Association Between Open Payments-Reported Industry Transfers of Value and Prostaglandin Analog Prescribing in the US.

Importance: Reported transfers of value (TOV) from pharmaceutical companies have been associated with greater use of branded anti-vascular endothelial growth factor agents by ophthalmologists, but payment under the Medicare Part B buy-and-bill model includes a financial incentive to choose costlier agents, potentially confounding analyses of pharmaceutical TOV and prescribing patterns. How these reported TOV are associated with prescribing patterns for prescription eye drops, not subject to the incentives created by Part B payments, should be considered. Objective: To assess the association between prostaglandin analog (PGA) eye drop prescribing and reported nonresearch TOV by makers of branded PGAs to US vision care professionals. Design, Setting, and Participants: This retrospective cohort analysis used a 20% nationally representative sample of 2018 Medicare Part D claims and industry TOV reported to the Open Payments program. Optometrists and ophthalmologists who had more than 10 claims for PGA drops in the 20% sample were analyzed. Analysis took place from June 2021 to February 2022. Main Outcomes and Measures: Multivariable logistic regression assessing the association between membership in strata of reported TOV and branded PGA prescribing rate, controlling for prescriber demographic factors, local area practices, total PGA prescribing volume, and plan formularies involved. Results: A total of 20 612 ophthalmologists and 5426 optometrists (7449 [29%] female and 18 589 [71%] male) prescribed PGA eye drops. Of these, 9685 (37%) were reported to have received TOV from manufacturers of branded PGAs in 2018, totaling $5 060 346. The median (IQR) reported TOV was $65 ($24-$147). Multivariable logistic regression showed that the predicted probability of primarily prescribing branded PGAs among prescribers who reported receiving no TOV was 12.9% (95% CI, 12.4%-13.4%). This figure increased to 19.6% (95% CI, 18.8%-20.4%) among prescribers receiving TOV, a 50% increase. There was a dose-response association, such that the top 10% of TOV recipients had a 29.2% probability (95% CI, 26.4%-31.9%) of preferential branded use. Conclusions and Relevance: While the median reported TOV to a PGA prescriber was relatively low in this study, there was a positive association between amount of reported nonresearch TOV received from PGA makers and the frequency of branded PGA use. This shows that small reported TOV were associated with differences in prescribing. High rates of branded PGA prescribing may pose a cost burden to patients that affects adherence. Clinicians and policy makers should be aware of these associations.

Induction of DR5-Dependent Apoptosis by PGA2 through ATF4-CHOP Pathway.

Prostaglandin (PG) A2, a cyclopentenone PG, induced apoptosis in both HCT116 and HCT116 p53 -/- cells. Although PGA2-induced apoptosis in HCT116 cells was dependent on the p53-DR5 pathway, the mechanism underlying PGA2-induced apoptosis in HCT116 p53 -/- cells remains unknown. In this study, we observed that PGA2 caused an increase of mRNA expression of DR5 and protein expression even in HCT116 p53 -/- cells, accompanied by caspase-dependent apoptosis. Knockdown of DR5 expression by RNA interference inhibited PGA2-induced apoptosis in HCT116 p53 -/- cells. Parallel to the induction of apoptosis, PGA2 treatment upregulated expression of genes upstream of DR5 such as ATF4 and CHOP. Knockdown of CHOP prevented DR5-dependent cell death as well as the expression of DR5 protein. Furthermore, knockdown of ATF4 by RNA interference decreased both mRNA and protein levels of CHOP and DR5, thereby suppressing PGA2-induced cell death. Consistently, the DR5 promoter activity increased by PGA2 was not stimulated when the CHOP binding site in the DR5 promoter was mutated. These results collectively suggest that PGA2 may induce DR5-dependent apoptosis via the ATF4-CHOP pathway in HCT116 p53 null cells.

The risk of uveitis due to prostaglandin analogs in pediatric glaucoma.

