Latrunculin A and its C-17-O-carbamates inhibit prostate tumor cell invasion and HIF-1 activation in breast tumor cells

The marine-derived macrolides latrunculins A ( 1) and B, from the Red Sea sponge Negombata magnifica, have been found to reversibly bind actin monomers, forming a 1:1 complex with G-actin and disrupting its polymerization. The microfilament protein actin is responsible for several essential functions within the cell such as cytokinesis and cell migration. One of the main binding pharmacophores of 1 to G-actin was identified as the C-17 lactol hydroxyl moiety that binds arginine 210 NH. Latrunculin A-17- O-carbamates 2- 6 were prepared by reaction with the corresponding isocyanates. Latrunculin A ( 1) and carbamates 4- 6 displayed potent anti-invasive activity against the human highly metastatic human prostate cancer PC-3M cells in a Matrigel assay at a concentration range of 50 nM to 1 microM. Latrunculin A ( 1, 500 nM) decreased the disaggregation and cell migration of PC-3M-CT+ spheroids by 3-fold. Carbamates 4 and 5 were 2.5- and 5-fold more active than 1, respectively, in this assay with less actin binding affinity. Latrunculin A ( 1, IC 50 6.7 microM) and its 17- O-[ N-(benzyl)carbamate ( 6, IC 50 29 microM) suppress hypoxia-induced HIF-1 activation in T47D breast tumor cells.

Pharmacogenetics of pain and analgesia

Pain severity ratings and the analgesic dosing requirements of patients with apparently similar pain conditions may differ considerably between individuals. Contributing factors include those of genetic and environmental origin with epigenetic mechanisms that enable dynamic gene-environment interaction, more recently implicated in pain modulation. Insight into genetic factors underpinning inter-patient variability in pain sensitivity has come from rodent heritability studies as well as familial aggregation and twin studies in humans. Indeed, more than 350 candidate pain genes have been identified as potentially contributing to heritable differences in pain sensitivity. A large number of genetic association studies conducted in patients with a variety of clinical pain types or in humans exposed to experimentally induced pain stimuli in the laboratory setting, have examined the impact of single-nucleotide polymorphisms in various target genes on pain sensitivity and/or analgesic dosing requirements. However, the findings of such studies have generally failed to replicate or have been only partially replicated by independent investigators. Deficiencies in study conduct including use of small sample size, inappropriate statistical methods and inadequate attention to the possibility that between-study differences in environmental factors may alter pain phenotypes through epigenetic mechanisms, have been identified as being significant.

Biocatalytic and semisynthetic optimization of the anti-invasive tobacco (1S,2E,4R,6R,7E,11E)-2,7,11-cembratriene-4,6-diol

Tobacco cembranoids were reported to inhibit tumorigenesis. Biocatalysis of (1S,2E,4R,6R,7E,11E)-2,7,11-cembratriene-4,6-diol (1) using the symbiotic Bacillus sp. NC5, Bacillus sp. NK8, and Bacillus sp. NK7, isolated from the Red Sea sponge Negombata magnifica, afforded two new and four known hydroxylated metabolites 3-8. The use of symbiotic marine bacteria as biocatalysts for bioactive natural product scaffolds is very rare. Cembranoid 1 carbamate analogs 9-11 were prepared by its reaction with corresponding isocyanates. Cembranoid 1 and its bioconversion and carabamate products show anti-invasive activity against the human highly metastatic prostate PC-3M cancer cell line at 10-50 nM doses in Matrigel assay.

Physiological changes in the pallidum in a progressive model of Parkinson's disease: Are oscillations enough?

Neurophysiological changes in the basal ganglia thalamo-cortical circuit associated with the development of parkinsonian motor signs remain poorly understood. Theoretical models have ranged from those emphasizing changes in mean discharge rate to increased oscillatory activity within the beta range. The present study characterized neuronal activity within and across the internal and external segments of the globus pallidus as a function of motor severity using a staged, progressively severe 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine model of Parkinsonism in three rhesus monkeys. An increase in coherence between neuronal pairs across the external and internal globus pallidus was present in multiple frequency bands in the parkinsonian state; both the peak frequency of oscillatory coherence and the variability were reduced in the parkinsonian state. The incidence of 8-20Hz oscillatory activity in the internal globus pallidus increased with the progression of the disease when pooling the data across the three animals; however it did not correlate with motor severity when assessed individually and increased progressively in only one of three animals. No systematic relationship between mean discharge rates or the incidence or structure of bursting activity and motor severity was observed. These data suggest that exaggerated coupling across pallidal segments contribute to the development of the parkinsonian state by inducing an exaggerated level of synchrony and loss of focusing within the basal ganglia. These data further point to the lack of a defined relationship between rate changes, the mere presence of oscillatory activity in the beta range and bursting activity in the basal ganglia to the motor signs of Parkinson's disease.

