CWHM-974 is a fluphenazine derivative with improved antifungal activity against Candida albicans due to reduced susceptibility to multidrug transporter-mediated resistance mechanisms

Multidrug resistance (MDR) transporters such as ATP-Binding Cassette (ABC) and Major Facilitator Superfamily proteins are important mediators of antifungal drug resistance, particularly with respect to azole class drugs. Consequently, identifying molecules that are not susceptible to this mechanism of resistance is an important goal for new antifungal drug discovery. As part of a project to optimize the antifungal activity of clinically used phenothiazines, we synthesized a fluphenazine derivative (CWHM-974) with 8-fold higher activity against Candida spp. compared to the fluphenazine and with activity against Candida spp. with reduced fluconazole susceptibility due to increased MDR transporters. Here, we show that the improved C. albicans activity is because fluphenazine induces its own resistance by triggering expression of Candida drug resistance (CDR) transporters while CWHM-974 induces expression but does not appear to be a substrate for the transporters or is insensitive to their effects through other mechanisms. We also found that fluphenazine and CWHM-974 are antagonistic with fluconazole in C. albicans but not in C. glabrata, despite inducing CDR1 expression to high levels. Overall, CWHM-974 is one of the few examples of a molecule in which relatively small structural modifications significantly reduced susceptibility to multidrug transporter-mediated resistance.

Combination of Antimalarial and CNS Drugs with Antineoplastic Agents in MCF-7 Breast and HT-29 Colon Cancer Cells: Biosafety Evaluation and Mechanism of Action

Drug combination and drug repurposing are two strategies that allow to find novel oncological therapies, in a faster and more economical process. In our previous studies, we developed a novel model of drug combination using antineoplastic and different repurposed drugs. We demonstrated the combinations of doxorubicin (DOX) + artesunate, DOX + chloroquine, paclitaxel (PTX) + fluoxetine, PTX + fluphenazine, and PTX + benztropine induce significant cytotoxicity in Michigan Cancer Foundation-7 (MCF-7) breast cancer cells. Furthermore, it was found that 5-FU + thioridazine and 5-fluorouracil (5-FU) + sertraline can synergistically induce a reduction in the viability of human colorectal adenocarcinoma cell line (HT-29). In this study, we aim to (1) evaluate the biosafety profile of these drug combinations for non-tumoral cells and (2) determine their mechanism of action in cancer cells. To do so, human fetal lung fibroblast cells (MRC-5) fibroblast cells were incubated for 48 h with all drugs, alone and in combination in concentrations of 0.25, 0.5, 1, 2, and 4 times their half-maximal inhibitory concentration (IC₅₀). Cell morphology and viability were evaluated. Next, we designed and constructed a cell microarray to perform immunohistochemistry studies for the evaluation of palmitoyl-protein thioesterase 1 (PPT1), Ki67, cleaved-poly (ADP-ribose) polymerase (cleaved-PARP), multidrug resistance-associated protein 2 (MRP2), P-glycoprotein (P-gp), and nuclear factor-kappa-B (NF-kB) p65 expression. We demonstrate that these combinations are cytotoxic for cancer cells and safe for non-tumoral cells at lower concentrations. Furthermore, it is also demonstrated that PPT1 may have an important role in the mechanism of action of these combinations, as demonstrated by their ability to decrease PPT1 expression. These results support the use of antimalarial and central nervous system (CNS) drugs in combination regimens with chemotherapeutic agents; nevertheless, additional studies are recommended to further explore their complete mechanisms of action.

Based on Principles and Insights of COVID-19 Epidemiology, Genome Sequencing, and Pathogenesis: Retrospective Analysis of Sinigrin and ProlixinRX (Fluphenazine) Provides Off-Label Drug Candidates

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative pathogen of pandemic coronavirus disease 2019 (COVID-19). So far, no approved therapy has been developed to halt the spread of the pathogen, and unfortunately, the strategies for developing a new therapy will require a long time and very extensive resources. Therefore, drug repurposing has emerged as an ideal strategy toward a smart, versatile, quick way to confine the lethal disease. In this endeavor, natural products have been an untapped source for new drugs. This review represents the confederated experience of multidisciplinary researchers of 99 articles using several databases: Google Scholar, Science Direct, MEDLINE, Web of Science, Scopus, and PubMed. To establish the hypothesis, a Bayesian perspective of a systematic review was used to outline evidence synthesis. Our docking documentation of 69 compounds and future research agenda assumptions were directed toward finding an effective and economic anti-COVID-19 treatment from natural products. Glucosinolate, flavones, and sulfated nitrogenous compounds demonstrate direct anti-SARS-CoV-2 activity through inhibition protease enzymes and may be considered potential candidates against coronavirus. These findings could be a starting point to initiate an integrative study that may encompass interested scientists and research institutes to test the hypothesis in vitro, in vivo, and in clinics after satisfying all ethical requirements.