PURPOSE: To examine the incidence of uveitis in children prescribed prostaglandin analogs (PGAs) for glaucoma. METHODS: In this dual-center cohort study, the medical records of consecutive patients <18 years old treated with a PGA between January 1, 2012, and December 31, 2018, were reviewed retrospectively. Patients with all forms of glaucoma, including those with a prior history of uveitis, were included. Patients who had been on a PGA prior to their first recorded visit were excluded. Patient charts were reviewed for new or recurrent uveitis during the first year of PGA therapy. RESULTS: A total of 103 children (147 eyes) were included, with a total PGA exposure of 1,352 child-months. Ninety-eight children (142 eyes) tolerated the PGA without an episode of uveitis. Five patients with a documented prior history of uveitis experienced a unilateral episode of uveitis. A review of their medical records identified prescribed or unscheduled decrease in topical steroids or immunosuppressive medication as the most likely cause of uveitis recurrence. CONCLUSIONS: This study provides further evidence that PGAs are unlikely to induce uveitis in children being treated for glaucoma and suggests that this may also be true in those with a history of uveitis. We are unable to evaluate whether PGAs make recurrence more likely or the tapering of steroids more difficult.

A comparison of country-level data from the VISIONARY study examining treatment outcomes with preservative-free tafluprost/timolol fixed-dose combination therapy.

OBJECTIVE: Analysis and comparison of country-level data from the VISIONARY study, examining treatment outcomes with the topical fixed-dose combination of preservative-free tafluprost (0.0015%) and timolol (0.5%) (PF tafluprost/timolol FC) in adults with open-angle glaucoma (OAG) and ocular hypertension (OHT) who were insufficiently treated with or unable to tolerate either beta-blocker or prostaglandin analogue (PGA) topical monotherapy. METHODS: A European, prospective, observational study was conducted in 11 countries. Adults with OAG/OHT were switched to the PF tafluprost/timolol FC from either PGA or beta-blocker topical monotherapy. Statistical analysis examined changes in mean standard deviation (SD) intraocular pressure (IOP) from baseline at Week 4, Week 12 and Month 6. Data were documented for each eye separately at baseline and during follow up visits, with the eye reported to have the higher IOP (mmHg), as measured using Goldmann applanation tonometry, being selected for analysis (study eye). Country-level subanalysis examined outcomes by prior monotherapy, diagnosis and timing of dosing for those countries recruiting ≥20 patients (Country-level Subanalysis Population). Two-sided paired t-test was used to assess significance regarding mean IOP reduction from baseline and a compound symmetry covariance model was used in cross-country comparisons regarding variation in IOP change from baseline. Treatment-related adverse events (AEs) were evaluated. RESULTS: Mean (SD) age among patients recruited to the VISIONARY study ranged between 63.9 (11.8) and 72.4 (10.6) years across all countries. The majority of participants (>50%) were female in each country. The Country-level Subanalysis Population included 551 eyes. Mean (SD) IOP was significantly reduced from baseline in each country at Week 4, Week 12 and Month 6 (p < .0001). Mean IOP reduction at Month 6 ranged from 5.0 mmHg (22.6%, Hungary) to 7.8 mmHg (31.8%, Latvia) and varied significantly between countries (p < .001). The greatest reductions were in Latvia and Russia, where baseline IOP was highest. Country-level IOP reductions were significant irrespective of prior monotherapy, diagnosis or dosing time (p < .0001). Most treatment-related AEs occurred in the UK (26 events, 73% mild). One serious AE was reported (Russia, status asthmaticus). Tolerability with PF tafluprost/timolol FC therapy was rated as good/very good by most patients (85.7-100%) in all countries. CONCLUSION: Subanalysis of VISIONARY study data revealed significant IOP reductions following a switch to the PF tafluprost/timolol FC from either PGA or beta-blocker topical monotherapy. Cross-country variation was likely due to baseline IOP differences. Within country, outcomes were consistent regardless of diagnosis, dosing or prior monotherapy. Treatment was generally well tolerated.

Switching to Preservative-Free Tafluprost/Timolol Fixed-Dose Combination in the Treatment of Open-Angle Glaucoma or Ocular Hypertension: Subanalysis of Data from the VISIONARY Study According to Baseline Monotherapy Treatment.

