Discovery and Optimization of N-Heteroaryl Indazole LRRK2 Inhibitors.

Inhibition of leucine-rich repeat kinase 2 is a genetically supported mechanism for the treatment of Parkinson's disease. We previously disclosed the discovery of an indazole series lead that demonstrated both safety and translational risks. The safety risks were hypothesized to be of unknown origin, so structural diversity in subsequent chemical matter was prioritized. The translational risks were identified due to a low brain Kpu,u in nonhuman primate studies, which raised concern over the use of an established peripheral biomarker as a surrogate for central target engagement. Given these challenges, the team sought to leverage structure- and property-based drug design and expanded efflux transporter profiling to identify structurally distinct leads with enhanced CNS drug-likeness. Herein, we describe the discovery of a "reinvented" indazole series with improved physicochemical properties and efflux transporter profiles while maintaining excellent potency and off-target kinase selectivity, which resulted in advanced lead, compound 23.

A Polymer Thick Film on an Organic Substrate Grid Electrode and an Open-Source Recording System for UHF MRI: An Imaging Study.

Electrocorticography (ECoG) is a critical tool in preclinical neuroscience research for studying global network activity. However, integrating ECoG with functional magnetic resonance imaging (fMRI) has posed challenges, due to metal electrode interference with imaging quality and heating around the metallic electrodes. Here, we introduce recent advancements in ECoG grid development that utilize a polymer-thick film on an organic substrate (PTFOS). PTFOS offers notable advantages over traditional ECoG grids. Firstly, it significantly reduces imaging artifacts, ensuring minimal interference with MR image quality when overlaying brain tissue with PTFOS grids. Secondly, during a 30-min fMRI acquisition, the temperature increase associated with PTFOS grids is remarkably low, measuring only 0.4 °C. These findings suggest that utilizing ECoG with PTFOS grids has the potential to enhance the safety and efficacy of neurosurgical procedures. By providing clearer imaging results and mitigating risk factors such as excessive heating during MRI scans, PTFOS-based ECoG grids represent a promising advancement in neurosurgical technology. Furthermore, we describe a cutting-edge open-source system designed for simultaneous electrophysiology and fMRI. This system stands out due to its exceptionally low input noise levels (<0.6 V peak-to-peak), robust electromagnetic compatibility (it is suitable for use in MRI environments up to 9.4 teslas), and the inclusion of user-programmable real-time signal-processing capabilities. The open-platform software is a key feature, enabling researchers to swiftly implement and customize real-time signal-processing algorithms to meet specific experimental needs. This innovative system has been successfully utilized in several rodent EEG/fMRI studies, particularly at magnetic field strengths of 4.7 and 9.4 teslas, focusing on the somatosensory system. These studies have allowed for detailed observation of neural activity and responses within this sensory system, providing insights that are critical for advancing our understanding of neurophysiological processes. The versatility and high performance of our system make it an invaluable tool for researchers aiming to integrate and analyze complex datasets from advanced imaging and electrophysiological recordings, ultimately enhancing the depth and scope of neuroscience research.

Update on Low-Renin Hypertension: Current Understanding and Future Direction.

Low-renin hypertension is common and affects 1 in 4 people with hypertension. Understanding the different causes and management of low-renin hypertension is becoming increasingly relevant as renin measurements are more widely ordered in clinical practice. Importantly, many people with low-renin hypertension do not fit traditional definitions of known causes, and the approach to management of these people is not unclear. This review provides an overview of our evolving understanding of the causes of low-renin hypertension, the expanding spectrums of pathophysiology, key differentiating characteristics, distinct management strategies, and highlights our knowledge gaps. It is important to distinguish the underlying pathophysiology of an individual with low-renin hypertension to individualize treatment.

Prevalence and Characteristics of Low-renin Hypertension in a Primary Care Population.