Characterization hiPSC-derived neural progenitor cells and neurons to investigate the role of NOS1AP isoforms in human neuron dendritogenesis

Abnormal dendritic arbor development has been implicated in a number of neurodevelopmental disorders, such as autism and Rett syndrome, and the neuropsychiatric disorder schizophrenia. Postmortem brain samples from subjects with schizophrenia show elevated levels of NOS1AP in the dorsolateral prefrontal cortex, a region of the brain associated with cognitive function. We previously reported that the long isoform of NOS1AP (NOS1AP-L), but not the short isoform (NOS1AP-S), negatively regulates dendrite branching in rat hippocampal neurons. To investigate the role that NOS1AP isoforms play in human dendritic arbor development, we adapted methods to generate human neural progenitor cells and neurons using induced pluripotent stem cell (iPSC) technology. We found that increased protein levels of either NOS1AP-L or NOS1AP-S decrease dendrite branching in human neurons at the developmental time point when primary and secondary branching actively occurs. Next, we tested whether pharmacological agents can decrease the expression of NOS1AP isoforms. Treatment of human iPSC-derived neurons with d-serine, but not clozapine, haloperidol, fluphenazine, or GLYX-13, results in a reduction in endogenous NOS1AP-L, but not NOS1AP-S, protein expression; however, d-serine treatment does not reverse decreases in dendrite number mediated by overexpression of NOS1AP isoforms. In summary, we demonstrate how an in vitro model of human neuronal development can help in understanding the etiology of schizophrenia and can also be used as a platform to screen drugs for patients.

In vitro and in vivo identification of clinically approved drugs that modify ACE2 expression

The COVID-19 pandemic caused by SARS-CoV-2 has is a global health challenge. Angiotensin-converting enzyme 2 (ACE2) is the host receptor for SARS-CoV-2 entry. Recent studies have suggested that patients with hypertension and diabetes treated with ACE inhibitors (ACEIs) or angiotensin receptor blockers have a higher risk of COVID-19 infection as these drugs could upregulate ACE2, motivating the study of ACE2 modulation by drugs in current clinical use. Here, we mined published datasets to determine the effects of hundreds of clinically approved drugs on ACE2 expression. We find that ACEIs are enriched for ACE2-upregulating drugs, while antineoplastic agents are enriched for ACE2-downregulating drugs. Vorinostat and isotretinoin are the top ACE2 up/downregulators, respectively, in cell lines. Dexamethasone, a corticosteroid used in treating severe acute respiratory syndrome and COVID-19, significantly upregulates ACE2 both in vitro and in vivo. Further top ACE2 regulators in vivo or in primary cells include erlotinib and bleomycin in the lung and vancomycin, cisplatin, and probenecid in the kidney. Our study provides leads for future work studying ACE2 expression modulators.

Influence of phenothiazine molecules on the interactions between positively charged poly-l-lysine and negatively charged DPPC/DPPG membranes

Phenothiazines are very effective antipsychotic drugs, which also have anticancer and antimicrobial activities. Despite being used in human treatment, the molecular mechanism of the biological actions of these molecules is not yet understood in detail. The role of the interactions between phenothiazines and proteins or lipid membranes has been much discussed. Herein, fourier-transform infrared (FTIR) spectroscopic studies were used to investigate the effect of three phenothiazines: fluphenazine (FPh); chlorpromazine (ChP); and propionylpromazine (PP) on the structures of a positively charged poly-l-lysine (PLL) peptide, a negatively charged dipalmitoylphosphatidylcholine/dipalmitoylphosphatidylglycerol (DPPC/DPPG) membrane, and on the mutual interactions between electrostatically associated PLL molecules and DPPC/DPPG membranes. Phenothiazine-induced alterations in the secondary structure of PLL, the conformational state (trans/gauche) of the hydrocarbon lipid chains, and the hydration of the DPPC/DPPG membrane interface were studied on the basis of amide I' vibrations, antisymmetric and symmetric stretching vibrations of the CH₂ groups of the lipid hydrocarbon chains (ν_sCH₂), and stretching vibrations of the lipid C=O groups (νC = O), respectively. It was shown that in the presence of negatively charged DPPC/DPPG membranes, the phenothiazines were able to modify the secondary structure of charged PLL molecules. Additionally, the effect of PLL on the structure of DPPC/DPPG membranes was also altered by the presence of the phenothiazine molecules.

