Computational repurposing of therapeutic small molecules from cancer to pulmonary hypertension

Cancer therapies are being considered for treating rare noncancerous diseases like pulmonary hypertension (PH), but effective computational screening is lacking. Via transcriptomic differential dependency analyses leveraging parallels between cancer and PH, we mapped a landscape of cancer drug functions dependent upon rewiring of PH gene clusters. Bromodomain and extra-terminal motif (BET) protein inhibitors were predicted to rely upon several gene clusters inclusive of galectin-8 (LGALS8). Correspondingly, LGALS8 was found to mediate the BET inhibitor–dependent control of endothelial apoptosis, an essential role for PH in vivo. Separately, a piperlongumine analog’s actions were predicted to depend upon the iron-sulfur biogenesis gene ISCU. Correspondingly, the analog was found to inhibit ISCU glutathionylation, rescuing oxidative metabolism, decreasing endothelial apoptosis, and improving PH. Thus, we identified crucial drug-gene axes central to endothelial dysfunction and therapeutic priorities for PH. These results establish a wide-ranging, network dependency platform to redefine cancer drugs for use in noncancerous conditions.

Pharmacologically-induced mitotic synchrony in airway epithelial cells as a mechanism of action of anti-inflammatory drugs

BACKGROUND

Mitotic synchrony is the synchronous progression of a population of cells through the cell cycle and is characteristic of non-diseased airway epithelial cells. However, we previously showed that asthmatic airway epithelial cells are characterized by mitotic asynchrony and are pro-inflammatory as a result. Glucocorticoids can induce mitotic synchrony that in turn suppresses the pro-inflammatory state of diseased cells, suggesting a novel anti-inflammatory mechanism of action. Herein, we benchmarked traditional glucocorticoids against the ability of a new clinical-stage dissociative steroidal drug, VBP15, for mitotic resynchronization and associated anti-inflammatory activity in asthmatic airway epithelial cells.

METHODS

Primary airway epithelial cells differentiated at air-liquid interface were exposed to VBP15, dexamethasone or vehicle following in vitro mechanical injury. Basolateral cytokine secretions (TGF-β1, IL-6, IL-10, IL-13, and IL-1β) were analyzed at different time points using cytometric bead assays and mitosis was examined by flow cytometry.

RESULTS

VBP15 improved mitotic synchrony of proliferating asthmatic cells in air-liquid interface cultures compared to vehicle-exposed cultures. VBP15 also significantly reduced the basolateral secretion of pro-inflammatory (i.e. IL-1β) and pro-fibrogenic cytokines (i.e. TGF-β1) in air-liquid interface-differentiated asthmatic epithelial cultures following mechanical injury.

CONCLUSION

VBP15 improves mitotic asynchrony and injury-induced pro-inflammatory and fibrogenic responses in asthmatic airway epithelial cultures with efficacy comparable to traditional glucocorticoids. As it is predicted to show superior side effect profiles compared to traditional glucocorticoids, VBP15 holds potential for treatment of asthma and other respiratory conditions.

HLA associations in schizophrenia: are we re-discovering the wheel?

Associations between human leukocyte antigen (HLA) polymorphisms on chromosome 6p and schizophrenia (SZ) risk have been evaluated for over five decades. Numerous case-control studies from the candidate gene era analyzed moderately sized samples and reported nominally significant associations with several loci in the HLA region (sample sizes, n = 100-400). The risk conferred by individual alleles was modest (odds ratios < 2.0). The basis for the associations could not be determined, though connections with known immune and auto-immune abnormalities in SZ were postulated. Interest in the HLA associations has re-emerged following several recent genome-wide association studies (GWAS); which utilized 10- to 100-fold larger samples and also identified associations on the short arm of chromosome 6. Unlike the earlier candidate gene studies, the associations are statistically significant following correction for multiple comparisons. Like the earlier studies; they have modest effect sizes, raising questions about their utility in risk prediction or pathogenesis research. In this review, we summarize the GWAS and reflect on possible bases for the associations. Suggestions for future research are discussed. We favor, in particular; efforts to evaluate local population sub-structure as well as further evaluation of immune-related variables in future studies.