Introduction: Low-renin hypertension is an underrecognized subtype of hypertension with specific treatment options. This study aims to identify the prevalence in primary care and to compare patient characteristics to those with normal-renin hypertension and primary aldosteronism (PA). Methods: In a cohort study, patients with treatment-naïve hypertension were screened for PA with plasma aldosterone and direct renin concentrations. Patients with an elevated aldosterone-to-renin ratio [≥70 pmol/mU (≥2.5 ng/dL:mU/L)] underwent confirmatory testing. All screened patients were then classified as having (1) normal-renin hypertension, (2) low-renin hypertension (direct renin concentration <10mU/L (plasma renin activity ∼<1 ng/mL/hour) and not meeting the criteria for PA), or (3) confirmed PA. Results: Of the 261 patients, 69 (26.4%) had low-renin hypertension, 136 (51.9%) had normal renin hypertension, and 47 (18.0%) had PA. Patients with low-renin hypertension were older and more likely to be female compared to normal-renin hypertension (57.1 ± 12.8 years vs 51.8 ± 14.0 years, P < .05 and 68.1% vs 49.3%, P < .05, respectively) but similar to PA (53.5 ± 11.5 years and 55.3%). However, in an adjusted binomial logistic regression, there was no association between increasing age or sex and low-renin hypertension. The median aldosterone concentration was lower compared to patients with normal-renin hypertension and PA: 279 pmol/L (216-355) vs 320 pmol/L (231-472), P < .05 and 419 pmol/L (360-530), P < .001. Conclusion: At least a quarter of treatment-naïve hypertensive patients in primary care had a low direct renin concentration but did not meet the criteria for PA. Patient characteristics were similar, aside from a lower aldosterone concentration compared to patients with normal-renin hypertension and PA. Further research is needed to understand the underlying pathophysiology of low-renin hypertension and the optimal first-line treatment.

A Randomized trial assessing Efficacy and safety of Mineralocorticoid receptor Antagonist therapy compared to Standard antihypertensive Therapy in hypErtension with low Renin (REMASTER): rationale and study design.

Low-renin hypertension affects 1 in 4 people with hypertension, but the optimal management of this condition is not known. We hypothesize that a large proportion of people with low-renin hypertension is mediated by excess mineralocorticoid receptor (MR) activation and that targeted treatment with an MR antagonist (MRA) will be beneficial. This randomized, single-blinded, titration-to-effect aims to investigate whether targeted treatment in low-renin hypertension with MRA is better compared to standard antihypertensives in terms of blood pressure control and end-organ protection. Adults with hypertension, who are treatment naïve or are receiving up to two antihypertensive agents and have a low direct renin concentration <10 mU/L will be included. Participants with severe hypertension, a secondary cause of hypertension, pregnant, breastfeeding, with moderate-severe cardiovascular and chronic kidney disease, or on medications that confound interpretation of the plasma direct renin or aldosterone concentrations will be excluded. Eligible participants will be randomized 1:1 to either MRA therapy (spironolactone) or standard anti-hypertensive therapy (perindopril+/- amlodipine) for 48 weeks. Anti-hypertensives will be up-titrated every 12 weeks until target blood pressure is achieved. The primary objective will be to determine the total defined daily dose of antihypertensives required to achieve the target blood pressure and change in mean clinic systolic blood pressure at week 48. Current hypertension guidelines do not have specific recommendations for the choice of anti-hypertensive medications for people with low-renin hypertension. The results of this trial could guide future hypertension guidelines.

Challenges in Diagnosing and Managing the Spectrum of Primary Aldosteronism.

Primary aldosteronism, characterized by the dysregulated production of aldosterone from 1 or both adrenal glands, is the most common endocrine cause of hypertension. It confers a high risk of cardiovascular, renal, and metabolic complications that can be ameliorated with targeted medical therapy or surgery. Diagnosis can be achieved with a positive screening test (elevated aldosterone to renin ratio) followed by confirmatory testing (saline, captopril, fludrocortisone, or oral salt challenges) and subtyping (adrenal imaging and adrenal vein sampling). However, the diagnostic pathway may be complicated by interfering medications, intraindividual variations, and concurrent autonomous cortisol secretion. Furthermore, once diagnosed, careful follow-up is needed to ensure that treatment targets are reached and adverse effects, or even recurrence, are promptly addressed. These challenges will be illustrated in a series of case studies drawn from our endocrine hypertension clinic. We will offer guidance on strategies to facilitate an accurate and timely diagnosis of primary aldosteronism together with a discussion of treatment targets which should be achieved for optimal patient outcomes.