INTRODUCTION: The VISIONARY study demonstrated statistically significant intraocular pressure (IOP) reductions with the preservative-free fixed-dose combination of tafluprost 0.0015% and timolol 0.5% (PF tafluprost/timolol FC) in open-angle glaucoma (OAG) or ocular hypertension (OHT) patients, sub-optimally controlled with topical prostaglandin analogue (PGA) or beta-blocker monotherapy. Current subanalyses have examined these data according to the baseline monotherapy. METHODS: A European, prospective, observational study included adults (aged ≥ 18 years) with OAG or OHT, who were switched to the PF tafluprost/timolol FC from PGA or beta-blocker monotherapy. Treatment outcomes were reported according to prior monotherapy subgroup: beta-blocker, preserved latanoprost, PF-latanoprost, bimatoprost, tafluprost, and travoprost. Endpoints included the mean change from baseline regarding IOP, conjunctival hyperemia, and corneal fluorescein staining (CFS) at Week 4 and Week 12, and at Month 6. RESULTS: The subanalysis included 577 patients. All prior monotherapy subgroups demonstrated statistically significant IOP reductions from baseline at Week 4, that were maintained through Month 6 (p < 0.001). Mean (SD) IOP change at Month 6 was 6.6 (4.16), 6.3 (4.39), 5.6 (3.67), 4.9 (2.97), 4.6 (4.39), and 4.7  (3.64) mmHg for prior beta-blocker, preserved latanoprost, PF-latanoprost, tafluprost, bimatoprost, and travoprost subgroups, respectively. The largest IOP change was observed in the preserved latanoprost subgroup for each of the ≥ 20%, ≥ 25%, ≥ 30%, and ≥ 35% IOP reduction categories at Month 6, demonstrating respective reductions of 8.06, 9.20, 10.64, and 11.55 mmHg. CFS was significantly reduced at Month 6 in the prior bimatoprost subgroup (p = 0.0013). Conjunctival hyperemia severity was significantly reduced at each study visit for prior preserved latanoprost users (p < 0.001). CONCLUSION: PF tafluprost/timolol FC therapy provided statistically and clinically significant IOP reductions from Week 4 over the total 6-month period, in patients with OAG/OHT, regardless of the type of prior PGA or beta-blocker monotherapy used. Conjunctival hyperemia severity and CFS decreased significantly in prior bimatoprost and preserved latanoprost users, respectively. CLINICAL STUDY NUMBER: European Union electronic Register of Post-Authorization Studies (EU PAS) register number: EUPAS22204.

Effect of prostaglandin analogues on central corneal thickness in patients with glaucoma: A systematic review and meta-analysis with trial sequential analysis.

The objective of this meta-analysis was to evaluate the effect of prostaglandin analogues (PGA) on central corneal thickness (CCT) in patients with glaucoma. Key electronic databases were searched for randomized controlled trials (RCTs) involving the CCT effects of prostaglandin use for glaucoma. Primary outcome measures were the mean difference in the CCT measurement from baseline to the last available assessment. Intraocular pressure and other corneal changes were recorded as secondary. Efficacy estimates were measured by their weighted mean difference (WMD) with 95% confidence intervals (CI's) by using the random-effects model for primary and secondary outcomes Trial sequential analysis was used to determine if the current evidence was sufficient and conclusive. Eight RCTs met our inclusion criteria. A total of 879 patients were included. The overall effect showed that PGA's had a significant CCT lowering effect (WMD = -7.04, 95%CI: -10.07 to -4.00, P < 0.00001). We pooled results of 5 RCT's on Travoprost (WMD = -10.44, 95%CI: -16.80 to -4.08, P = 0.001), seven trials on Latanoprost (WMD = -4.73, 95% CI: -9.70 to 0.25, P = 0.06), and three trials on Bimatoprost (WMD = -11.88, 95%CI: -21.03 to -2.73, P = 0.01). The WMD across groups in >6 months of PGA use was -11.37 (95%CI: -17.17 to -5.58, P = 0.0001), and in <6 months of PGAs group was -8.35 (95% CI: -12.01 to -4.69, P < 0.00001), suggesting a longitudinal effect of PGAs on CCT. In conclusion, Bimatoprost and Travoprost caused a statistically significant reduction in the thickness of central cornea. Though only a few studies were included, the narrow confidence intervals and adequate sample size suggest that these findings are valid.

Relationships of dermatologic symptoms and quality of life in patients with psoriatic arthritis: analysis of two tofacitinib phase III studies.