FLUPHENAZINE AND PERPHENAZINE IMPACT ON MELANOGENESIS AND ANTIOXIDANT ENZYMES ACTIVITY IN NORMAL HUMAN MELANOCYTES

Fluphenazine and perphenazine as a phenothiazine-class antipsychotic drugs are widely used to treat psychoses and schizophrenia, however their use is associated with significant side effects such as extrapyramidal symptoms as well as ocular and skin disorders. The aim of this study was to examine the effect of fluphenazine and perphenazine on cell viability, melanogenesis and antioxidant defense system in normal human melanocytes. It has been shown that both phenothiazines induce concentration-dependent loss in cell viability. The value of EC₅₀. was calculated to be 1.24 and 2.76 μM for fluphenazine and perphenazine, respectively. Fluphenazine in concentration of 1.0 μM and perphenazine in concentrations of 1.0 and 3.0 μM inhibied melanogenesis and decreased microphthalmia-associated transcription factor content. To study the effect of both analyzed drugs on antioxidant defense system in melanocytes, the level of hydrogen peroxide and the activities of antioxidant enzymes: superoxide dismutase, catalase and glutathione peroxidase were determined. Fluphenazine and perphenazine in higher analyzed concentrations caused depletion of melanocytes antioxidant status, what indicated the induction of oxidative stress. The observed changes in melanization process and antioxidant defense system in pigmented cells exposed to fluphenazine and perphenazine in vibo suggest a significant role of melanin and melanocytes in the mechanisms of undesirable side effects of these drugs in vivo, especially directed to pigmented tissues. Moreover, the presented differences in modulation of biochemical processes in melanocytes may be an explanation for various toxic activity of the analyzed phenothiazine derivatives in vivo.

Autophagy induction enhances TDP43 turnover and survival in neuronal ALS models

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) have distinct clinical features but a common pathology--cytoplasmic inclusions rich in transactive response element DNA-binding protein of 43 kDa (TDP43). Rare TDP43 mutations cause ALS or FTD, but abnormal TDP43 levels and localization may cause disease even if TDP43 lacks a mutation. Here we show that individual neurons vary in their ability to clear TDP43 and are exquisitely sensitive to TDP43 levels. To measure TDP43 clearance, we developed and validated a single-cell optical method that overcomes the confounding effects of aggregation and toxicity and discovered that pathogenic mutations shorten TDP43 half-life. New compounds that stimulate autophagy improved TDP43 clearance and localization and enhanced survival in primary murine neurons and in human stem cell-derived neurons and astrocytes harboring mutant TDP43. These findings indicate that the levels and localization of TDP43 critically determine neurotoxicity and show that autophagy induction mitigates neurodegeneration by acting directly on TDP43 clearance.

Fluphenazine reduces proteotoxicity in C. elegans and mammalian models of alpha-1-antitrypsin deficiency

The classical form of α1-antitrypsin deficiency (ATD) is associated with hepatic fibrosis and hepatocellular carcinoma. It is caused by the proteotoxic effect of a mutant secretory protein that aberrantly accumulates in the endoplasmic reticulum of liver cells. Recently we developed a model of this deficiency in C. Elegans and adapted it for high-content drug screening using an automated, image-based array scanning. Screening of the Library of Pharmacologically Active Compounds identified fluphenazine (Flu) among several other compounds as a drug which reduced intracellular accumulation of mutant α1-antitrypsin Z (ATZ). Because it is representative of the phenothiazine drug class that appears to have autophagy enhancer properties in addition to mood stabilizing activity, and can be relatively easily re-purposed, we further investigated its effects on mutant ATZ. The results indicate that Flu reverses the phenotypic effects of ATZ accumulation in the C. elegans model of ATD at doses which increase the number of autophagosomes in vivo. Furthermore, in nanomolar concentrations, Flu enhances the rate of intracellular degradation of ATZ and reduces the cellular ATZ load in mammalian cell line models. In the PiZ mouse model Flu reduces the accumulation of ATZ in the liver and mediates a decrease in hepatic fibrosis. These results show that Flu can reduce the proteotoxicity of ATZ accumulation in vivo and, because it has been used safely in humans, this drug can be moved rapidly into trials for liver disease due to ATD. The results also provide further validation for drug discovery using C. elegans models that can be adapted to high-content drug screening platforms and used together with mammalian cell line and animal models.

