Systems biology platform for efficient development and translation of multitargeted therapeutics

Failure to achieve efficacy is among the top, if not the most common reason for clinical trial failures. While there may be many underlying contributors to these failures, selecting the right mechanistic hypothesis, the right dose, or the right patient population are the main culprits. Systems biology is an inter-disciplinary field at the intersection of biology and mathematics that has the growing potential to increase probability of success in clinical trials, delivering a data-driven matching of the right mechanism to the right patient, at the right dose. Moreover, as part of successful selection of targets for a therapeutic area, systems biology is a prime approach to development of combination therapies to combating complex diseases, where single targets have failed to achieve sufficient efficacy in the clinic. Systems biology approaches have become increasingly powerful with the progress in molecular and computational methods and represent a novel innovative tool to tackle the complex mechanisms of human disease biology, linking it to clinical phenotypes and optimizing multiple steps of drug discovery and development. With increasing ability of probing biology at a cellular and organ level with omics technologies, systems biology is here to stay and is positioned to be one of the key pillars of drug discovery and development, predicting and advancing the best therapies that can be combined together for an optimal pharmacological effect in the clinic. Here we describe a systems biology platform with a stepwise approach that starts with characterization of the key pathways contributing to the Mechanism of Disease (MOD) and is followed by identification, design, optimization, and translation into the clinic of the best therapies that are able to reverse disease-related pathological mechanisms through one or multiple Mechanisms of Action (MOA)

Sfrp5 Is Not Essential for Axis Formation in the Mouse

Summary: Secreted frizzled related protein (Sfrp) genes encode extracellular factors that can modulate Wnt signaling. During early post-implantation mouse development Sfrp5 is expressed in the anterior visceral endoderm (AVE) and the ventral foregut endoderm. The AVE is important in anterior-posterior axis formation and the ventral foregut endoderm contributes to multiple gut tissues. Here to determine the essential role of Sfrp5 in early mouse development we generated Sfrp5-deficient mice by gene targeting. We report that Sfrp5-deficient mice are viable and fertile. To determine whether the absence of an axis phenotype might be due to genetic redundancy with Dkk1 in the AVE we generated Sfrp5;Dkk1 double mutant mice. AVE development and primitive streak formation appeared normal in Sfrp5 À/À ;Dkk1 embryos. These results indicate that Sfrp5 is not essential for axis formation or foregut morphogenesis in the mouse and also imply that Sfrp5 and Dkk1 together are not essential for AVE development. genesis 44:573-578

Canonical Inflammasomes Drive IFN-γ to Prime Caspase-11 in Defense against a Cytosol-Invasive Bacterium

SummaryThe inflammatory caspases 1 and 11 are activated in response to different agonists and act independently to induce pyroptosis. In the context of IL-1β/IL-18 secretion, however, in vitro studies indicate that caspase-11 acts upstream of NLRP3 and caspase-1. By contrast, studying infection in vivo by the cytosol-invasive bacterium Burkholderia thailandensis, we find that caspase-1 activity is required upstream of caspase-11 to control infection. Caspase-1-activated IL-18 induces IFN-γ to prime caspase-11 and rapidly clear B. thailandensis infection. In the absence of IL-18, bacterial burdens persist, eventually triggering other signals that induce IFN-γ. Whereas IFN-γ was essential, endogenous type I interferons were insufficient to prime caspase-11. Although mice transgenic for caspase-4, the human ortholog of caspase-11, cleared B. thailandensis in vivo, they did not strictly require IFN-γ priming. Thus, caspase-1 provides priming signals upstream of caspase-11 but not caspase-4 during murine defense against a cytosol-invasive bacterium

Caspase-1-induced pyroptosis is an innate immune effector mechanism against intracellular bacteria

Macrophages mediate crucial innate immune responses via caspase-1-dependent processing and secretion of interleukin 1β (IL-1β) and IL-18. Although infection with wild-type Salmonella typhimurium is lethal to mice, we show here that a strain that persistently expresses flagellin was cleared by the cytosolic flagellin-detection pathway through the activation of caspase-1 by the NLRC4 inflammasome; however, this clearance was independent of IL-1β and IL-18. Instead, caspase-1-induced pyroptotic cell death released bacteria from macrophages and exposed the bacteria to uptake and killing by reactive oxygen species in neutrophils. Similarly, activation of caspase-1 cleared unmanipulated Legionella pneumophila and Burkholderia thailandensis by cytokine-independent mechanisms. This demonstrates that activation of caspase-1 clears intracellular bacteria in vivo independently of IL-1β and IL-18 and establishes pyroptosis as an efficient mechanism of bacterial clearance by the innate immune system

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Assembly of tight junctions during early vertebrate development

Tight junction formation during development is critical for embryonic patterning and organization. We consider mechanisms of junction biogenesis in cleaving mouse and Xenopus eggs. Junction assembly follows the establishment of cell polarity at 8-cell (mouse) or 2-cell (Xenopus) stages, characterized by sequential membrane delivery of constituents, coordinated by embryonic (mouse) or maternal (Xenopus) expression programmes. Cadherin adhesion is permissive for tight junction construction only in the mouse. Occludin post-translational modification and membrane delivery, mediated by delayed ZO-1 alpha+isoform expression in the mouse, provides a mechanism for completion of tight junction biogenesis and sealing, regulating the timing of blastocoel cavitation