OBJECTIVES: Evaluate relationships between changes in dermatologic assessments and quality of life (QoL) measures; quantify dermatologic symptom severity impacts on QoL in patients with psoriatic arthritis (PsA) treated with tofacitinib. METHODS: Data were from two phase III studies; patients received tofacitinib 5 or 10 mg twice daily (BID), adalimumab 40 mg every other week, or placebo advancing to tofacitinib 5 or 10 mg BID at Month 3. Repeated measures longitudinal models assessed relationships between dermatologic assessments (predictors) Itch Severity Item (ISI), Physician's Global Assessment of Psoriasis (PGA-PsO), and Patient's Global Joint and Skin Assessment-Visual Analog Scale-Psoriasis question (PGJS-VAS-PsO), and QoL measures (outcomes) Dermatology Life Quality Index (DLQI) and Short Form-36 Health Survey Version 2 (SF-36v2). Models included one predictor and one outcome. RESULTS: Direct, approximately linear relationships existed between predictors and outcomes. ISI/PGA-PsO/PGJS-VAS-PsO improvements from baseline of ≥3/≥2/≥40-mm VAS corresponded with clinically meaningful DLQI improvements; improvements from baseline of ≥4/≥3/≥40-mm VAS generally corresponded with clinically meaningful improvements across component scores and all SF-36v2 domains. CONCLUSIONS: Substantial links exist between dermatologic symptoms and QoL in patients with PsA, potentially informing patient-centered care and research. Rheumatologists should be aware of dermatologic manifestations and QoL impacts in patients with PsA. CLINICALTRIALS.GOV: NCT01877668; NCT01882439.

Prostaglandin A2 Interacts with Nurr1 and Ameliorates Behavioral Deficits in Parkinson's Disease Fly Model.

The orphan nuclear receptor Nurr1 is critical for the development, maintenance, and protection of midbrain dopaminergic neurons. Recently, we demonstrated that prostaglandins E1 (PGE1) and PGA1 directly bind to the ligand-binding domain (LBD) of Nurr1 and stimulate its transcriptional activation function. In this direction, here we report the transcriptional activation of Nurr1 by PGA2, a dehydrated metabolite of PGE2, through physical binding ably supported by NMR titration and crystal structure. The co-crystal structure of Nurr1-LBD bound to PGA2 revealed the covalent coupling of PGA2 with Nurr1-LBD through Cys566. PGA2 binding also induces a 21° shift of the activation function 2 (AF-2) helix H12 away from the protein core, similar to that observed in the Nurr1-LBD-PGA1 complex. We also show that PGA2 can rescue the locomotor deficits and neuronal degeneration in LRRK2 G2019S transgenic fly models.

Association of Topical Prostaglandin Analogue Use With Risk of Spontaneous Abortion.

Importance: Recent case reports suggest use of topical prostaglandin analogues (PGAs) might increase the risk of spontaneous abortions in pregnant people who take these drugs for intraocular pressure control. However, because these reports are derived mainly from voluntary adverse drug reaction databases, they might be prone to reporting bias. Objective: To examine the risk of spontaneous abortions among pregnant people who take topical PGAs. Design, Setting, and Participants: The PharMetrics Plus database (IQVIA) for health claims in the United States from 2006 to 2020 was used as the data source. The percentage of spontaneous abortions was quantified among patients aged 15 to 45 years who were pregnant and took a topical PGA medication during this period compared with a random sample of people in the database not taking a PGA agent. Main Outcomes and Measures: Diagnosis of a spontaneous abortion was ascertained through procedure codes or codes from the International Classification of Diseases, Ninth Revision, and International Statistical Classification of Diseases and Related Health Problems, Tenth Revision. Results: A total of 3881 people of reproductive age who were prescribed PGAs and 3881 control participants not taking PGAs were identified. Among the 3881 patients in the PGA cohort, 261 were pregnant and 26 had a spontaneous abortion code. Among the 26 individuals, 12 (4.6%) had a spontaneous abortion code within 90 days of the pregnancy code and had an overlapping prescription for a PGA. Among the 12 individuals, 5 (41.7%) were in the age category 40 to 45 years. In the control group, there were 801 pregnancies, 56 of which led to spontaneous abortions (7%), resulting in an increased risk of 2.4% (95% CI, -0.7% to 5.4%; P = .17). Conclusion and Relevance: The results of this case-series study suggest no association between use of PGAs and risk of spontaneous abortions. Given the nature of this study design and potential for unmeasured confounding factors, these results could be explored further in future epidemiologic studies that can better control for potential confounding variables and more accurately ascertain spontaneous abortions through perinatal databases.

Comparative effects of latanoprost and latanoprostene bunod on intraocular pressure and pupil size in ophthalmologically normal Beagle dogs.