ABC transporters coupled with the elevated ergosterol contents contribute to the azole resistance and amphotericin B susceptibility

Most screening approaches produce compounds that target survival genes and are likely to generate resistance over time. Simply having more drugs does not address the potential emergence of resistance caused by target mutation, drug efflux pumps over-expression, and so on. There is a great need to explore new strategies to treat fungal infections caused by drug-resistant pathogens. In this study, we found that azole-resistant Candida albicans with CaCDR1 and CaCDR2 over-expression is hypersensitive against amphotericin B (AmB) by our high throughput synergy screening (HTSS). In contrast, Δcdr1 and Δcdr2 knockout strains were resistant to AmB. Moreover, clinical isolates with increased expression of CaCDR1 and CaCDR2 demonstrated susceptibility to AmB, which can also synergize with the efflux pumps inducer fluphenazine (FPZ). Finally, the increased drug susceptibility to AmB in azole-resistant C. albicans with drug efflux pumps over-expression was consistent with the elevated expression of CaERG11 and its associated ergosterols in clinical isolates. Our data implies that the level of ergosterol contents determines the susceptibility to azoles and AmB in C. albicans. Deep understanding of the above mechanisms would offer new hope to treat drug-resistant C. albicans.

Synthesis, pro-apoptotic activity and 2D-QSAR studies of new analogues of fluphenazine

A series of 10 novel analogues of fluphenazine (FPh) were synthesized. Influence of the synthesized analogues of FPh on frequency of apoptosis and necrosis in cultures of human lymphocytes genotoxically damaged in vitro with benzo[a]pyrene (B[a]P; 7,5 microM, 48 h) was compared with the effect of FPh. Activity of the tested compounds was expressed by ED50 (pro-apoptotic activity) and TD50 (pro-necrotic effect, cytotoxicity). It was noticed that compounds 3-9 and 12 exerted a pro-apoptotic effect markedly stronger than that of FPh. Additionally, compounds 3, 9 and 10 exhibited the weakest influence on frequency of necrotic lymphocyte in cultures. 2D-QSAR analysis was done in order to find quantitative relationship between structures of the tested analogues and their pro-apoptotic activity or pro-necrotic effect in B[a]P-damaged cell cultures. Several statistically significant QSAR models were generated. Information obtained from 2D-QSAR study will be used in further design of analogues of FPh more active in cancer chemoprevention.

[Copper intoxication decreases lifespan and induces neurologic alterations in Drosophila melanogaster]

Wilson disease is a hereditary disorder caused by mutations of the ATP7B gene, which leads to intoxication with copper as a result of an unbalance of copper homeostasis. The clinical manifestations resulting from this intoxication are related to the affectation of liver and the encephalon in most cases. Several animal models are currently available for the study of the malady. However, in such models no neurological symptoms are observed, which limits their use for the study of pathogenic effects of this disease on the central nervous system. The aim of the present study was to evaluate if copper feeding could induce a disease state in Drosophila melanogaster to model Wilson disease. The effect of the feeding of copper at the doses of 31 microM and 47 microM on the survival was initially evaluated. Next, behavioral experiments were conducted to determine whether the motor performance was altered by the 47 microM concentration. The results suggest that copper treatment decreases the viability of the flies. In addition, the decrease of viability was associated to an increase and decrease of spontaneous motor activity at early and late stages of the intoxication, respectively. Finally, the role of the dopaminergic neurotransmission system on the observed motor alterations was evaluated. The dopamine precursor L-dopa increased motor activity. In contrast, D2 receptor antagonist, Fluphenazine, was able to block both the increase and decrease of motor activity scores induced by copper. These results suggest that Drosophila melanogaster could be used as a model organism for the study of possible interventions with potential neuroprotective effects in Wilson disease.