Prevalence of primary aldosteronism in acute stroke or transient ischemic attack: a systematic review and meta-analysis.

Background and purpose: Primary aldosteronism (PA) is the most common endocrine cause of secondary hypertension with a prevalence of 14% in patients with newly diagnosed hypertension. Patients with PA experience a higher rate of cardiovascular events including stroke when compared to those with blood pressure matched essential hypertension. This systematic review and meta-analysis summarize current evidence on the prevalence of PA in patients with acute stroke or transient ischemic attack (TIA). Methods: Two reviewers independently reviewed the literature for observational studies on the prevalence of PA in patients with acute stroke or TIA. MEDLINE and Embase were searched for studies up to December 13, 2023. Results: Three single center studies conducted in Japan, Singapore and China were found to meet the inclusion criteria. The reported prevalence of PA in two cohort studies of adults with stroke or TIA were 3.1% and 4.0% and a third cross-sectional study in adults under 45 years old revealed a prevalence rate of 12.9%. Following a meta-analysis, the pooled prevalence of PA in adults with stroke or TIA is 5.8% [95% CI 1.6%-12.3%]. Conclusions: A considerable proportion of patients with stroke or TIA may have PA as the underlying cause of their hypertension. Given the increased risk of stroke associated with PA, clinicians should consider screening for PA in hypertensive patients with stroke or TIA. Further research is needed to evaluate the effect of timing and interfering medications on test results, which will inform an evidence-based approach to testing for PA following TIA or stroke. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022328644.

Subtype Identification of Surgically Curable Primary Aldosteronism During Treatment With Mineralocorticoid Receptor Blockade.

BACKGROUND: Current guidelines and consensus documents recommend withdrawal of mineralocorticoid receptor antagonists (MRAs) before primary aldosteronism (PA) subtyping by adrenal vein sampling (AVS), but this practice can cause severe hypokalemia and uncontrolled high blood pressure. Our aim was to investigate if unilateral PA can be identified by AVS during MRA treatment. METHODS: We compared the rate of unilateral PA identification between patients with and without MRA treatment in large data sets of patients submitted to AVS while off renin-angiotensin system blockers and ß-blockers. In sensitivity analyses, the between-group differences of lateralization index values after propensity score matching and the rate of unilateral PA identification in subgroups with undetectable (≤2 mUI/L), suppressed (<8.2 mUI/L), and unsuppressed (≥8.2 mUI/L) direct renin concentration levels were also evaluated. RESULTS: Plasma aldosterone concentration, direct renin concentration, and blood pressure values were similar in non-MRA-treated (n=779) and MRA-treated (n=61) patients with PA, but the latter required more antihypertensive agents (P=0.001) and showed a higher rate of adrenal nodules (82% versus 67%; P=0.022) and adrenalectomy (72% versus 54%; P=0.01). However, they exhibited no significant differences in commonly used AVS indices and the area under the receiving operating characteristic curve of lateralization index, both under unstimulated conditions and postcosyntropin. Several sensitivity analyses confirmed these results in propensity score matching adjusted models and in patients with undetectable, or suppressed or unsuppressed renin levels. CONCLUSIONS: At doses that controlled blood pressure and potassium levels, MRAs did not preclude the identification of unilateral PA at AVS. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01234220.

A pilot study proposing an algorithm for pubertal induction in cerebral palsy.