OBJECTIVE: To compare effects of latanoprost, a topical prostaglandin analogue (PGA) commonly used to treat glaucoma and lens instability in dogs, and latanoprostene bunod, a novel PGA with a nitric oxide-donating moiety, on intraocular pressure (IOP) and pupil diameter (PD). ANIMALS STUDIED: Ten ophthalmologically normal Beagle dogs. PROCEDURES: Dogs were treated twice a day for 5 days in a randomly selected eye with either latanoprost or latanoprostene bunod. After a 6-week washout period, dogs were treated with the opposite drug. IOP and PD were measured at treatment times, at midday on days 1 and 5, and for 6 days post-treatment. RESULTS: Both drugs significantly decreased IOP and PD. At midday on day 5 of treatment, mean IOP in eyes treated with latanoprost was 4.5 mmHg lower than the fellow eye and 3.0 mmHg lower than the same eye at baseline, while mean IOP in eyes treated with latanoprostene bunod was 5.5 mmHg lower than the fellow eye and 3.6 mmHg lower than baseline. Mean PD was 0.94 mm in eyes treated with latanoprost and 0.76 mmHg in eyes treated with latanoprostene bunod. There was no significant difference between the two drugs for either parameter at that time point (p = .372 and .619, respectively, for IOP relative to control and to baseline; p = .076 for PD) or when analyzed longitudinally. Significant diurnal variation in PD was noted and may have implications for treatment of lens' instability. CONCLUSIONS: Latanoprost and latanoprostene bunod produce similar IOP reduction and miosis in normal canine eyes.

Treatment of Open-Angle Glaucoma and Ocular Hypertension with Preservative-Free Tafluprost/Timolol Fixed-Dose Combination Therapy: Results from the VISIONARY Study Population in Spain.

Purpose: Data are presented from ophthalmology clinics in Spain participating in the VISIONARY study, examining the effectiveness, tolerability, and safety of the preservative-free tafluprost (0.0015%) and timolol (0.5%) fixed-dose combination (PF tafluprost/timolol FC) in the treatment of OAG and OHT. Methods: An observational, multicenter prospective study examined treatment outcomes following a switch to PF tafluprost/timolol FC in adult OAG/OHT patients demonstrating insufficient response to beta-blocker or prostaglandin analog (PGA) monotherapy. Primary end point was mean change in intraocular pressure (IOP) from baseline at month 6. Changes in the severity of ocular signs and symptoms were also assessed. Results: Overall, 92 patients (51.1% female) were included. Mean (standard deviation) age was 68.3 (12.1) years. Mean IOP was reduced from 21.9 mmHg at baseline to 16.7 mmHg at month 6 (22.3% decrease; P < 0.0001). Significant IOP reductions were observed at weeks 4 and 12 (P < 0.0001). Baseline PGA and beta-blocker users demonstrated mean month 6 IOP reductions of 5.5 mmHg (23.5%; P < 0.001) and 3.5 mmHg (14.6%; P = 0.029), respectively. Severity of conjunctival hyperemia, dry eye, irritation, itching, foreign body sensation, and eye pain was significantly reduced. Three treatment-related adverse events were reported, all were nonserious and mild/moderate in severity. Conclusion: In real-world clinical practice, PF tafluprost/timolol FC treatment provided significant IOP reductions over 6 months and was well tolerated among OAG/OHT patients showing poor response to PGA or beta-blocker monotherapy. IOP-lowering efficacy and improvements in ocular signs and symptoms were evident from week 4 and maintained over the 6-month study period. Trial Registration: European Union electronic Register of Post-Authorisation Studies (EU PAS) register number EUPAS22204.

Topical prostaglandin analogue use and cystoid macular oedema following uneventful cataract surgery: a randomised control trial.

BACKGROUND/AIMS: The association between the development of cystoid macular oedema (CMO) following uneventful cataract surgery and prostaglandin analogue (PGA) therapy has not been fully determined. The study aim was to investigate whether discontinuation of PGA therapy following uneventful cataract surgery affected the incidence of postoperative CMO. METHODS: A prospective randomised controlled trial of 62 eyes of 62 participants with ocular hypertension (OH) or primary open angle glaucoma (POAG) treated with PGAs prior to cataract surgery. Participants were randomised to continue with PGA therapy after cataract surgery (CPGA) (n=31) or to discontinue PGA therapy (n=31). The primary outcome measure was the development of CMO at 1-month postoperatively, determined by a masked observer assessment of optical coherence tomography scans. The secondary outcome measure was change from baseline intraocular pressure (IOP). RESULTS: The incidence of CMO was identical in both groups at 12.9% (4 of 31 eyes) at the 1-month postoperative visit (OR 1.000; 95% CI 0.227 to 4.415). At 1-month postoperatively, the IOP was significantly lower in the CPGA group compared with baseline IOP. CONCLUSION: Continuation of PGA therapy following uneventful cataract surgery in eyes with normal macular morphology did not increase the incidence of CMO. Continuation of PGA therapy significantly reduced IOP at 1-month postoperatively suggesting that, when indicated, it might be beneficial to continue PGA therapy in patients with POAG or OH after uneventful cataract surgery in the absence of other risk factors for developing CMO.