Automated high-content live animal drug screening using C. elegans expressing the aggregation prone serpin α1-antitrypsin Z

The development of preclinical models amenable to live animal bioactive compound screening is an attractive approach to discovering effective pharmacological therapies for disorders caused by misfolded and aggregation-prone proteins. In general, however, live animal drug screening is labor and resource intensive, and has been hampered by the lack of robust assay designs and high throughput work-flows. Based on their small size, tissue transparency and ease of cultivation, the use of C. elegans should obviate many of the technical impediments associated with live animal drug screening. Moreover, their genetic tractability and accomplished record for providing insights into the molecular and cellular basis of human disease, should make C. elegans an ideal model system for in vivo drug discovery campaigns. The goal of this study was to determine whether C. elegans could be adapted to high-throughput and high-content drug screening strategies analogous to those developed for cell-based systems. Using transgenic animals expressing fluorescently-tagged proteins, we first developed a high-quality, high-throughput work-flow utilizing an automated fluorescence microscopy platform with integrated image acquisition and data analysis modules to qualitatively assess different biological processes including, growth, tissue development, cell viability and autophagy. We next adapted this technology to conduct a small molecule screen and identified compounds that altered the intracellular accumulation of the human aggregation prone mutant that causes liver disease in α1-antitrypsin deficiency. This study provides powerful validation for advancement in preclinical drug discovery campaigns by screening live C. elegans modeling α1-antitrypsin deficiency and other complex disease phenotypes on high-content imaging platforms.

The antipsychotic drug, fluphenazine, effectively reverses mechanical allodynia in rat models of neuropathic pain

RATIONALE

Fluphenazine is a potent antipsychotic drug used to treat schizophrenia and other psychotic symptoms. Its clinical benefit is mainly mediated by the antagonism of dopamine D2 receptors. We have recently discovered, however, that fluphenazine is also a potent sodium channel blocker, a property that may offer additional therapeutical indications, including analgesia.

OBJECTIVES

The present study sought to determine the analgesic effect of fluphenazine on neuropathic pain in animal models.

METHODS

The effect of fluphenazine on mechanical allodynia was assessed in three animal neuropathic pain models, including spinal nerve ligation, chronic constriction nerve injury (CCI), and sural-spared sciatic nerve injury models.

RESULTS

Systemic fluphenazine effectively attenuated mechanical allodynia in all three rat neuropathic pain models at doses (0.03-0.3 mg/kg) that approximate those used in rodent models of psychosis. In parallel with its in vivo antiallodynic effect, fluphenazine (3-30 microM) effectively suppressed the ectopic discharges in injured afferent fibers without affecting the propagation of action potentials evoked by electrical nerve stimulation in an ex vivo dorsal root ganglia (DRG)-nerve preparation excised from CCI rats. Furthermore, similar concentrations of fluphenazine significantly blocked sodium channels in DRG neurons.

CONCLUSIONS

The inhibitory action of fluphenazine on ectopic afferent discharges may be due to its ability to block voltage-gated sodium channels, and this may also provide a mechanistic basis for the drug's antiallodynic effect in animal models of neuropathic pain. In summary, our study demonstrates that the classic antipsychotic drug fluphenazine has antiallodynic properties in multiple rodent models of nerve injury-induced neuropathic pain.

Intracerebroventricular ethanol-induced conditioned place preferences are prevented by fluphenazine infusions into the nucleus accumbens of rats

The rewarding properties of centrally administered ethanol (EtOH) were examined using a conditioned place preference (CPP) test. Male rats subjected to bilateral intracerebroventricular (icv) infusions of EtOH (0-240 nmol) produced a dose-dependent preference for the drug-paired environment that was potentiated by concurrent intravenous (iv) administration of heroin (0.025 mg/kg). The role of mesolimbic dopamine (DA) pathways in the development of EtOH reward was then examined by challenging EtOH-treated rats with bilateral intra-accumbens shell applications of a DA receptor antagonist. Fluphenazine (10 or 50 microg/side), infused immediately prior to daily place conditioning trials, was found to reliably attenuate the development of CPPs produced by icv EtOH administration. When fluphenazine was administered into the nucleus accumbens shell prior to the final test trial only (i.e., in already conditioned rats), intra-accumbens shell DA receptor blockade was found to prevent the expression of CPPs produced by icv EtOH. In summary, rats form reliable learned preferences for EtOH-paired locations (CPPs) that are potentiated by iv heroin and whose acquisition and expression rely on intact DA functionality within the nucleus accumbens.