Quasi-Chemical Theory with Cluster Sampling from Ab Initio Molecular Dynamics: Fluoride (F-) Anion Hydration

Accurate predictions of the hydration free energy for anions typically has been more challenging than that for cations. Hydrogen bond donation to the anion in hydrated clusters such as F(H₂O) _n ^- can lead to delicate structures. Consequently, the energy landscape contains many local minima, even for small clusters, and these minima present a challenge for computational optimization. Utilization of cluster experimental results for the free energies of gas-phase clusters shows that even though anharmonic effects are interesting they need not be of troublesome magnitudes for careful applications of quasi-chemical theory to ion hydration. Energy-optimized cluster structures for anions can leave the central ion highly exposed, and application of implicit solvation models to these structures can incur more serious errors than those for metal cations. Utilizing cluster structures sampled from ab initio molecular dynamics simulations substantially fixes those issues.

Early detection of hand movements from electroencephalograms for stroke therapy applications

Movement-assist devices such as neuromuscular stimulation systems can be used to generate movements in people with chronic hand paralysis due to stroke. If detectable, motor planning activity in the cortex could be used in real time to trigger a movement-assist device and restore a person's ability to perform many of the activities of daily living. Additionally, re-coupling motor planning in the cortex with assisted movement generation in the periphery may provide an even greater benefit-strengthening relevant synaptic connections over time to promote natural motor recovery. This study examined the potential for using electroencephalograms (EEGs) as a means of rapidly detecting the intent to open the hand during movement planning in individuals with moderate chronic hand paralysis following a subcortical ischemic stroke. On average, attempts to open the hand could be detected from EEGs approximately 100-500 ms prior to the first signs of movement onset. This earlier detection would minimize device activation delays and allow for tighter coupling between initial formation of the motor plan in the cortex and augmentation of that plan in the periphery by a movement-assist device. This tight temporal coupling may be important or even essential for strengthening synaptic connections and enhancing natural motor recovery.

Comparison of single-ion molecular dynamics in common solvents

Laying a basis for molecularly specific theory for the mobilities of ions in solutions of practical interest, we report a broad survey of velocity autocorrelation functions (VACFs) of Li⁺ and PF₆^- ions in water, ethylene carbonate, propylene carbonate, and acetonitrile solutions. We extract the memory function, γ(t), which characterizes the random forces governing the mobilities of ions. We provide comparisons controlling for the effects of electrolyte concentration and ion-pairing, van der Waals attractive interactions, and solvent molecular characteristics. For the heavier ion (PF₆^-), velocity relaxations are all similar: negative tail relaxations for the VACF and a clear second relaxation for γt, observed previously also for other molecular ions and with n-pentanol as the solvent. For the light Li⁺ ion, short time-scale oscillatory behavior masks simple, longer time-scale relaxation of γt. But the corresponding analysis of the solventberg Li⁺H₂O₄ does conform to the standard picture set by all the PF₆^- results.

Redox-Active Heteroatom-Functionalized Polyacetylenes

The discovery of metallic conductivity in polyacetylene [-HC=CH-]_n upon doping represents a landmark achievement. However, the insolubility of polyacetylene and a dearth of methods for its chemical modification have limited its widespread use. Here, we employ a ring-opening metathesis polymerization (ROMP) protocol to prepare functionalized polyacetylenes (fPAs) bearing: (1) electron-deficient boryl (-BR₂ ) and phosphoryl (-P(O)R₂ ) side chains; (2) electron-donating amino (-NR₂ ) groups, and (3) ring-fused 1,2,3-triazolium units via strain-promoted Click chemistry. These functional groups render most of the fPAs soluble and can lead to intense light absorption across the visible to near-IR region. Also, the presence of redox-active boryl and amino groups leads to opposing near-IR optical responses upon (electro)chemical reduction or oxidation. Some of the resulting fPAs show greatly enhanced air stability when compared to known polyacetylenes. Lastly, these fPAs can be cross-linked to yield network materials with the full retention of optical properties.

The molecular basis of platelet biogenesis, activation, aggregation and implications in neurological disorders

Platelets are anucleated blood constituents, vital for hemostasis and involved in the pathophysiology of several cardiovascular, neurovascular diseases as well as inflammatory processes and metastasis. Over the past few years, the molecular processes that regulate the function of platelets in hemostasis and thrombosis have emerged revealing platelets to be perhaps more complex than may have been expected. The most understood part of platelets is to respond to a blood vessel injury by altering shape, secreting granule contents, and aggregating. These responses, while advantageous for hemostasis, can become detrimental when they root ischemia or infarction. Only a few transcription and signaling factors involved in platelet biogenesis have been identified till date. Platelets encompass an astonishingly complete array of organelles and storage granules including mitochondria, lysosomes, alpha granules, dense granules, a dense tubular system (analogous to the endoplasmic reticulum of nucleated cells); a highly invaginated plasma membrane system known as the open canalicular system (OCS) and large fields of glycogen. Platelets as a model cells to study neurological disorders have been recommended by several researchers since several counterparts exist between platelets and the brain, which make them interesting for studying the neurobiology of various neurological disorders. This review has been compiled with an aim to integrate the latest research on platelet biogenesis, activation and aggregation focusing on the molecular pathways that power and regulate these processes. The dysregulation of important molecular players affecting fluctuating platelet biology and thereby resulting in neurovascular diseases has also been discussed.