Human induced pluripotent stem cell-derived models to investigate human cytomegalovirus infection in neural cells

Human cytomegalovirus (HCMV) infection is one of the leading prenatal causes of congenital mental retardation and deformities world-wide. Access to cultured human neuronal lineages, necessary to understand the species specific pathogenic effects of HCMV, has been limited by difficulties in sustaining primary human neuronal cultures. Human induced pluripotent stem (iPS) cells now provide an opportunity for such research. We derived iPS cells from human adult fibroblasts and induced neural lineages to investigate their susceptibility to infection with HCMV strain Ad169. Analysis of iPS cells, iPS-derived neural stem cells (NSCs), neural progenitor cells (NPCs) and neurons suggests that (i) iPS cells are not permissive to HCMV infection, i.e., they do not permit a full viral replication cycle; (ii) Neural stem cells have impaired differentiation when infected by HCMV; (iii) NPCs are fully permissive for HCMV infection; altered expression of genes related to neural metabolism or neuronal differentiation is also observed; (iv) most iPS-derived neurons are not permissive to HCMV infection; and (v) infected neurons have impaired calcium influx in response to glutamate.

Evaluation of HLA polymorphisms in relation to schizophrenia risk and infectious exposure

BACKGROUND

Genome-wide association studies (GWAS) implicate single nucleotide polymorphisms (SNPs) on chromosome 6p21.3-22.1, the human leukocyte antigen (HLA) region, as common risk factors for schizophrenia (SZ). Other studies implicate viral and protozoan exposure. Our study tests chromosome 6p SNPs for effects on SZ risk with and without exposure.

METHOD

GWAS-significant SNPs and ancestry-informative marker SNPs were analyzed among African American patients with SZ (n = 604) and controls (n = 404). Exposure to herpes simplex virus, type 1 (HSV-1), cytomegalovirus (CMV), and Toxoplasma gondii (TOX) was assayed using specific antibody assays.

RESULTS

Five SNPs were nominally associated with SZ, adjusted for population admixture (P < .05, uncorrected for multiple comparisons). These SNPs were next analyzed in relation to infectious exposure. Multivariate analysis indicated significant association between rs3130297 genotype and HSV-1 exposure; the associated allele was different from the SZ risk allele.

CONCLUSIONS

We propose a model for the genesis of SZ incorporating genomic variation in the HLA region and neurotropic viral exposure for testing in additional, independent African American samples.

W::Neo: a novel dual-selection marker for high efficiency gene targeting in Drosophila

We have recently developed a so-called genomic engineering approach that allows for directed, efficient and versatile modifications of Drosophila genome by combining the homologous recombination (HR)-based gene targeting with site-specific DNA integration. In genomic engineering and several similar approaches, a “founder” knock-out line must be generated first through HR-based gene targeting, which can still be a potentially time and resource intensive process. To significantly improve the efficiency and success rate of HR-based gene targeting in Drosophila, we have generated a new dual-selection marker termed W::Neo, which is a direct fusion between proteins of eye color marker White (W) and neomycin resistance (Neo). In HR-based gene targeting experiments, mutants carrying W::Neo as the selection marker can be enriched as much as fifty times by taking advantage of the antibiotic selection in Drosophila larvae. We have successfully carried out three independent gene targeting experiments using the W::Neo to generate genomic engineering founder knock-out lines in Drosophila.

Cell division autoantigen 1 plays a profibrotic role by modulating downstream signalling of TGF-beta in a murine diabetic model of atherosclerosis

AIMS/HYPOTHESIS

Excess accumulation of vascular extracellular matrix (ECM) is an important pathological process in cardiovascular diseases including diabetes-associated atherosclerosis. We explored how a recently identified molecule, cell division autoantigen 1 (CDA1), influences the profibrotic TGF-beta pathway leading to vascular ECM accumulation.

METHODS

Expression levels of genes encoding for CDA1, TGF-beta and connective tissue growth factor (CTGF) were examined in aorta from Apoe(-/-) mice with or without diabetes. We used retroviral and adenoviral constructs to knockdown or overexpress Tspyl2, the gene encoding CDA1, in mouse vascular smooth muscle cells (VSMCs) with or without TGF-beta treatment in order to demonstrate the role of CDA1 in TGF-beta signalling.