Involvement of Ca2+- and cyclic adenosine monophosphate-mediated signaling pathways in photodynamic injury of isolated crayfish neuron and satellite glial cells

To investigate the mechanisms of oxidative injury of neurons and glia, we studied the photodynamic effect on isolated stretch receptor that consists of only two sensory neurons enwrapped by satellite glial cells. Photodynamic therapy (PDT), a potent inducer of oxidative stress, is a prospective method for destruction of brain tumors. PDT induced functional inactivation and necrosis of neurons, necrosis, apoptosis, and proliferation of glial cells. The roles of calmodulin, calmodulin-dependent kinase II, phospholipase C, protein kinases A and C, and phosphodiesterase in these processes were studied by using their inhibitors: fluphenazine, KN-93, D-609, H89, staurosporine, and papaverine, respectively. PDT-induced firing abolishment was enhanced by H89 or papaverine, whereas staurosporine acted oppositely. Fluphenazine or KN-93 reduced necrosis of neurons and glial cells. H89 enhanced necrosis of neurons, whereas staurosporine enhanced necrosis of glial cells. Inhibition of protein kinases A and C enhanced PDT-induced glial apoptosis. Photodynamic gliosis was prevented by KN-93 or staurosporine. These data indicate possible involvement of calmodulin and calmodulin-dependent kinase II in photoinduced necrosis of neurons and glia. Protein kinase C could protect glial cells from necrosis and apoptosis and participate in photoinduced gliosis and loss of neuronal activity. Protein kinase A maintained neuronal firing and protected neurons from photoinduced necrosis and glial cells from apoptosis. Phosphodiesterase reduced necrosis of photosensitized neurons and glia. Thus, Ca(2+)- and cAMP-mediated signaling pathways were involved in photooxidative injury of neurons and glia. Their pharmacological modulation may differently change the efficacy of photodynamic injury of neurons and glial cells.

The central role of PDR1 in the foundation of yeast drug resistance

The widespread pleiotropic drug resistance (PDR) phenomenon is well described as the long term selection of genetic variants expressing constitutively high levels of membrane transporters involved in drug efflux. However, the transcriptional cascades leading to the PDR phenotype in wild-type cells are largely unknown, and the first steps of this phenomenon are poorly understood. We investigated the transcriptional mechanisms underlying the establishment of an efficient PDR response in budding yeast. We show that within a few minutes of drug sensing yeast elicits an effective PDR response, involving tens of PDR genes. This early PDR response (ePDR) is highly dependent on the Pdr1p transcription factor, which is also one of the major genetic determinants of long term PDR acquisition. The activity of Pdr1p in early drug response is not drug-specific, as two chemically unrelated drugs, benomyl and fluphenazine, elicit identical, Pdr1p-dependent, ePDR patterns. Our data also demonstrate that Pdr1p is an original stress response factor, the DNA binding properties of which do not depend on the presence of drugs. Thus, Pdr1p is a promoter-resident regulator involved in both basal expression and rapid drug-dependent induction of PDR genes.

The neuroleptic drug, fluphenazine, blocks neuronal voltage-gated sodium channels

Fluphenazine (Prolixin(R)) is a potent phenothiazine-based dopamine receptor antagonist, first introduced into clinical practice in the late 1950s as a novel antipsychotic. The drug emerged as a 'hit' during a routine ion channel screening assay, the present studies describe our electrophysiological examination of fluphenazine at tetrodotoxin-sensitive (TTX-S) and resistant (TTX-R) voltage-gated sodium channel variants expressed in three different cell populations. Constitutively expressed TTX-S conductances were studied in ND7/23 cells (a dorsal root ganglion-derived clonal cell line) and rat primary cerebrocortical neurons. Recombinant rat Na(V)1.8 currents were studied using ND7/23 cells as a host line for heterologous expression. Sodium currents were examined using standard whole-cell voltage-clamp electrophysiology. Current-voltage relationships for either ND7/23 cell or Na(V)1.8 currents revealed a prominent fluphenazine block of sodium channel activity. Steady-state inactivation curves were shifted by approximately 10 mV in the hyperpolarizing direction by fluphenazine (3 microM for ND7/23 currents and 10 microM for Na(V)1.8), suggesting that the drug stabilizes the inactivated channel state. Fluphenazine's apparent potency for blocking either ND7/23 or Na(V)1.8 sodium channels was increased by membrane depolarization, corresponding IC(50) values for the ND7/23 cell conductances were 18 microM and 960 nM at holding potentials of -120 mV and -50 mV, respectively. Frequency-dependent channel block was evident for each of the cell/channel variants, again suggesting a preferential binding to inactivated channel state(s). These experiments show fluphenazine to be capable of blocking neuronal sodium channels. Several unusual pharmacokinetic features of this drug suggest that sodium channel block may contribute to the overall clinical profile of this classical neuroleptic agent.