Bromodomain and extraterminal (BET) protein inhibitor, apabetalone, reduces ACE2 expression and attenuates SARS-CoV-2 infection in vitro

Background/Introduction

SARS-CoV-2 causes life threatening COVID-19 complications including acute coronary syndrome, venous thromboembolism, hyperinflammation and damage in multiple tissues. The SARS-CoV-2 “spike protein” binds cell surface receptors including angiotensin-converting enzyme 2 (ACE2) for entry into host cells to initiate infection. Host cell dipeptidyl peptidase-4 (DPP4 / CD26) is implicated as a cofactor in uptake. Recent evidence indicates expression of factors involved in SARS-CoV-2 uptake into host cells is regulated by BET proteins, epigenetic readers modulating gene expression. Apabetalone, the most clinically advanced BET inhibitor (BETi), is in phase 3 trials for cardiovascular disease (CVD) (a,b). In cultured human cardiomyocytes, apabetalone suppressed infection with SARS-CoV-2 and prevented dysfunction of cardiac organoids induced by the cytokine-storm that arises in patients with severe symptoms (c). However, anti-viral properties of apabetalone in other cell types are not known.

Purpose

To examine effects of apabetalone on SARS-CoV-2 infection in cell culture via downregulated expression of cell surface receptors involved in viral entry. Cell systems used mimic initial sites of infection in the lung as well as cell types contributing to complications in late stages of infection.

Methods

Gene expression was measured by real-time PCR, protein levels by immunoblot or flow cytometry, and binding of recombinant SARS-CoV-2 spike protein by flow cytometry. Infection with SARS-CoV-2 was determined in a BSL3 facility. Infectivity was quantified by determining levels of viral spike protein amongst total cells via imaging on an Operetta CLS.

Results

In Calu-3, a human bronchial epithelial cell line, apabetalone dose-dependently downregulated ACE2 gene expression (up to 98%), reduced ACE2 protein levels (up to 84%) and diminished binding of SARS-CoV-2 spike protein (up to 77%, p<0.001 for all parameters). Further, apabetalone abolished infection of Calu-3 cells with live SARS-CoV-2, which was comparable to other antiviral agents. Apabetalone-driven ACE2 downregulation was also observed in extrapulmonary cell types including HepG2, Huh-7 or primary hepatocytes (up to 90%, p<0.001 for all cell types), and Vero E6, a monkey kidney epithelial cell line (up to 38%, p<0.05). DPP4/CD26, a potential cofactor for SARS-CoV-2 uptake, was also downregulated by apabetalone in Calu-3 cells (mRNA ∼65% and protein ∼40%, p<0.001), which may be synergistic with ACE2 reductions to impede SARS-CoV-2 infection.

Conclusions

Apabetalone, an investigational drug for CVD, reduced cell surface receptors (ACE2 and DPP4) involved in SARS-CoV-2 uptake into host cells and dramatically attenuated SARS-CoV-2 infection/propagation in vitro. Our results suggest apabetalone can mitigate SARS-CoV-2 replication in multiple organs, which together with an established safety profile supports clinical evaluation of apabetalone to treat

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): COVID-19 Rapid Response Grant from the College of Medicine at the University of Nebraska Medical Center (to DE and SPMR), and by University of Nebraska Medical Center start-up funds (to DE).

Frustrated Lewis pair adducts of alkynyl-capped tetrelenes

The frustrated Lewis pair (FLP) adducts PB{ECl2} (PB = iPr2P(C6H4)BCy2; Cy = cyclohexyl; E = Si, Ge) were used to access a bis(alkynyl)-functionalized silylene and a germylene; the goal behind preparing these species was to obtain new unsaturated main group polymers [E(CCSiMe3)2]n upon heating. While the silylene adduct PB{Si(CCSiMe3)2} was stable up to 150 °C, the heavier element congener PB{Ge(CCSiMe3)2} underwent a complicated rearrangement process accompanied by Cy-group migration and Ge(II)-alkyne coordination. Density functional theory computations were performed to understand the mechanistic pathway for the unusual rearrangement of PB{Ge(CCSiMe3)2}.

