Discovery and Preclinical Characterization of BIIB129, a Covalent, Selective, and Brain-Penetrant BTK Inhibitor for the Treatment of Multiple Sclerosis.

Multiple sclerosis (MS) is a chronic disease with an underlying pathology characterized by inflammation-driven neuronal loss, axonal injury, and demyelination. Bruton's tyrosine kinase (BTK), a nonreceptor tyrosine kinase and member of the TEC family of kinases, is involved in the regulation, migration, and functional activation of B cells and myeloid cells in the periphery and the central nervous system (CNS), cell types which are deemed central to the pathology contributing to disease progression in MS patients. Herein, we describe the discovery of BIIB129 (25), a structurally distinct and brain-penetrant targeted covalent inhibitor (TCI) of BTK with an unprecedented binding mode responsible for its high kinome selectivity. BIIB129 (25) demonstrated efficacy in disease-relevant preclinical in vivo models of B cell proliferation in the CNS, exhibits a favorable safety profile suitable for clinical development as an immunomodulating therapy for MS, and has a low projected total human daily dose.

Two cases of atraumatic adrenal hemorrhage: A review of active management, conservative management, and challenges faced.

Adrenal hemorrhage (AH) is an uncommon and potentially disastrous affliction that carries an accepted mortality risk of 15%. Variable symptomatology can cause a diagnostic dilemma and may be missed. We present 2 cases of right-sided AH; both cases were initially presumed to be renal colic. Case 1 was an 86-year-old gentleman, presenting with right flank pain found to have a right-sided atraumatic AH. He presented with hemorrhagic shock, requiring angioembolization of the bleeding vessel. Case 2 was a 62-year-old gentleman who presented with right flank pain and was found to have a right-sided atraumatic AH. He was hemodynamically stable and successfully managed conservatively. Adrenal hemorrhage is a potentially fatal affliction that may be missed. CT scans are the recommended imaging modality during an acute presentation due to wider availability and fast assessment. We demonstrate a hemodynamically stable patient managed with a 'watch and wait' approach and an unstable patient managed with resuscitation followed by urgent angioembolization.

Amyand's hernia with concurrent appendicitis: A case of interval laparoscopic herniorrhaphy and literature review.

INTRODUCTION AND IMPORTANCE: Amyand's hernia with concurrent appendicitis is rare, with a reported incidence of 0.13 % of all inguinal hernias. This condition is challenging to diagnose and manage and no optimal treatment has been established. CASE PRESENTATION: A 71-year-old man presented with an acutely painful, tender, and irreducible right inguinal hernia. He had a history of a right inguinal hernia for several months and had undergone open left inguinal hernia repair. The patient had no other medical comorbidities. Blood test results were nonspecific, with a C-reactive protein of 90 mg/L. Ultrasound scan suggested a strangulated right inguinal hernia. Laparoscopy revealed an Amyand's hernia with concurrent appendicitis and a pus-filled right inguinal hernia sac. The patient underwent laparoscopic appendicectomy, followed by staged laparoscopic transabdominal preperitoneal right inguinal hernia repair with mesh after eight weeks to reduce mesh infection. Histopathological examination confirmed acute uncomplicated appendicitis without perforation or malignancy. The patient had an unremarkable post-operative recovery. DISCUSSION: This case highlights the diagnostic challenges associated with Amyand's hernia and concurrent appendicitis. Laparoscopy provides both diagnostic and therapeutic opportunities. In this case, laparoscopic mesh herniorrhaphy was delayed and staged until local hernia sac inflammation resolved following appendicectomy. CONCLUSION: Surgeons should have an index of suspicion for Amyand's hernia given the heterogeneity of presentations. A case-by-case approach is required to prevent post-operative complications and determine the safe timing of definitive hernia repair when the inguinal hernial sac is inflamed. Further research is required to provide surgeons with evidence-based approaches for this unique condition.

Considerations from an International Regulatory and Pharmaceutical Industry (IQ MPS Affiliate) Workshop on the Standardization of Complex In Vitro Models in Drug Development.