Dopamine Antagonist Alters Serum Cortisol and Prolactin Secretion in Lactating Holstein Cows

The role of dopamine in regulating glucocorticoid and prolactin secretion was investigated in lactating Holstein cows by characterizing serum cortisol and prolactin responses to fluphenazine, a dopamine receptor antagonist. Twelve anovulatory cows received an intravenous bolus injection of either saline (n = 6) or 0.3 mg of fluphenazine/kg of body weight (n = 6) in wk 2 postpartum. Blood samples were collected every 30 min for 4 h before and 4 h after saline or fluphenazine injection. Serum progesterone concentration was 0.13 +/- 0.1 ng/mL and did not differ between groups. No difference in serum cortisol concentrations was detected between groups before treatments. Fluphenazine increased serum cortisol concentrations within 30 min after fluphenazine administration (>30 ng/mL) and concentrations remained elevated throughout the sampling period. Cortisol remained unchanged in saline-treated cows (<10 ng/mL). Prolactin concentrations also increased after fluphenazine administration (103.1 +/- 3.1 ng/mL), but were unaffected by saline (18 +/- 3.1 ng/mL). Prolactin concentrations remained elevated throughout the sampling period in fluphenazine-treated cows. Our results indicated that a dopamine antagonist increased cortisol, suggesting that endogenous dopamine, at least in part, regulates cortisol and prolactin secretion. These effects are regulated through dopamine receptors in anovulatory lactating dairy cows during the early postpartum period.

A mutation in Tac1p, a transcription factor regulating CDR1 and CDR2, is coupled with loss of heterozygosity at chromosome 5 to mediate antifungal resistance in Candida albicans

TAC1, a Candida albicans transcription factor situated near the mating-type locus on chromosome 5, is necessary for the upregulation of the ABC-transporter genes CDR1 and CDR2, which mediate azole resistance. We showed previously the existence of both wild-type and hyperactive TAC1 alleles. Wild-type alleles mediate upregulation of CDR1 and CDR2 upon exposure to inducers such as fluphenazine, while hyperactive alleles result in constitutive high expression of CDR1 and CDR2. Here we recovered TAC1 alleles from two pairs of matched azole-susceptible (DSY294; FH1: heterozygous at mating-type locus) and azole-resistant isolates (DSY296; FH3: homozygous at mating-type locus). Two different TAC1 wild-type alleles were recovered from DSY294 (TAC1-3 and TAC1-4) while a single hyperactive allele (TAC1-5) was isolated from DSY296. A single amino acid (aa) difference between TAC1-4 and TAC1-5 (Asn977 to Asp or N977D) was observed in a region corresponding to the predicted activation domain of Tac1p. Two TAC1 alleles were recovered from FH1 (TAC1-6 and TAC1-7) and a single hyperactive allele (TAC1-7) was recovered from FH3. The N977D change was seen in TAC1-7 in addition to several other aa differences. The importance of N977D in conferring hyperactivity to TAC1 was confirmed by site-directed mutagenesis. Both hyperactive alleles TAC1-5 and TAC1-7 were codominant with wild-type alleles and conferred hyperactive phenotypes only when homozygous. The mechanisms by which hyperactive alleles become homozygous was addressed by comparative genome hybridization and single nucleotide polymorphism arrays and indicated that loss of TAC1 heterozygosity can occur by recombination between portions of chromosome 5 or by chromosome 5 duplication.

Calpain activation contributes to oxidative stress-induced pancreatic acinar cell injury

Oxygen radicals have been implicated as mediators in the pathogenesis of pancreatic acinar cell necrosis. However, the sequence of events between the oxidative insult and cell damage remains unclear. In the current study, we investigated whether the Ca(2+)-regulated cytosolic cysteine protease calpain is activated by oxidative stress and contributes to oxidant-induced acinar cell damage. Isolated rat pancreatic acinar cells were exposed to hydrogen peroxide (H(2)O(2))-generated oxidative stress in the presence or absence of the Ca(2+) chelator 1,2-bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid tetraacetoxymethyl ester (BAPTA-AM) and different calpain inhibitors including benzyloxycarbonyl-valyl-phenylalanine methyl ester. Calpain activation was studied by fluorescence spectrophotometry and immunoblotting. Cell injury was assessed by lactate dehydrogenase (LDH) release and characterization of the cellular ultrastructure including fluorescence-labeled actin filaments. Exposure of acinar cells to H(2)O(2) provoked a time- and dose-dependent increase in calpain proteolytic activity involving the ubiquitous isoforms mu- and m-calpain. The activation of calpain reflected the time course of developing cytotoxicity as demonstrated by increased LDH release. Inhibition of oxidant-induced calpain activity by BAPTA-AM and various calpain inhibitors provoked a decline in oxidant-induced cell injury. In particular, changes in the actin filament organization characterized by an increase in the basolateral actin and by a detachment of actin from the cell membrane in the region of membrane blebs were clearly reduced. In summary, our findings suggest that acinar cell damage through oxidative stress requires activation of calpain and that the actin cytoskeleton belongs to the cellular targets of the protease. The results support the hypothesis that calpain activation may play a role in the development of acute pancreatitis.