RESULTS

In vivo studies indicated that the mRNA levels of CDA1-encoding gene Tspyl2 and protein levels of CDA1 were elevated in the aorta of diabetic Apoe(-/-) mice, accompanied by increased levels of Tgf-beta (also known as Tgfb1), Ctgf and ECM accumulation. In vitro studies in vascular cells showed that TGF-beta treatment rapidly increased CDA1 protein levels, which then amplified TGF-beta signalling leading to upregulation of ECM genes. Knockdown of CDA1-encoding gene Tspyl2 to reduce cellular CDA1 level markedly attenuated TGF-beta-stimulated MAD homologue 3 (drosophila; SMAD3) phosphorylation and transcriptional activities. CDA1 overproduction increased and Tspyl2 knockdown decreased expression of TGF-beta receptor type I, TbetarI (also known as Tgfbr1), but not TGF-beta receptor type II, TbetarII (also known as Tgfbr2), providing a mechanism for CDA1's action in modulating TGF-beta signalling. Knockdown of CDA1-encoding gene Tspyl2 also blocked the profibrotic effect of TGF-beta in VSMCs.

CONCLUSIONS/INTERPRETATION

CDA1 plays an important role in vascular ECM accumulation by amplifying TGF-beta signalling. This is critical for the profibrotic effect of TGF-beta in the vasculature. CDA1 is therefore a potential target for attenuating vascular ECM accumulation caused by enhanced TGF-beta action, as seen in diabetic atherosclerosis.

Cytochrome P450 and antioxidant activity in interleukin-6 knockout mice after induction of the acute-phase response

Hepatic cytochrome P450 (CYP) expression and antioxidant activity have been shown to decrease following endotoxin (lipopolysaccharide [LPS]) or proinflammatory cytokine administration. Using mice deficient in interleukin-6 (IL-6), the role of IL-6 in the regulation of hepatic CYP activity, glutathione (GSH) metabolism, and catalase (CAT) activity was analyzed after LPS administration. Administration of LPS produced comparable decreases in hepatic CYP3A activity in WT B6x129 (WT) mice and IL-6 knockout mice. No decrease was observed for CYP2D9 activity after LPS administration in either WT or IL-6 knockout mice. LPS administration significantly increased hepatic and renal CYP2E1 and CYP4A activity in WT mice, with no effect in IL-6 knockout mice. CYP2A12 activity increased in IL-6 knockout, mice with no change in WT mice after LPS administration. LPS administration had no significant effect on hepatic GSH reductase, GST peroxidase, GSH-S-transferase (GST), or total GSH in either WT or IL-6 knockout. However, hepatic CAT activity was significantly reduced in WT mice after LPS administration, with no effect in IL-6 knockout mice. These results support IL-6 as a critical mediator of the effects of LPS on specific hepatic and renal CYP activities and hepatic CAT activity.

Activities of conjugating and antioxidant enzymes following endotoxin exposure

Endotoxin exposure elicits various responses in mammals including the acute phase response that has been shown to cause changes in the activity of several forms of cytochrome P450s and other enzymes. Therefore, the hepatic conjugating enzyme, glutathione S-transferase (GST), and UDP-glucuronosyltransferase (UDPGT), the antioxidant enzymes, glutathione peroxidase (GSHPx), catalase, and superoxide dismutase (SOD), as well as lipid peroxidation were investigated following the administration of endotoxin to male Sprague-Dawley rats (8 mg/kg body weight). Rats were euthanized at various times following endotoxin administration and the livers removed and processed to assess various enzyme activities. Glutathione S-transferase, UDPGT, and GSHPx activity showed statistically significant decreases after 24 hours and remained lower than controls for the duration of the study. Decreases in total SOD and catalase activities were seen at 24, 48, and 72 hours following endotoxin administration; however, only catalase activity showed statistically significant differences between control and treated samples at those time points, and total SOD activity showed a statistically significant decrease at 24 hours. No statistically significant changes were seen in the level of lipid peroxidation in the liver microsomes from endotoxin-treated animals. Changes in the conjugative enzymes and the free-radical scavenging enzymes following endotoxin exposure may alter the host's metabolism and response to free radicals.