Short-term efficacy of latanoprostene bunod for the treatment of open-angle glaucoma and ocular hypertension: a systematic literature review and a network meta-analysis.

BACKGROUND/AIMS: To assess the comparative efficacy of latanoprostene bunod (LBN), a novel prostaglandin analogue (PGA), to other medications for open-angle glaucoma and ocular hypertension on lowering intraocular pressure (IOP). METHODS: A systematic literature review adapted from the Li et al (Ophthalmology, 2016) study was conducted. Medline, Embase and PubMed were searched for randomised controlled trials published between 1 January 2014 and 19 March 2020. Studies had to report IOP reduction after 3 months for at least two different treatments among placebo, PGAs (bimatoprost 0.01%, bimatoprost 0.03%, latanoprost, LBN, tafluprost, unoprostone) or apraclonidine, betaxolol, brimonidine, brinzolamide, carteolol, dorzolamide, levobunolol, timolol, travoprost. A Bayesian network meta-analysis was performed to provide the relative effect in terms of mean difference (95% credible interval) of IOP reduction and ranking probabilities. Surface under the cumulative ranking curve (SUCRA) was generated. RESULTS: A total of 106 trials were included with data for 18 523 participants. LBN was significantly more effective than unoprostone (-3.45 (-4.77 to -2.12)). Although relative effect was not significative, compared with other PGAs, LBN numerically outperformed latanoprost (-0.70 (-1.83 to 0.43)) and tafluoprost (-0.41 (-1.87 to 1.07)), was similar to bimatoprost 0.01% (-0.02(-1.59 to 1.55)) and was slightly disadvantaged by bimatoprost 0.03% (-0.17 (-1.42 to 1.07)). LBN was significantly more efficient than the beta-blockers apraclonidine, betaxolol, brimonidine, brinzolamide, carteolol, dorzolamide and timolol. According to SUCRA, LBN was ranked second after bimatoprost 0.03%, followed by bimatoprost 0.01%. CONCLUSION: LBN was significantly more effective than the PGA unoprostone and most of the beta-blockers. Compared with the most widely used PGAs, LBN numerically outperformed latanoprost and travoprost and was similar to bimatoprost 0.01%.

Prostaglandin A2 induces apoptosis in three cell lines derived from the fall armyworm, Spodoptera frugiperda.

Animals maintain homeostasis of cell numbers, constantly creating new cells and eliminating others. Programmed cell death, apoptosis, is a mechanism of cell elimination and it acts in many aspects of animal biology. Drawing on the biomedical background, several signals launch the apoptosis mechanisms, including prostaglandins (PGs). Based on this information, we posed the hypothesis that PGs similarly induce apoptosis in insect cell lines. We used three Spodoptera frugiperda cell lines, including two newly established, BCIRL-SfNS-0518B-YL derived from the central nervous system and BCIRL-Sf4FB-0614-SGS derived from fat body, and the commercially available Sf9 cells. Using a kinetic apoptosis kit, we found treating SfNS cells for 18 h with 15 or 20 µM PGA2 led to decreases in cell numbers, coupled with increased numbers of apoptotic and dead cells. Similar exposures to 10 µM PGA2 (24 h) led to substantial increases in apoptotic cells, confirmed by a terminal deoxynucleotidyl transferase dUTP nick end labeling assay on a flow cytometer. The influence of PGA2 treatments increased with dosage, as we recorded about 20% apoptosis at 24 h post-PGA2 treatments (10 µM) and about 34% apoptosis at 24 h post-30 µM treatments. PGA2 treatments led to 10- to 30-fold increases in messenger RNAs (mRNAs) encoding apoptosis-specific caspases-1, -2, -3, and -5 at 12 h and 40- to 60-fold increases in mRNAs encoding caspases-1 and -2, 10-fold increases for caspases-3 and -5 at 24 h. These findings strongly support our hypothesis that PGs induce apoptosis in an insect cell line and confirm an additional PG action in insect biology.

