Inhibition of MALT1 and BCL2 Induces Synergistic Antitumor Activity in Models of B-Cell Lymphoma.

The activated B cell (ABC) subset of diffuse large B-cell lymphoma (DLBCL) is characterized by chronic B-cell receptor signaling and associated with poor outcomes when treated with standard therapy. In ABC-DLBCL, MALT1 is a core enzyme that is constitutively activated by stimulation of the B-cell receptor or gain-of-function mutations in upstream components of the signaling pathway, making it an attractive therapeutic target. We discovered a novel small-molecule inhibitor, ABBV-MALT1, that potently shuts down B-cell signaling selectively in ABC-DLBCL preclinical models leading to potent cell growth and xenograft inhibition. We also identified a rational combination partner for ABBV-MALT1 in the BCL2 inhibitor, venetoclax, which when combined significantly synergizes to elicit deep and durable responses in preclinical models. This work highlights the potential of ABBV-MALT1 monotherapy and combination with venetoclax as effective treatment options for patients with ABC-DLBCL.

Differential Gene Expression following DHX36/G4R1 Knockout Is Associated with G-Quadruplex Content and Cancer.

G-quadruplexes (G4s) are secondary DNA and RNA structures stabilized by positive cations in a central channel formed by stacked tetrads of Hoogsteen base-paired guanines. G4s form from G-rich sequences across the genome, whose biased distribution in regulatory regions points towards a gene-regulatory role. G4s can themselves be regulated by helicases, such as DHX36 (aliases: G4R1 and RHAU), which possess the necessary activity to resolve these stable structures. G4s have been shown to both positively and negatively regulate gene expression when stabilized by ligands, or through the loss of helicase activity. Using DHX36 knockout Jurkat cell lines, we identified widespread, although often subtle, effects on gene expression that are associated with the presence or number of observed G-quadruplexes in promoters or gene regions. Genes that significantly change their expression, particularly those that show a significant increase in RNA abundance under DHX36 knockout, are associated with a range of cellular functions and processes, including numerous transcription factors and oncogenes, and are linked to several cancers. Our work highlights the direct and indirect role of DHX36 in the transcriptome of T-lymphocyte leukemia cells and the potential for DHX36 dysregulation in cancer.

The lifesaving effects of cardiac adhesions.

Patients that incur myocardial disruption from penetrating cardiac injuries have an average 6%-10% expectancy rate of reaching the hospital alive. If prompt recognition on arrival is not immediate, the morbidity and mortality are significantly higher due to the secondary physiologic sequalae of either cardiogenic or hemorrhagic shock. Even after a triumphant arrival at a medical facility, out of that 6%-10%, half of those patients are not expected to survive. The unique significance of the presenting case breaks this tradition, expanding past the paradigms and issuing an exceptional understanding of the protective effects that cardiac surgery can futuristically cause through preformed adhesions. In our case, the cardiac adhesions achieved this by containing a penetrating cardiac injury that had caused complete ventricular disruption.

COVID-19-related arterio-ureteral fistula formation in a post-transplant patient.

Arterio-ureteral fistulas (AUF) are extremely rare and are not commonly suspected in the setting of patients with post-renal allograft transplantation. The diagnosis, while uncommon, can be potentially lethal which is only exacerbated by the clinical conundrum associated with their under-recognition and various treatment algorithms. This case identifies a unique patient with a history of 2 failed renal transplants who presents with new onset intermittent hematuria after contracting coronavirus disease 2019 (COVID-19). Despite the patient having his second renal transplant graft embolized, the patient continued to present with refractory hematuria, leading to the realization and identification of an AUF to his right renal graft. This sequence of events brings forth a case of unique significance, underscoring the potential ramifications that COVID-19 poses to the renal transplant population.

Denitrative Hydroxylation of Unactivated Nitroarenes.

A one-step method for the conversion of nitroarenes into phenols under operationally simple, transition-metal-free conditions is described. This denitrative functionalization protocol provides a concise and economical alternative to conventional three-step synthetic sequences. Experimental and computational studies suggest that nitroarenes may be substituted by an electron-catalysed radical-nucleophilic substitution (SRN 1) chain mechanism.

Drug repurposing based on a quantum-inspired method versus classical fingerprinting uncovers potential antivirals against SARS-CoV-2.

