resulted in lethality, due to acute liver damage caused by rapid disruption of mitochondrial fatty acid β-oxidation and very high accumulation of long-chain (LC) acylcarnitines in both male and female mice. Gene expression and KO-related phenotype changes were not observed in other tissues. The progression to liver failure was driven by diminished peroxisome formation, which resulted in impaired mitochondrial and peroxisomal fatty acid metabolism, enhanced glucose utilization and whole-body hypoglycaemia.

Conclusion and Implications

Our findings suggest that HMGCR is crucial for maintaining energy metabolism balance, and its activity is necessary for functional mitochondrial β-oxidation. Moreover, statin-induced adverse reactions might be rescued by the prevention of LC acylcarnitine accumulation.

Statins are one of the most important classes of drugs. In this analytical review, we elucidate the intricate molecular mechanisms and toxicological rationale regarding both the on- (targeting 3-hydroxy-3-methylglutaryl-coenzyme A reductase [HMGCR]) and off-target effects of statins. Statins interact with a number of membrane kinases, such as epidermal growth factor receptor (EGFR), erb-b2 receptor tyrosine kinase 2 (HER2) and MET proto-oncogene, receptor tyrosine kinase (MET), as well as cytosolic kinases, such as SRC proto-oncogene, non-receptor tyrosine kinase (Src) and show inhibitory activity at nanomolar concentrations. In addition, they interact with calcium ATPases and peroxisome proliferator-activated receptor α (PPARα/NR1C1) at higher concentrations. Statins interact with mitochondrial complexes III and IV, and their inhibition of coenzyme Q10 synthesis also impairs the functioning of complexes I and II. Statins act as inhibitors of kinases, calcium ATPases and mitochondrial complexes, while activating PPARα. These off-target effects likely contribute to the side effects observed in patients undergoing statin therapy, including musculoskeletal symptoms and hepatic effects. Interestingly, some off-target effects of statins could also be the cause of favourable outcomes, relating to repurposing statins in conditions such as inflammatory disorders and cancer.

The blood-brain barrier (BBB) poses major challenges to drug delivery to the CNS. SFTI-1 and kalata B1 are cyclic cell-penetrating peptides (cCPPs) with high potential to be used as scaffolds for drug delivery. We here studied their transport across the BBB and distribution within the brain to gauge the potential of these two cCPPs as scaffolds for CNS drugs. In a rat model, SFTI-1 exhibited, for a peptide, high extent of BBB transport with a partitioning of unbound SFTI-1 across the BBB, K-p,K-uu,K-brain, of 13%, while only 0.5% of kalata B1 equilibrated across the BBB. By contrast, kalata B1, but not SFTI-1, readily entered neural cells. SFTI-1, but not kalata B1, could be a potential CNS delivery scaffold for drugs directed to extracellular targets. These findings indicate that differences between the BBB transport and cellular uptake abilities of CPPs are crucial in the development of peptide scaffolds.

Dipeptidyl peptidase 4 (DPP4) inhibitors, commonly known as gliptins, have been an integral part of the treatment of type 2 diabetes mellitus (T2DM) for several years. Despite their remarkable efficacy in lowering glucose levels and their compatibility with other hypoglycemic drugs, recent studies have revealed adverse effects, prompting the search for improved drugs within this category, which has required the use of animal models to verify the hypoglycemic effects of these compounds. Currently, in many countries the use of mammals is being significantly restricted, as well as cost prohibitive, and alternative in vivo approaches have been encouraged. In this sense, Drosophila has emerged as a promising alternative for several compelling reasons: it is cost-effective, offers high experimental throughput, is genetically manipulable, and allows the assessment of multigenerational effects, among other advantages. In this study, we present evidence that diprotin A, a DPP4 inhibitor, effectively reduces glucose levels in Drosophila hemolymph. This discovery underscores the potential of Drosophila as an initial screening tool for novel compounds directed against DPP4 enzymatic activity.