In May 2022, there is an International Regulatory and Pharmaceutical Industry (Innovation and Quality [IQ] Microphysiological Systems [MPS] Affiliate) Workshop on the standardization of complex in vitro models (CIVMs) in drug development. This manuscript summarizes the discussions and conclusions of this joint workshop organized and executed by the IQ MPS Affiliate and the United States Food and Drug Administration (FDA). A key objective of the workshop is to facilitate discussions around opportunities and/or needs for standardization of MPS and chart potential pathways to increase model utilization in the context of regulatory decision making. Participation in the workshop included 200 attendees from the FDA, IQ MPS Affiliate, and 26 global regulatory organizations and affiliated parties representing Europe, Japan, and Canada. It is agreed that understanding global perspectives regarding the readiness of CIVM/MPS models for regulatory decision making and potential pathways to gaining acceptance is useful to align on globally. The obstacles are currently too great to develop standards for every context of use (COU). Instead, it is suggested that a more tractable approach may be to think of broadly applicable standards that can be applied regardless of COU and/or organ system. Considerations and next steps for this effort are described.

Challenges in managing upper gastrointestinal bleeding secondary to primary squamous cell carcinoma of the pancreas: a case report and literature review.

BACKGROUND: Primary pancreatic squamous cell carcinoma (SCC) is a rare type of pancreatic cancer, with an incidence of 5% of all pancreatic cancers. This condition is associated with a poor prognosis, and no optimal treatment has been established (Zhang et al. in Medicine (Baltim). 97:e12253, 2018). CASE PRESENTATION: A 56-year-old man presented to our hospital with upper gastrointestinal bleeding and new-onset diabetes mellitus. He had no other medical comorbidities, episodes of pancreatitis and symptoms secondary to pancreatic insufficiency. A computed tomography (CT) scan showed a 94 × 72 × 83 mm necrotic pancreatic body mass with gastric invasion and multiple liver metastases. Gastroscopy revealed deep ulcerations at the posterior wall of the stomach with an active slow ooze. Endoscopic ultrasound was performed with EUS guided biopsy, which confirmed poorly differentiated squamous carcinoma of the pancreas. The patient underwent palliative radiotherapy for recurrent upper gastrointestinal bleeding followed by palliative chemotherapy with gemcitabine and nab-paclitaxel. He was referred to dietitians and diabetes educators for the management of pancreatic exocrine and endocrine insufficiency before being referred to community palliative care upon discharge. CONCLUSIONS: This is the first reported Australian case of pancreatic SCC presenting with upper gastrointestinal bleeding and new-onset diabetes mellitus. Patients with unresectable disease require a multidisciplinary approach to manage complications and improve symptom control. However, there are no standard treatment guidelines and future research is needed in this regard.

Applications of microphysiological systems to disease models in the biopharmaceutical industry: Opportunities and challenges.

Disease models enable researchers to investigate, test, and identify therapeutic targets that would alter the patients' disease condition and improve quality of life. Advances in genetic alteration and analytical techniques have enabled rapid devel­opment of disease models using preclinical animals and cell cultures. However, success rates of drug development remain low due to limited recapitulation of clinical pathophysiology by these models. To resolve this challenge, the pharmaceutical industry has explored microphysiological system (MPS) disease models, which are complex in vitro systems that include but are not limited to organ-on-a-chip, organoids, spheroids, and 3D bioengineered tissues (e.g., 3D printing, hydrogels). Capable of integrating key in vivo properties, such as disease-relevant human cells, multi-cellularity/dimensionality of organs, and/or well-controlled physical and molecular cues, MPS disease models are being developed for a variety of indications. With on-going qualifications or validations for wide adoption within the pharmaceutical industry, MPS disease models hold exciting potential to enable in-depth investigation of in vivo pathophysiology and enhance drug discovery and development processes. To introduce the present status of MPS disease models, this paper describes notable examples in six disease areas: cancer, liver/kidney diseases, respiratory diseases/COVID-19, neurodegenerative diseases, gastrointestinal diseases, and select rare diseases. Additionally, we describe current technical limitations and provide recommendations for future development that would expand application opportunities within the pharmaceutical industry.

Assessment of a 3D neural spheroid model to detect pharmaceutical-induced neurotoxicity.