OBJECTIVES: To explore delayed puberty in cerebral palsy (CP) and to test the acceptability of an interventional puberty induction algorithm. METHODS: A two phase cohort study in children and adolescents diagnosed with CP who have delayed puberty. Phase 1: Retrospective review of clinical records and interviews with patients who have been treated with sex-steroids and Phase 2: Prospective interventional trial of pubertal induction with a proposed algorithm of transdermal testosterone (males) or oestrogen (females). Phase 1 examined experiences with sex-steroid treatment. Phase 2 collected data on height adjusted bone mineral density (BMAD), fractures, adverse effects, mobility and quality of life over two years during the induction. RESULTS: Phase 1, treatment was well tolerated in 11/20 treated with sex-steroids; phase 2, using the proposed induction algorithm, 7/10 treated reached Tanner stage 3 by nine months. One participant reached Tanner stage 5 in 24 months. Mean change in BMAD Z-scores was +0.27 % (SD 0.002) in those who could be scanned by dual-energy X-ray absorptiometry (DXA). CONCLUSIONS: Delayed puberty may be diagnosed late. Treatment was beneficial and well tolerated, suggesting all patients with severe pubertal delay or arrest should be considered for sex hormone supplementation.

Efficacy and safety of mineralocorticoid receptor antagonists for the treatment of low-renin hypertension: a systematic review and meta-analysis.

Hypertension is the leading risk factor for premature death. The optimal treatment of low-renin hypertension (LRH), present in 30% of hypertensive individuals, is not known. LRH likely reflects a state of excess salt, expanded volume and/or mineralocorticoid receptor (MR) activation. Therefore, targeted treatment with MR antagonists (MRA) may be beneficial. The objective of this systematic review was to assess the efficacy of MRA therapy in LRH. MEDLINE, Embase and Cochrane databases were searched for randomised controlled trials of adults with LRH that compared the efficacy of MRA to placebo or other antihypertensive treatments. Risk of bias was assessed using the Cochrane risk of bias tool. A meta-analysis was performed using a random-effects model to estimate the difference in blood pressure and the certainty of evidence was assessed using the GRADE approach. The protocol is registered on PROSPERO (CRD42022318763). From the 1612 records identified, 17 studies met the inclusion criteria with a total sample size of 1043 participants. Seven studies (n = 345) were assessed as having a high risk of bias. Meta-analysis indicated that MRA reduced systolic blood pressure by -6.8 mmHg (95% confidence interval -9.6 to -4.1) and -4.8 mmHg (95% confidence interval -11.9 to 2.4) compared to angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (ACEi/ARB) and diuretics. The certainty of the evidence was assessed as moderate and very low, respectively. The findings of this systematic review suggest that MRA is effective in lowering blood pressure in LRH and may be better than ACEi/ARB. Translation to clinical practice is limited by the uncertainty of evidence.

Captopril challenge test: an underutilized test in the diagnosis of primary aldosteronism.

Primary aldosteronism (PA) is the most common cause of endocrine hypertension and is often underdiagnosed. This condition is associated with increased cardiovascular morbidity and mortality in comparison to age and blood pressure matched individuals with essential hypertension (EH). The diagnostic pathway for PA consists of three phases: screening, confirmatory testing, and subtyping. The lack of specificity in the screening step, which relies on the aldosterone to renin ratio, necessitates confirmatory testing. The Endocrine Society's clinical practice guideline suggests four confirmatory tests, including the fludrocortisone suppression test (FST), saline suppression test (SST), captopril challenge test (CCT), and oral sodium loading test (SLT). There is no universally accepted choice of confirmatory test, with practices varying among centers. The SST and FST are commonly used, but they can be resource-intensive, carry risks such as volume overload or hypokalemia, and are contraindicated in severe/uncontrolled HTN as well as in cardiac and renal impairment. In contrast, CCT is a safe and inexpensive alternative that can be performed in an outpatient setting and can be applied when other tests are contraindicated. Despite its simplicity and convenience, the variability in captopril dose, testing posture, and diagnostic threshold limit its widespread use. This narrative review evaluates the diagnostic accuracy of the CCT across different populations, addresses controversies in its usage, and proposes recommendations for its use in the diagnosis of PA. Furthermore, suggestions for future research aimed at promoting the wider utilization of the CCT as a simpler, safer, and more cost-effective diagnostic test are discussed.