Towards the photodeposition of SixGey-type materials via oligomers of cyclogermapentenes and cyclosilapentenes

This article provides an alternative pathway towards cyclosilapentenes (e.g., SiH2-iPr and SpiroSi) involving the use of Rieke magnesium to activate the requisite dienes for synthesis. Subsequent metal-mediated dehydrocoupling of cyclosilapentene SiH2-iPr and mixtures with another cyclogermapentene gives oligomers with backbone Si-Si (number average molecular weight, Mn = 1.0 kDa) and Si-Ge (Mn = 1.4 kDa) linkages, respectively. UV-irradiation (248 nm) of the abovementioned oligotetrelenes and the molecular spirosilane SpiroSi were examined in solution; while evidence for SixGey-type materials was noted through Raman and EDX spectroscopy, the presence of substantial amorphous carbon as a contaminant was also observed. (TD)-DFT computational studies on the spirosilane SpiroSi provide some insight into the lack of efficient SixGey photodeposition noted in this study.

Shapes of Nonsymmetric Capillary Bridges

Here we study the shapes of droplets captured between chemically distinct parallel plates. This work is a preliminary step toward characterizing the influence of second-phase bridging between biomolecular surfaces on their solution contacts, i.e., capillary attraction or repulsion. We obtain a simple, variable-separated quadrature formula for the bridge shape. The technical complication of double-ended boundary conditions on the shapes of nonsymmetric bridges is addressed by studying waists in the bridge shape, i.e., points where the bridge silhouette has zero derivative. Waists are generally expected with symmetric bridges, but waist points can serve to characterize shape segments in general cases. We study how waist possibilities depend on the physical input to these problems, noting that these formulas change with the sign of the inside-outside pressure difference of the bridge. These results permit a variety of different interesting shapes, and the development below is accompanied by several examples.

Knock-down of calcitonin receptor expression induces apoptosis and growth arrest of prostate cancer cells

Calcitonin (CT) and its receptor (CTR) are expressed only in basal epithelium of benign prostate and in whole epithelium of malignant prostates. Also, CT and CTR mRNA levels in prostate cancers increase with an increase in tumor grade. We tested the role of the CT/CTR autocrine axis on the tumorigenicity of prostate cancer cells. We enforced the expression of CTR in CT-positive/CTR-deficient PC-3 cells. In contrast, we knocked down CTR expression in CT/CTR-positive PC-3M cells. The effect of CTR modulation on the oncogenicity was evaluated by the rate of cell proliferation, invasion, colony formation and in vivo growth in nude mice. Up-regulation of CTR in PC-3 cells and its down-regulation in PC-3M cells significantly altered their tumorigenicity. Intratumorally administered CTR RNAi in preexisting PC-3M xenografts markedly attenuated their further growth. This treatment also led to a remarkable decrease in endothelial cell populations in the tumors and increase in apoptotic, PCNA-negative cell populations. Tumors receiving CTR RNAi treatment displayed markedly lower levels of urokinase-type plasminogen activator, phospho-Akt and survivin, suggesting CTR activates uPA-uPAR axis and PI-3-kinase-Akt-survivin pathway. These results suggest an important role for CT-CTR autocrine axis in the progression of localized prostate tumor to a metastatic phenotype, and offer a potential therapeutic option for invasive cancers.

Metabolic, skeletal, and cartilage effects of a high-fat diet and the therapeutic impact of MGL3196 are age- and sex-dependent in mice

Aged individuals with type 2 diabetes (T2D) may suffer from complications of common comorbid conditions like osteoporosis or osteoarthritis. MGL3196 (MGL) is a therapeutic thyroid hormone receptor beta (TRβ) agonist that has been shown to rescue non-alcoholic steatohepatitis by enhancing lipid metabolism. In a previous study, we demonstrated that MGL treatment protected against high-fat diet (HFD)-induced adiposity but increased HFD-induced trabecular bone loss in male mice. In this study, we explored the impact of MGL treatment on adiposity, bone, and cartilage in aged-21-month-old C57BL/6 J mice after a 12-week HFD regimen. Our results show that MGL reduced body weight as well as adverse effects caused by HFD adiposity, in male mice only. Aged HFD-fed male mice experienced cortical bone loss, in contrast to the trabecular bone loss observed in adult male mice. Notably, MGL treatment further exacerbated the cortical bone loss. Mechanical testing of tibias from aged male mice by 3-point bending revealed a reduced maximum load and tibia stiffness with HFD and MGL treatment. Transcriptome analyses for cortical bone formation regulators unveiled a decreased expression of Wnt16 and increased expression of the Wnt inhibitor, Sost, in the bones of HFD-fed male mice. Additionally, measurements of articular cartilage indicated that MGL treatment reduced articular cartilage degradation in both sexes, which was attributed to aging and a HFD. Our findings suggest tailored therapies are necessary to address the adverse effects of a HFD on fat, bone, and cartilage metabolism, specifically considering factors such as age and sex.