Effect of leptin on cytochrome P-450, conjugation, and antioxidant enzymes in the ob/ob mouse

Leptin is a hormone that is secreted by adipocytes and regulates body weight through its effect on satiety and energy metabolism. The ob/ob mouse is deficient in this protein and is characterized by obesity and other metabolic disorders. This study investigated the alterations of several hepatic cytochrome P-450 (CYP), conjugation, and antioxidant enzymes in lean and ob/ob mice and the role leptin plays in the modulation of these enzymes. Lean and ob/ob male mice were injected with leptin (100 microg) or PBS for 15 days. Liver microsomes from ob/ob mice, when compared with lean controls, displayed significantly reduced chlorzoxazone 6-hydroxylation activity (27%); however, 7alpha- and 16alpha- testosterone hydroxylation and pentoxyresorufin O-dealkylation activities were significantly higher (47%, 22%, and 39%, respectively). Leptin administration corrected alterations seen with all P-450 activities. Dealkylation of ethoxyresorufin and omega-hydroxylation of lauric acid activities from ob/ob and lean mice were not statistically different; however, leptin exposure significantly increased ethoxyresorufin activity in lean mice (14%) and decreased the activity in ob/ob mice (36%). UDP-glucuronosyl-transferase and glutathione S-transferase activities were not altered. The antioxidant enzymes, catalase (11%) and glutathione peroxidase (26%), as well as glutathione reductase (17%), were lower in the ob/ob mice and leptin treatment corrected these alterations. The results of this study demonstrate alterations in constitutive expression of CYP2B, CYP2E, CYP2A, catalase, glutathione peroxidase, and glutathione reductase in ob/ob mice that were restored to lean control values following leptin treatment. Additionally, CYP3A activity was increased following leptin treatment in ob/ob mice. The mechanism for the observed alterations may be due to direct leptin effects or via indirect alterations in insulin, corticosterone, and/or growth hormone.

Disseminated echovirus infection after allogeneic bone marrow transplantation

Disseminated enteric human cytopathogenic orphan (echo) virus infection after allogeneic bone marrow transplantation has been reported once previously: a patient developed a fatal infection with the virus being isolated from brain, lung and heart. We report a second case of disseminated echovirus infection in which virus was isolated from the stomach and liver. On this occasion the infection was associated with the development of biopsy-proven acute graft-versus-host disease of the skin, stomach, colon and liver. The infection resolved without sequelae.

Acute pancreatitis complicating a bone marrow harvest

A patient developing acute pancreatitis with pseudocyst formation after an uncomplicated bone marrow harvest is reported. The diagnosis was confirmed by elevated serum amylase and lipase, and by CT scan. We suggest that the pancreatitis may have been precipitated by spasm of the sphincter of Oddi secondary to opiates administered as premedication and for pain relief.

Parathyroid hormone-related protein in hypercalcaemia associated with haematological malignancy

The incidence of hypercalcaemia and its association with humoral mechanisms involving parathyroid hormone-related protein (PTHrP), parathyroid hormone (PTH), or 1.25(OH)2 vitamin D were assessed in a prospective study of patients admitted to a clinical haematology unit. Hypercalcaemia was detected in 18/165 patients, and was due to primary hyperparathyroidism in 3/17 patients in whom results of humoral mediator assessments were obtained. In the other patients, hypercalcaemia was associated in nine instances with myeloma, in five with B-cell non-Hodgkin's lymphoma (NHL), and in one with myeloid neoplasia. No evidence was obtained of a humoral mechanism involving 1.25(OH)2 vitamin D, but elevated circulating levels of PTHrP, comparable with those in humoral hypercalcaemia of malignancy, were present in 2/4 patients with NHL, and in 3/9 with myeloma. The relationship between presence or absence of elevated circulating PTHrP, and presence or absence of hypercalcaemia during the course of treatment, indicated PTHrP was involved in the production of hypercalcaemia. Such an association raises the possibility that PTHrP released by neoplastic cells in these disorders acts in a paracrine manner to produce local bone resorption, and when produced in greater amounts causes elevated circulating levels which make an additional humorally-mediated contribution to the development of hypercalcaemia.