Identification of potential serum metabolic biomarkers for patient with keratoconus using untargeted metabolomics approach.

This study aimed to investigate the metabolite differences between patients with keratoconus and control subjects and identify potential serum biomarkers for keratoconus using a non-targeted metabolomics approach. Venous blood samples were obtained from patients with keratoconus (n = 20) as well as from age-, gender- and race-matched control subjects (n = 20). Metabolites extracted from serum were separated and analyzed by liquid chromatography/quadrupole time-of-flight mass spectrometer. Processing of raw data and analysis of the data files was performed using Agilent Mass Hunter Qualitative software. The identified metabolites were subjected to a principal component and hierarchical cluster analysis. Appropriate statistical tests were used to analyze the metabolomic profiling data. Together, the analysis revealed that the dehydroepiandrosterone sulfate from the steroidal hormone synthesis pathway was significantly upregulated in patients with keratoconus (p < 0.05). Also, a combination of eicosanoids from the arachidonic acid pathway, mainly prostaglandin F2α, prostaglandin A2, 16,16-dimethyl prostaglandin E2, and 5-hydroxyeicosatetraenoic acid were collectively up-regulated as a group in keratoconus patients (p < 0.05). On the other hand, glycerophospholipid PS(17:2(9Z,12Z)/20:4(5Z,8Z,11Z,14Z)) was found to be significantly upregulated in the metabolomics profiles of control subjects (p < 0.05). The differently regulated metabolites provide insights into the pathophysiology of keratoconus and could potentially be used as biomarkers for keratoconus to aid in screening for individuals at risk hence, enabling early diagnosis and timely monitoring of disease.

A-family anti-inflammatory cyclopentenone prostaglandins: A novel class of non-statin inhibitors of HMG-CoA reductase.

Disruption of the intracellular lipid balance leading to cholesterol accumulation is one of the features of cells that participate in the development of atherosclerotic lesions. Evidence form our laboratory indicates that anti-inflammatory cyclopentenone prostaglandins (cyPGs) of A- and J-family deviate lipid metabolism from the synthesis of cholesterol and cholesteryl esters to the synthesis of phospholipids in foam-cell macrophages. cyPGs possessing an α,ß-unsaturated cyclopentane ring are highly electrophilic substances able to promptly react with reactive cysteines of intracellular molecules through Michael addition. On the other hand, HMG-CoA reductase (HMGCR), the enzyme responsible for the rate-limiting step in cholesterol biosynthesis, presents critically reactive cysteines at the entry of catalytic domain, particularly Cys561, that could be target of cyPG inhibition. In the present study, we showed that cyPGs (but not other non-α,ß-unsaturated PGs) physically interact with HMGCR, in a dithiothreitol- and ß-mercaptoethanol-sensitive way, and block the activity of the catalytic subunit of the enzyme (IC50 for PGA2 = 0.17 µM). PGA2 inhibits HMGCR activity in cultured rat and human macrophages/macrophage-foam cells and leads to enhanced expression of HMGCR protein, as observed with statins. In cell culture models, PGA2 effectively inhibits the reductase at non-toxic doses (e.g., 1 µM) that block cell proliferation thus suggesting that part of the well-known antiproliferative effect of PGA2 may be due to its ability of blocking HMGCR activity, as cells cannot proliferate without a robust cholesterogenesis. Therefore, besides the powerfully anti-inflammatory and antiproliferative effects, the anticholesterogenic effects of PGA2 should be exploited in atherosclerosis therapeutics.

Prostaglandin A1 Decreases the Phosphorylation of Tau by Activating Protein Phosphatase 2A via a Michael Addition Mechanism at Cysteine 377.