The where, who and how of adrenal vein sampling in Australia and New Zealand.

INTRODUCTION: Primary aldosteronism (PA) causes 10-15% of cases of hypertension, and it is increasingly recognised as being under-diagnosed. An interventional radiology procedure, adrenal vein sampling (AVS), is a necessary and important diagnostic procedure for complete workup of PA. There is an anticipated increase in demand for AVS as detection of PA improves. This study aims to describe the current landscape of AVS in Australia and New Zealand (NZ). METHODS: Two surveys exploring AVS methodology and performance were conducted of (i) Endocrinology Unit Heads and (ii) interventional radiologists who perform AVS, at public hospitals with Endocrinology Units across Australia and NZ. RESULTS: Responses were received from 48/53 Endocrinology Unit Heads (91%) and 35 radiologists from 26 sites (87% of AVS sites). AVS was provided at 28/48 Endocrinology sites (58%) across Australia and NZ. In Australia, sites were concentrated in Victoria, New South Wales and Queensland with none in the Northern Territory; in NZ, sites were more evenly distributed across the North and South Islands. AVS was performed by 1-2 dedicated radiologists at 24 sites, 2-3 radiologists at two sites and a rotating roster of radiologists at two sites. Responses to both surveys revealed significant variation in AVS methodology and interpretation of AVS results. CONCLUSION: There is significant heterogeneity in the availability of AVS, the procedural details and the interpretation of results across Australia and NZ, which potentially impacts the quality of patient care and ability to scale up AVS capacity to meet increasing demand.

Diagnostic Delay and Disease Burden in Primary Aldosteronism: An International Patient Survey.

BACKGROUND: Primary aldosteronism (PA) is a common but underdiagnosed cause of hypertension. Many patients experience preventable end-organ injury due to delayed or missed diagnosis but data on the experience of patients are limited. METHODS: We evaluated the lived experience of PA and determines factors associated with diagnostic delay through an international anonymous online cross-sectional survey, codesigned by researchers and PA consumers. We distributed the survey through academic medical centers, Amazon Mechanical Turk, Twitter, PA patient advocacy groups, and hypertension support groups on Facebook between March 21 and June 5, 2022. RESULTS: Of 684 eligible respondents, 66.5% were women. Diagnostic delay (defined as ≥5 years between the diagnosis of hypertension and PA) was reported in 35.6%. Delay was more likely in women than in men (odds ratio, 1.55 [95% CI, 1.10-2.20]) and respondents with ≥3 comorbidities versus none (odds ratio, 1.77 [95% CI, 1.05-3.02]), ≥10 symptoms versus none (odds ratio, 2.73 [95% CI, 1.74-4.44]), and on ≥4 antihypertensive medications versus none (odds ratio, 18.23 [95% CI, 6.24-77.72]). Three-quarters of patients (74.4%) experienced reduced symptom burden following targeted PA treatment. Quality of life improved in 62.3% of patients, and greater improvement was associated with being a woman (odds ratio, 1.42, [95% CI, 1.02-1.97]), receiving adrenalectomy (odds ratio, 2.36 [95% CI, 1.67-3.35]), and taking fewer antihypertensive medications following diagnosis (odds ratio, 5.28 [95% CI, 3.55-7.90]). CONCLUSIONS: One-third of patients with PA experienced prolonged diagnostic delays. Targeted treatment led to reduced symptom burden and improved quality of life. Gender differences in diagnostic delay and symptom burden are prominent. These findings suggest that routine screening for PA at the onset of hypertension may reduce diagnostic delay and facilitate timely diagnosis.

Glucocorticoids with or without fludrocortisone in septic shock: a narrative review from a biochemical and molecular perspective.