Drug-induced neurotoxicity is a leading cause of safety-related attrition for therapeutics in clinical trials, often driven by poor predictivity of preclinical in vitro and in vivo models of neurotoxicity. Over a dozen different iPSC-derived 3D spheroids have been described in recent years, but their ability to predict neurotoxicity in patients has not been evaluated nor compared with the predictive power of nonclinical species. To assess the predictive capabilities of human iPSC-derived neural spheroids (microBrains), we used 84 structurally diverse pharmaceuticals with robust clinical and pre-clinical datasets with varying degrees of seizurogenic and neurodegenerative liability. Drug-induced changes in neural viability and phenotypic calcium bursts were assessed using 7 endpoints based on calcium oscillation profiles and cel-lular ATP levels. These endpoints, normalized by therapeutic exposure, were used to build logistic regression models to establish endpoint cutoffs and evaluate probability for clinical neurotoxicity. The neurotoxicity score calculated from the logistic regression model could distinguish neurotoxic from non-neurotoxic clinical molecules with a specificity as high as 93.33% and a sensitivity of 53.49%, demonstrating a very low false positive rate for the prediction of seizures, convulsions, and neurodegeneration. In contrast, nonclinical species showed a higher sensitivity (75%) but much lower specificity (30.4%). The neural spheroids demonstrated higher likelihood ratio positive and inverse likelihood ratio neg-ative values compared with nonclinical safety studies. This assay has the potential to be used as a predictive assay to detect neurotoxicity in early drug discovery, aiding in the early identification of compounds that eventually may fail due to neurotoxicity.

Evaluation of palliative treatments in unresectable pancreatic cancer.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) presents as unresectable disease in 80% of patients. Limited Australian data exists regarding management and outcome of palliative management for PDAC. This study aims to: (i) identify patients with PDAC being managed with palliative intent; (ii) assess the type of palliative management being used. METHODS: A prospectively maintained pancreatic database at Western Health (2015-2017) was used to identify patient demographics; stage and multidisciplinary decision regarding resectability and operative interventions; palliative care; use of chemotherapy, radiotherapy and; management of exocrine and endocrine insufficiency. Data on chemotherapy use, number of hospital admissions, emergency department attendances and intensive care unit admissions 30 days prior to death were recorded. RESULTS: One-hundred and eleven patients had diagnosis of PDAC, 15% with locally advanced and 45% with metastatic PDAC. Among the locally advanced and metastatic PDAC, 48% received biliary stent insertions, 93% had palliative care referral, 45% received palliative chemotherapy and 10% received radiotherapy. Dietitian referral occurred in 79% and 36% were prescribed with a pancreatic enzyme replacement therapy. Diabetes mellitus was present in 52% of which 31% was new onset. Within 30 days prior to death, 11% patients received palliative chemotherapy, 32% were hospitalized and 11% visited an emergency department more than once. Sixty-five percent died in hospital. CONCLUSION: A high proportion of patients diagnosed with locally advanced and metastatic PDAC received palliative care referrals and appropriate level of end-of-life care. Further prospective studies are necessary, examining the management and impacts of pancreatic insufficiency in this group.

Hybrid abdominal robotic approach with conventional transanal total mesorectal excision (TaTME) for rectal cancer: feasibility and outcomes from a single institution.

Total mesorectal excision (TME) is currently recognised as the standard of care for patients with rectal cancer. Complete TME is known to be associated with lower rates of recurrence. Robotic and endoscopic TaTME approaches are reported to offer excellent proximal and distal rectal dissection into the TME plane, however, combining both approaches in a hybrid procedure could potentially optimise visualisation of the dissection plane and confer improved circumferential and distal margin rates. The aim of this study was to analyse the feasibility of a hybrid robotic abdominal approach with conventional TaTME for rectal cancer. Furthermore, pathological and patient outcomes were assessed. A review of prospectively maintained databases was undertaken to assess all patients undergoing robotic TME surgery for rectal tumours from August 2016 to October 2017. Patient demographics, tumour characteristics and outcomes were collated from patient charts and hospital databases. All patients underwent a modified Cecil approach after multidisciplinary team discussion. Eight patients (7 male, 1 female) underwent a combined hybrid approach with a median age of 60 years (range 47-73) and BMI of 29.5 (range 20-39.1) kg/m2. Median distance from the anorectal junction (ARJ) was 7.5 (range 4-13) cm. Six patients underwent neoadjuvant treatment with chemoradiotherapy. Patients had a median length of stay (LOS) of 9 (range 4-33) days. There were no intra-operative complications encountered and no patients required a conversion to an open procedure. Complications included one anastomotic leak and one presacral collection. All patients had a complete TME with RO resection with a median number of lymph nodes harvested was 22 (range 6-37) lymph nodes. This hybrid technique is a feasible, practical and operatively favourable approach to rectal cancer surgery with initial pathological outcomes and complication profile equivalent to other approaches.