The effect of high and low dosages of paraoxon in beta-naphthoflavone-treated rats

Aliesterases (carboxylesterases) are serine esterases that can serve a protective role for the target acetylcholinesterase (AChE) during organophosphorus insecticide intoxication because the former esterases are alternate phosphorylation sites. The levels of aliesterase activity in liver and plasma and AChE activity in brain regions were investigated after the intravenous administration of paraoxon (P = O) into female rats. The rats were pretreated intraperitoneally with beta-napthoflavone (BNF), which decreases hepatic aliesterase activity following a 3 day in vivo treatment, and/or tri-o-tolyl phosphate (TOTP) to inhibit aliesterases. The liver aliesterases were inhibited less by P = O in BNF-treated rats than in control rats, which suggests that either BNF exposure may have resulted in aliesterases that are less sensitive to P = O inhibition or BNF may have altered P = O's availability. The BNF treatment did not seem to alter the degree of inhibition of the brain AChE activity following the low dosage of paraoxon (0.04 mg/kg). However, the brain AChE activity in the P = O/TOTP/BNF-treated rats was lower than that in the P = O/TOTP-treated rats, suggesting that BNF also caused changes in systems affecting the disposition of P = O in addition to the changes in the hepatic aliesterases. At the high dosage of paraoxon (0.12 mg/kg), the AChE and aliesterase activities showed a pattern similar to that of the low dosage. This suggests that the aliesterases, as altered by BNF exposure, even when nearly completely inhibited, did not alter the response of the target enzyme, AChE, and, therefore, the magnitude of the toxic response.

An investigation of activities and paraoxon sensitivities of hepatic aliesterases in beta-naphthoflavone-treated rats

Aliesterases (carboxylesterases, EC 3.1.1.1) are serine esterases which may protect acetylcholinesterase during organophosphorus insecticide intoxication by providing alternative phosphorylation sites. Levels of hepatic aliesterase activity were investigated after the intraperitoneal administration of beta-naphthoflavone (BNF) to female rats using nine 4-nitrophenyl esters as substrates (including straight and branched chain aliphatic and aromatic esters) and 1-naphthyl acetate. In addition, the in vitro sensitivities of aliesterases to inhibition by paraoxon, the active metabolite of the common insecticide parathion, were studied. Hepatic aliesterases from BNF-treated rats displayed lower activities than those from the controls with all substrates except 4-nitrophenyl phenylbutyrate and isovalerate. The aliesterases from BNF-treated rats were more sensitive to paraoxon inhibition with 4-nitrophenyl phenylbutyrate, valerate, and butyrate. Esterases hydrolyzing 4-nitrophenyl butyrate, valerate, and branched chain esters were most sensitive to paraoxon inhibition while those hydrolyzing 4-nitrophenyl hexanoate and aromatic esters were least sensitive. The results suggested that BNF-induced changes in hepatic aliesterases could alter responses to organophosphates.

An effective age-unrestricted m-AMSA-based second-line regimen for poor prognosis acute myeloid leukaemia

The efficacy and toxicity of a regimen consisting of amsacrine (m-AMSA), cytarabine, and thioguanine for remission-induction therapy in poor prognosis categories of acute myeloid leukaemia (AML) were determined in a single arm study of 46 patients. The study group consisted of 17 patients with disease refractory to daunorubicin plus cytarabine-based induction regimens, 22 patients with disease which had relapsed during daunorubicin plus cytarabine maintenance therapy, or following completion of this maintenance programme after receiving > or = 500 mg daunorubicin/m2, and 7 previously untreated patients where cardiac disease contraindicated anthracycline therapy. Complete remission (CR) was attained in 46%, and probability of survival was comparable to published results for first-line treatment with daunorubicin plus cytarabine regimens. There was no statistically significant difference in CR rate or probability of survival between these three categories of poor prognosis AML, and cardiotoxic complications were uncommon despite extensive anthracycline exposure in the majority. In the 43% of patients who were 60-76 years of age, there was no statistically significant difference in CR rate or probability of survival relative to patients < 60 years. This observation fails to support the view that less myelotoxic regimens with lesser efficacy should be the basic approach to treatment of AML in patients > or = 60 years of age.