Two randomised controlled trials have reported a reduction in mortality when adjunctive hydrocortisone is administered in combination with fludrocortisone compared with placebo in septic shock. A third trial did not support this finding when hydrocortisone administered in combination with fludrocortisone was compared with hydrocortisone alone. The underlying mechanisms for this mortality benefit remain poorly understood. We review the clinical implications and potential mechanisms derived from laboratory and clinical data underlying the beneficial role of adjunctive fludrocortisone with hydrocortisone supplementation in septic shock. Factors including distinct biological effects of glucocorticoids and mineralocorticoids, tissue-specific and mineralocorticoid receptor-independent effects of mineralocorticoids, and differences in downstream signalling pathways between mineralocorticoid and glucocorticoid binding at the mineralocorticoid receptor could contribute to this interaction. Furthermore, pharmacokinetic and pharmacodynamic disparities exist between aldosterone and its synthetic counterpart fludrocortisone, potentially influencing their effects. Pending publication of well-designed, randomised controlled trials, a molecular perspective offers valuable insights and guidance to help inform clinical strategies.

Predicting Bilateral Subtypes of Primary Aldosteronism Without Adrenal Vein Sampling: A Systematic Review and Meta-analysis.

CONTEXT: Primary aldosteronism (PA) is the most common endocrine cause of hypertension. The final diagnostic step involves subtyping, using adrenal vein sampling (AVS), to determine if PA is unilateral or bilateral. The complete PA diagnostic process is time and resource intensive, which can impact rates of diagnosis and treatment. Previous studies have developed tools to predict bilateral PA before AVS. OBJECTIVE: Evaluate the sensitivity and specificity of published tools that aim to identify bilateral subtypes of PA. METHODS: Medline and Embase databases were searched to identify published models that sought to subtype PA, and algorithms to predict bilateral PA are reported. Meta-analysis and meta-regression were then performed. RESULTS: There were 35 studies included, evaluating 55 unique algorithms to predict bilateral PA. The algorithms were grouped into 6 categories: those combining biochemical, radiological, and demographic characteristics (A); confirmatory testing alone or combined with biochemical, radiological, and demographic characteristics (B); biochemistry results alone (C); adrenocorticotropic hormone stimulation testing (D); anatomical imaging (E); and functional imaging (F). Across the identified algorithms, sensitivity and specificity ranged from 5% to 100% and 36% to 100%, respectively. Meta-analysis of 30 unique predictive tools from 32 studies showed that the group A algorithms had the highest specificity for predicting bilateral PA, while group F had the highest sensitivity. CONCLUSIONS: Despite the variability in published predictive algorithms, they are likely important for decision-making regarding the value of AVS. Prospective validation may enable medical treatment upfront for people with a high likelihood of bilateral PA without the need for an invasive and resource-intensive test.

The Concise Guide to PHARMACOLOGY 2023/24: Nuclear hormone receptors.

The Concise Guide to PHARMACOLOGY 2023/24 is the sixth in this series of biennial publications. The Concise Guide provides concise overviews, mostly in tabular format, of the key properties of approximately 1800 drug targets, and nearly 6000 interactions with about 3900 ligands. There is an emphasis on selective pharmacology (where available), plus links to the open access knowledgebase source of drug targets and their ligands (https://www.guidetopharmacology.org/), which provides more detailed views of target and ligand properties. Although the Concise Guide constitutes almost 500 pages, the material presented is substantially reduced compared to information and links presented on the website. It provides a permanent, citable, point-in-time record that will survive database updates. The full contents of this section can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.16179. Nuclear hormone receptors are one of the six major pharmacological targets into which the Guide is divided, with the others being: G protein-coupled receptors, catalytic receptors, enzymes and transporters. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. The landscape format of the Concise Guide is designed to facilitate comparison of related targets from material contemporary to mid-2023, and supersedes data presented in the 2021/22, 2019/20, 2017/18, 2015/16 and 2013/14 Concise Guides and previous Guides to Receptors and Channels. It is produced in close conjunction with the Nomenclature and Standards Committee of the International Union of Basic and Clinical Pharmacology (NC-IUPHAR), therefore, providing official IUPHAR classification and nomenclature for human drug targets, where appropriate.