Myosin IIA-mediated forces regulate multicellular integrity during vascular sprouting.

Angiogenic sprouting is a critical process involved in vascular network formation within tissues. During sprouting, tip cells and ensuing stalk cells migrate collectively into the extracellular matrix while preserving cell-cell junctions, forming patent structures that support blood flow. Although several signaling pathways have been identified as controlling sprouting, it remains unclear to what extent this process is mechanoregulated. To address this question, we investigated the role of cellular contractility in sprout morphogenesis, using a biomimetic model of angiogenesis. Three-dimensional maps of mechanical deformations generated by sprouts revealed that mainly leader cells, not stalk cells, exert contractile forces on the surrounding matrix. Surprisingly, inhibiting cellular contractility with blebbistatin did not affect the extent of cellular invasion but resulted in cell-cell dissociation primarily between tip and stalk cells. Closer examination of cell-cell junctions revealed that blebbistatin impaired adherens-junction organization, particularly between tip and stalk cells. Using CRISPR/Cas9-mediated gene editing, we further identified NMIIA as the major isoform responsible for regulating multicellularity and cell contractility during sprouting. Together, these studies reveal a critical role for NMIIA-mediated contractile forces in maintaining multicellularity during sprouting and highlight the central role of forces in regulating cell-cell adhesions during collective motility.

Extracellular matrix alignment dictates the organization of focal adhesions and directs uniaxial cell migration.

Physical features of the extracellular matrix (ECM) heavily influence cell migration strategies and efficiency. Migration in and on fibrous ECMs is of significant physiologic importance, but limitations in the ability to experimentally define the diameter, density, and alignment of native ECMs in vitro have hampered our understanding of how these properties affect this basic cell function. Here, we designed a high-throughput in vitro platform that models fibrous ECM as collections of lines of cell-adhesive fibronectin on a flat surface to eliminate effects of dimensionality and topography. Using a microcontact printing approach to orthogonally vary line alignment, density, and size, we determined each factor's individual influence on NIH3T3 fibroblast migration. High content imaging and statistical analyses revealed that ECM alignment is the most critical parameter in influencing cell morphology, polarization, and migratory behavior. Specifically, increasing ECM alignment led cells to adopt an elongated uniaxial morphology and migrate with enhanced speed and persistence. Intriguingly, migration speeds were tightly correlated with the organization of focal adhesions, where cells with the most aligned adhesions migrated fastest. Highly organized focal adhesions and associated actin stress fibers appeared to define the number and location of protrusive fronts, suggesting that ECM alignment influences active Rac1 localization. Utilizing a novel microcontact-printing approach that lacks confounding influences of substrate dimensionality, mechanics, or differences in the adhesive area, this work highlights the effect of ECM alignment on orchestrating the cytoskeletal machinery that governs directed uniaxial cell migration.

Matrix degradability controls multicellularity of 3D cell migration.

A major challenge in tissue engineering is the development of materials that can support angiogenesis, wherein endothelial cells from existing vasculature invade the surrounding matrix to form new vascular structures. To identify material properties that impact angiogenesis, here we have developed an in vitro model whereby molded tubular channels inside a synthetic hydrogel are seeded with endothelial cells and subjected to chemokine gradients within a microfluidic device. To accomplish precision molding of hydrogels and successful integration with microfluidics, we developed a class of hydrogels that could be macromolded and micromolded with high shape and size fidelity by eliminating swelling after polymerization. Using this material, we demonstrate that matrix degradability switches three-dimensional endothelial cell invasion between two distinct modes: single-cell migration and the multicellular, strand-like invasion required for angiogenesis. The ability to incorporate these tunable hydrogels into geometrically constrained settings will enable a wide range of previously inaccessible biomedical applications.The fabrication of vascularized 3D tissues requires an understanding of how material properties govern endothelial cell invasion into the surrounding matrix. Here the authors integrate a non-swelling synthetic hydrogel with a microfluidic device to study chemokine gradient-driven angiogenic sprouting and find that matrix degradability modulates the collectivity of cell migration.