Second-generation antipsychotic drugs, olanzapine, quetiapine, and clozapine enhance neurite outgrowth in PC12 cells via PI3K/AKT, ERK, and pertussis toxin-sensitive pathways

Second-generation antipsychotic drugs, olanzapine, quetiapine, and clozapine, were found to enhance neurite outgrowth induced by nerve growth factor (NGF) in PC12 cells. These drugs increased the number of cells bearing neurites, the length of primary neurites, and the size of the cell body of NGF-differentiated PC12 cells. In addition, the drugs induced sprouting of neurite-like processes in PC12 cells in the absence of NGF. Olanzapine, quetiapine, and clozapine enhanced the phosphorylation of Akt and ERK in combination with NGF, and specific inhibitors of these pathways attenuated these effects. Pretreatment of cells overnight with pertussis toxin had no effect on NGF-induced differentiation but significantly decreased the effects of the antipsychotic drugs on neurite outgrowth, suggesting that Gi/Go-coupled receptors are involved in the response to drug. A better understanding of the mechanisms underlying the effects of the second-generation drugs might suggest new therapeutic targets for enhancement of neurite outgrowth.

Calmodulin-myosin light chain kinase inhibition changes fibroblast-populated collagen lattice contraction, cell migration, focal adhesion formation, and wound contraction

Wound healing requires fibroblast migration, synthesis of new extracellular matrix, and organization of that matrix, all of which depend upon myosin ATPase activation and subsequent cytoplasmic actin-myosin contraction. Myosin ATPase activity is optimized by phosphorylation of myosin light chain at serine 19. Several different signaling pathways can perform that phosphorylation, the focus here is calcium saturated calmodulin dependent -myosin light chain kinase (CaM-MLCK). It is proposed that CaM-MLCK phosphorylation of myosin light chain and subsequent myosin ATPase activation affects granulation tissue fibroblast behavior and contributes to wound contraction. Myosin ATPase activity generates actin-myosin contraction within fibroblasts. Myosin ATPase activity is involved in ATP-induced cell contraction, the generation of focal adhesions, fibroblast migration, fibroblast populated collagen lattice (FPCL) contraction, and wound contraction. The MLCK inhibitors ML-9 and ML-7 inhibited ATP-induced cell contraction, fibroblast migration, FA formation, and FPCL contraction. The calmodulin inhibitors W7 and fluphenazine blocked rat open wound contraction. In addition, fluphenazine delayed re-epithelialization. These findings support the idea that fibroblast CaM-MLCK activity is essential for tissue repair. We speculate that inhibition of CaM-MLCK may reduce or prevent detrimental fibrotic contracture.

Repeated antipsychotic drug exposurein developing rats: Dopamine receptor effects

Antipsychotic drugs are often prescribed to juvenile psychiatric patients, though their cerebral effects during development are incompletely described. Accordingly, we studied the effects of repeated treatment with dissimilar antipsychotic drugs on dopamine (DA) receptors in juvenile vs. adult rats. Tissue levels of DA receptor types (D1, D2, D3, and D4) in forebrain regions of juvenile rats were quantified after 3 weeks of daily treatment with representative first- (fluphenazine) and second-generation (clozapine and olanzapine) antipsychotics, and compared with similarly treated adult rats examined in previous studies. Fluphenazine, clozapine, and olanzapine all decreased D1 receptors in dorsolateral frontal and medial prefrontal cortex (MPC) of juvenile, but not adult rats. Conversely, all three test agents increased D2 labeling in MPC of adult, but not young animals. Fluphenazine and olanzapine, but not clozapine, also increased D2 receptor levels in hippocampus, and D4 levels in nucleus accumbens (NAc) and caudate-putamen (CPu) in both juvenile and adult brain. D3 receptors were not altered by any treatment in any brain region at either age. Only some DA receptor adaptations to antipsychotic treatment are shared by developing and mature animals. Developmental differences in DA receptor responses may account for differences in clinical effects of antipsychotic drugs between young and adult psychiatric patients.