Poor sleep and shift work associate with increased blood pressure and inflammation in UK Biobank participants.

Disrupted circadian rhythms have been linked to an increased risk of hypertension and cardiovascular disease. However, many studies show inconsistent findings and are not sufficiently powered for targeted subgroup analyses. Using the UK Biobank cohort, we evaluate the association between circadian rhythm-disrupting behaviours, blood pressure (SBP, DBP) and inflammatory markers in >350,000 adults with European white British ancestry. The independent U-shaped relationship between sleep length and SBP/DBP is most prominent with a low inflammatory status. Poor sleep quality and permanent night shift work are also positively associated with SBP/DBP. Although fully adjusting for BMI in the linear regression model attenuated effect sizes, these associations remain significant. Two-sample Mendelian Randomisation (MR) analyses support a potential causal effect of long sleep, short sleep, chronotype, daytime napping and sleep duration on SBP/DBP. Thus, in the current study, we present a positive association between circadian rhythm-disrupting behaviours and SBP/DBP regulation in males and females that is largely independent of age.

Discovery of MK-1468: A Potent, Kinome-Selective, Brain-Penetrant Amidoisoquinoline LRRK2 Inhibitor for the Potential Treatment of Parkinson's Disease.

Genetic mutation of the leucine-rich repeat kinase 2 (LRRK2) protein has been associated with Parkinson's disease (PD), a disabling and progressive neurodegenerative disorder that is devoid of efficacious disease-modifying therapies. Herein, we describe the invention of an amidoisoquinoline (IQ)-derived LRRK2 inhibitor lead chemical series. Knowledge-, structure-, and property-based drug design in concert with rigorous application of in silico calculations and presynthesis predictions enabled the prioritization of molecules with favorable CNS "drug-like" physicochemical properties. This resulted in the discovery of compound 8, which was profiled extensively before human ether-a-go-go (hERG) ion channel inhibition halted its progression. Strategic reduction of lipophilicity and basicity resulted in attenuation of hERG ion channel inhibition while maintaining a favorable CNS efflux transporter profile. Further structure- and property-based optimizations resulted in the discovery of preclinical candidate MK-1468. This exquisitely selective LRRK2 inhibitor has a projected human dose of 48 mg BID and a preclinical safety profile that supported advancement toward GLP toxicology studies.

Structure-function relationships of the aldosterone receptor.

The cellular response to the adrenal steroid aldosterone is mediated by the mineralocorticoid receptor (MR), a member of the nuclear receptor superfamily of ligand-dependent transcription factors. The MR binds more than one physiological ligand with binding at the MR determined by pre-receptor metabolism of glucocorticoid ligands by 11ß hydroxysteroid dehydrogenase type 2. The MR has a wide tissue distribution with multiple roles beyond the classical role in electrolyte homeostasis including cardiovascular function, immune cell signaling, neuronal fate and adipocyte differentiation. The MR has three principal functional domains, an N-terminal ligand domain, a central DNA binding domain and a C-terminal, ligand binding domain, with structures having been determined for the latter two domains but not for the whole receptor. MR signal-transduction can be best viewed as a series of interactions which are determined by the conformation conferred on the receptor by ligand binding. This conformation then determines subsequent intra- and inter-molecular interactions. These interactions include chromatin, coregulators and other transcription factors, and additional less well characterized cytoplasmic non-genomic effects via crosstalk with other signaling pathways. This chapter will provide a review of MR structure and function, and an analysis of the critical interactions involved in MR-mediated signal transduction, which contribute to ligand- and tissue-specificity. Understanding the relevant mechanisms for selective MR signaling in terms of these interactions opens the possibility of novel therapeutic approaches for the treatment of MR-mediated diseases.