A proteomic approach reveals integrin activation state-dependent control of microtubule cortical targeting.

Integrin activation, which is regulated by allosteric changes in receptor conformation, enables cellular responses to the chemical, mechanical and topological features of the extracellular microenvironment. A global view of how activation state converts the molecular composition of the region proximal to integrins into functional readouts is, however, lacking. Here, using conformation-specific monoclonal antibodies, we report the isolation of integrin activation state-dependent complexes and their characterization by mass spectrometry. Quantitative comparisons, integrating network, clustering, pathway and image analyses, define multiple functional protein modules enriched in a conformation-specific manner. Notably, active integrin complexes are specifically enriched for proteins associated with microtubule-based functions. Visualization of microtubules on micropatterned surfaces and live cell imaging demonstrate that active integrins establish an environment that stabilizes microtubules at the cell periphery. These data provide a resource for the interrogation of the global molecular connections that link integrin activation to adhesion signalling.

A DNA-based molecular probe for optically reporting cellular traction forces.

We developed molecular tension probes (TPs) that report traction forces of adherent cells with high spatial resolution, can in principle be linked to virtually any surface, and obviate monitoring deformations of elastic substrates. TPs consist of DNA hairpins conjugated to fluorophore-quencher pairs that unfold and fluoresce when subjected to specific forces. We applied TPs to reveal that cellular traction forces are heterogeneous within focal adhesions and localized at their distal edges.

Fluid shear stress threshold regulates angiogenic sprouting.

The density and architecture of capillary beds that form within a tissue depend on many factors, including local metabolic demand and blood flow. Here, using microfluidic control of local fluid mechanics, we show the existence of a previously unappreciated flow-induced shear stress threshold that triggers angiogenic sprouting. Both intraluminal shear stress over the endothelium and transmural flow through the endothelium above 10 dyn/cm(2) triggered endothelial cells to sprout and invade into the underlying matrix, and this threshold is not impacted by the maturation of cell-cell junctions or pressure gradient across the monolayer. Antagonizing VE-cadherin widened cell-cell junctions and reduced the applied shear stress for a given transmural flow rate, but did not affect the shear threshold for sprouting. Furthermore, both transmural and luminal flow induced expression of matrix metalloproteinase 1, and this up-regulation was required for the flow-induced sprouting. Once sprouting was initiated, continuous flow was needed to both sustain sprouting and prevent retraction. To explore the potential ramifications of a shear threshold on the spatial patterning of new sprouts, we used finite-element modeling to predict fluid shear in a variety of geometric settings and then experimentally demonstrated that transmural flow guided preferential sprouting toward paths of draining interstitial fluid flow as might occur to connect capillary beds to venules or lymphatics. In addition, we show that luminal shear increases in local narrowings of vessels to trigger sprouting, perhaps ultimately to normalize shear stress across the vasculature. Together, these studies highlight the role of shear stress in controlling angiogenic sprouting and offer a potential homeostatic mechanism for regulating vascular density.

Jostling for position in angiogenic sprouts: continuous rearrangement of cells explained by differential adhesion dynamics.

Endothelial sprouting during angiogenesis is a highly coordinated morphogenetic process that involves polarized tip cells leading stalk cells to form new capillaries. While tip and stalk cells previously were thought to be stable and have static phenotypes within the sprout, it is becoming increasingly clear that endothelial cells undergo dynamic rearrangements. A new study using computer simulations, validated by in vitro and in vivo experimental data, now provides an explanation for these rearrangements, showing that sprouting cells are in a continuum of migratory states, regulated by differential cell-cell adhesions and protrusive activities to drive proper vascular organization.

Rac1 is deactivated at integrin activation sites through an IQGAP1-filamin-A-RacGAP1 pathway.