Prostaglandin (PG) A1 is a metabolic product of cyclooxygenase 2 (COX-2) that is potentially involved in regulating the development and progression of Alzheimer's disease (AD). PGA1 is a cyclopentenone (cy) PG characterized by the presence of a chemically reactive α,ß-unsaturated carbonyl. PGA1 is potentially involved in the regulation of multiple biological processes via Michael addition; however, the specific roles of PGA1 in AD remain unclear. TauP301S transgenic (Tg) mice were used as in vivo AD models, and neuroblastoma (N) 2a cells were used as an in vitro neuronal model. The PGA1-binding proteins were identified by HPLC-MS-MS after intracerebroventricular injection (i.c.v) of PGA1. Western blotting was used to determine tau phosphorylation in PGA1-treated Tg mice in the absence or in the presence of okadaic acid (OA), an inhibitor of protein phosphatase (PP) 2A. A combination of pull-down assay, immunoprecipitation, western blotting, and HPLC-MS-MS was used to determine that the PP2A scaffold subunit A alpha (PPP2R1A) is activated by the direct binding of PGA1 to cysteine 377. The effect of inhibiting tau hyperphosphorylation was tested in the Morris maze to determine the inhibitory effects of PGA1 on cognitive decline in tauP301S Tg mice. Incubation with N2a cells, pull-down assay, and mass spectrometry (MS) analysis revealed and indicated that PGA1 binds to more than 1000 proteins; some of these proteins are associated with AD and especially with tauopathies. Moreover, short-term administration of PGA1 in tauP301S Tg mice significantly decreased tau phosphorylation at Thr181, Ser202, and Ser404 in a dose-dependent manner. This effect was caused by the activation of PPP2R1A in tauP301S Tg mice. Importantly, PGA1 can form a Michael adduct with cysteine 377 of PPP2R1A, which is critical for the enzymatic activity of PP2A. Long-term treatment of tauP301S Tg mice with PGA1 activated PP2A and significantly reduced tau phosphorylation resulting in improvements in cognitive decline in tauP301S Tg mice. Our data provided new insight into the mechanisms of the ameliorating effects of PGA1 on cognitive decline in tauP301S Tg mice by activating PP2A via a mechanism involving the formation of a Michael adduct with cysteine 377 of PPP2R1A.

Development of Rifapentine-Loaded PLGA-Based Nanoparticles: In vitro Characterisation and in vivo Study in Mice.

BACKGROUND: Tuberculosis (TB) is a leading cause of death amongst infectious diseases. The poor response to antitubercular agents necessitates the long-term use of high drug doses, resulting in low patient compliance, which is the main reason for chemotherapy failure and contributes to the development of multidrug-resistant TB. Patient non-compliance has been a major obstacle in the successful management of TB. The aim of this work was to develop and characterise rifapentine (RPT)-loaded PLGA-based nanoparticles (NPs) for reducing dosing frequency. METHODS: RPT-loaded PLGA and PLGA-PEG NPs were prepared using premix membrane homogenisation combined with solvent evaporation method. The resulting NPs were characterised in terms of physicochemical characteristics, toxicity, cellular uptake and antitubercular activity. NPs were further evaluated for pharmacokinetic and biodistribution studies in mice. RESULTS: The resulting NPs showed suitable and safe physicochemical characteristics and could be taken up by macrophages. RPT-loaded NPs were more effective against Mycobacterium tuberculosis than free RPT. In vivo studies revealed that NPs could improve pharmacokinetic parameters, particularly for RPT/PLGA-PEG NPs. Moreover, both formulations had no toxicity to the organs of mice and could reduce hepatotoxicity. CONCLUSION: The application of PLGA-based NPs as sustained-release delivery vehicles for RPT could prolong drug release, modify pharmacokinetics, increase antitubercular activity and diminish toxicity, thereby allowing low dosage and frequency.

PGE1 and PGA1 bind to Nurr1 and activate its transcriptional function.

The orphan nuclear receptor Nurr1 is critical for the development, maintenance and protection of midbrain dopaminergic (mDA) neurons. Here we show that prostaglandin E1 (PGE1) and its dehydrated metabolite, PGA1, directly interact with the ligand-binding domain (LBD) of Nurr1 and stimulate its transcriptional function. We also report the crystallographic structure of Nurr1-LBD bound to PGA1 at 2.05 Å resolution. PGA1 couples covalently to Nurr1-LBD by forming a Michael adduct with Cys566, and induces notable conformational changes, including a 21° shift of the activation function-2 helix (H12) away from the protein core. Furthermore, PGE1/PGA1 exhibit neuroprotective effects in a Nurr1-dependent manner, prominently enhance expression of Nurr1 target genes in mDA neurons and improve motor deficits in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-lesioned mouse models of Parkinson's disease. Based on these results, we propose that PGE1/PGA1 represent native ligands of Nurr1 and can exert neuroprotective effects on mDA neurons, via activation of Nurr1's transcriptional function.