Cell migration makes a fundamental contribution to both normal physiology and disease pathogenesis. Integrin engagement with extracellular ligands spatially controls, via the cyclical activation and deactivation of the small GTPase Rac1, the dynamic membrane protrusion and cytoskeletal reorganization events that are required for directional migration. Although the pathways that control integrin-mediated Rac1 activation are reasonably well defined, the mechanisms that are responsible for switching off activity are poorly understood. Here, proteomic analysis of activated integrin-associated complexes suggests filamin-A and IQ-motif-containing GTPase-activating protein 1 (IQGAP1) as candidates that link ß1 integrin to Rac1. siRNA-mediated knockdown of either filamin-A or IQGAP1 induced high, dysregulated Rac1 activity during cell spreading on fibronectin. Using immunoprecipitation and immunocytochemistry, filamin-A and IQGAP1 were shown to be part of a complex that is recruited to active ß1 integrin. Mass spectrometric analysis of individual filamin-A, IQGAP1 and Rac1 pull-downs and biochemical analysis, identified RacGAP1 as a novel IQGAP1 binding partner. Further immunoprecipitation and immunocytochemistry analyses demonstrated that RacGAP1 is recruited to IQGAP1 and active ß1 integrin, and that suppression of RacGAP1 expression triggered elevated Rac1 activity during spreading on fibronectin. Consistent with these findings, reduced expression of filamin-A, IQGAP1 or RacGAP1 triggered unconstrained membrane protrusion and disrupted directional cell migration on fibrillar extracellular matrices. These findings suggest a model whereby integrin engagement, followed by filamin-A, IQGAP1 and RacGAP1 recruitment, deactivates Rac1 to constrain its activity spatially and thereby coordinate directional cell migration.

Biomimetic model to reconstitute angiogenic sprouting morphogenesis in vitro.

Angiogenesis is a complex morphogenetic process whereby endothelial cells from existing vessels invade as multicellular sprouts to form new vessels. Here, we have engineered a unique organotypic model of angiogenic sprouting and neovessel formation that originates from preformed artificial vessels fully encapsulated within a 3D extracellular matrix. Using this model, we screened the effects of angiogenic factors and identified two distinct cocktails that promoted robust multicellular endothelial sprouting. The angiogenic sprouts in our system exhibited hallmark structural features of in vivo angiogenesis, including directed invasion of leading cells that developed filopodia-like protrusions characteristic of tip cells, following stalk cells exhibiting apical-basal polarity, and lumens and branches connecting back to the parent vessels. Ultimately, sprouts bridged between preformed channels and formed perfusable neovessels. Using this model, we investigated the effects of angiogenic inhibitors on sprouting morphogenesis. Interestingly, the ability of VEGF receptor 2 inhibition to antagonize filopodia formation in tip cells was context-dependent, suggesting a mechanism by which vessels might be able to toggle between VEGF-dependent and VEGF-independent modes of angiogenesis. Like VEGF, sphingosine-1-phosphate also seemed to exert its proangiogenic effects by stimulating directional filopodial extension, whereas matrix metalloproteinase inhibitors prevented sprout extension but had no impact on filopodial formation. Together, these results demonstrate an in vitro 3D biomimetic model that reconstitutes the morphogenetic steps of angiogenic sprouting and highlight the potential utility of the model to elucidate the molecular mechanisms that coordinate the complex series of events involved in neovascularization.

Multidimensional traction force microscopy reveals out-of-plane rotational moments about focal adhesions.

Recent methods have revealed that cells on planar substrates exert both shear (in-plane) and normal (out-of-plane) tractions against the extracellular matrix (ECM). However, the location and origin of the normal tractions with respect to the adhesive and cytoskeletal elements of cells have not been elucidated. We developed a high-spatiotemporal-resolution, multidimensional (2.5D) traction force microscopy to measure and model the full 3D nature of cellular forces on planar 2D surfaces. We show that shear tractions are centered under elongated focal adhesions whereas upward and downward normal tractions are detected on distal (toward the cell edge) and proximal (toward the cell body) ends of adhesions, respectively. Together, these forces produce significant rotational moments about focal adhesions in both protruding and retracting peripheral regions. Temporal 2.5D traction force microscopy analysis of migrating and spreading cells shows that these rotational moments are highly dynamic, propagating outward with the leading edge of the cell. Finally, we developed a finite element model to examine how rotational moments could be generated about focal adhesions in a thin lamella. Our model suggests that rotational moments can be generated largely via shear lag transfer to the underlying ECM from actomyosin contractility applied at the intracellular surface of a rigid adhesion of finite thickness. Together, these data demonstrate and probe the origin of a previously unappreciated multidimensional stress profile associated with adhesions and highlight the importance of new approaches to characterize cellular forces.