The COVID-19 pandemic has accelerated the need to identify new antiviral therapeutics at pace, including through drug repurposing. We employed a Quadratic Unbounded Binary Optimization (QUBO) model, to search for compounds similar to Remdesivir, the first antiviral against SARS-CoV-2 approved for human use, using a quantum-inspired device. We modelled Remdesivir and compounds present in the DrugBank database as graphs, established the optimal parameters in our algorithm and resolved the Maximum Weighted Independent Set problem within the conflict graph generated. We also employed a traditional Tanimoto fingerprint model. The two methods yielded different lists of lead compounds, with some overlap. While GS-6620 was the top compound predicted by both models, the QUBO model predicted BMS-986094 as second best. The Tanimoto model predicted different forms of cobalamin, also known as vitamin B12. We then determined the half maximal inhibitory concentration (IC50) values in cell culture models of SARS-CoV-2 infection and assessed cytotoxicity. We also demonstrated efficacy against several variants including SARS-CoV-2 Strain England 2 (England 02/2020/407073), B.1.1.7 (Alpha), B.1.351 (Beta) and B.1.617.2 (Delta). Lastly, we employed an in vitro polymerization assay to demonstrate that these compounds directly inhibit the RNA-dependent RNA polymerase (RdRP) of SARS-CoV-2. Together, our data reveal that our QUBO model performs accurate comparisons (BMS-986094) that differed from those predicted by Tanimoto (different forms of vitamin B12); all compounds inhibited replication of SARS-CoV-2 via direct action on RdRP, with both models being useful. While Tanimoto may be employed when performing relatively small comparisons, QUBO is also accurate and may be well suited for very complex problems where computational resources may limit the number and/or complexity of possible combinations to evaluate. Our quantum-inspired screening method can therefore be employed in future searches for novel pharmacologic inhibitors, thus providing an approach for accelerating drug deployment.

Drug repurposing based on a Quantum-Inspired method versus classical fingerprinting uncovers potential antivirals against SARS-CoV-2 including vitamin B12.

The COVID-19 pandemic has accelerated the need to identify new therapeutics at pace, including through drug repurposing. We employed a Quadratic Unbounded Binary Optimization (QUBO) model, to search for compounds similar to Remdesivir (RDV), the only antiviral against SARS-CoV-2 currently approved for human use, using a quantum-inspired device. We modelled RDV and compounds present in the DrugBank database as graphs, established the optimal parameters in our algorithm and resolved the Maximum Weighted Independent Set problem within the conflict graph generated. We also employed a traditional Tanimoto fingerprint model. The two methods yielded different lists of compounds, with some overlap. While GS-6620 was the top compound predicted by both models, the QUBO model predicted BMS-986094 as second best. The Tanimoto model predicted different forms of cobalamin, also known as vitamin B12. We then determined the half maximal inhibitory concentration (IC 50 ) values in cell culture models of SARS-CoV-2 infection and assessed cytotoxicity. Lastly, we demonstrated efficacy against several variants including SARS-CoV-2 Strain England 2 (England 02/2020/407073), B.1.1.7 (Alpha), B.1.351 (Beta) and B.1.617.2 (Delta). Our data reveal that BMS-986094 and different forms of vitamin B12 are effective at inhibiting replication of all these variants of SARS-CoV-2. While BMS-986094 can cause secondary effects in humans as established by phase II trials, these findings suggest that vitamin B12 deserves consideration as a SARS-CoV-2 antiviral, particularly given its extended use and lack of toxicity in humans, and its availability and affordability. Our screening method can be employed in future searches for novel pharmacologic inhibitors, thus providing an approach for accelerating drug deployment.

The RNA helicase DHX36-G4R1 modulates C9orf72 GGGGCC hexanucleotide repeat-associated translation.

GGGGCC (G4C2) hexanucleotide repeat expansions in the endosomal trafficking gene C9orf72 are the most common genetic cause of ALS and frontotemporal dementia. Repeat-associated non-AUG (RAN) translation of this expansion through near-cognate initiation codon usage and internal ribosomal entry generates toxic proteins that accumulate in patients' brains and contribute to disease pathogenesis. The helicase protein DEAH-box helicase 36 (DHX36-G4R1) plays active roles in RNA and DNA G-quadruplex (G4) resolution in cells. As G4C2 repeats are known to form G4 structures in vitro, we sought to determine the impact of manipulating DHX36 expression on repeat transcription and RAN translation. Using a series of luciferase reporter assays both in cells and in vitro, we found that DHX36 depletion suppresses RAN translation in a repeat length-dependent manner, whereas overexpression of DHX36 enhances RAN translation from G4C2 reporter RNAs. Moreover, upregulation of RAN translation that is typically triggered by integrated stress response activation is prevented by loss of DHX36. These results suggest that DHX36 is active in regulating G4C2 repeat translation, providing potential implications for therapeutic development in nucleotide repeat expansion disorders.

Chest imaging of hypersensitivity pneumonitis induced by heroin abuse.

Long-term abuse of nasally inhaled substances such as heroin can result in life-threatening hypersensitivity pneumonitis and respiratory distress. In the setting of hypoxia, a chest CTA is often necessary to see the extent of the lung involvement and to rule out pulmonary emboli.

Two pulmonary emboli in a psych pod.

BACKGROUND: A female patient known to have schizoaffective disorder self-presented to an emergency department in a state of acute agitation and paranoia shortly after a 35-day inpatient stay at a psychiatric facility. CASE REPORT: The patient exhibited no signs or complaints of dyspnea or hypoxia, but later collapsed and became hypoxic after sleeping comfortably with sedation for 12 h in the psychiatric unit. She was intubated and a computed tomography angiogram revealed bilateral lobar pulmonary emboli and right heart strain. CONCLUSION: Psychiatric hospitalizations, medications, diagnoses and relevant sequelae increase venous thromboembolism risk more than many realize.

G-Quadruplex Helicase DHX36/G4R1 Engages Nuclear Lamina Proteins in Quiescent Breast Cancer Cells.

G-quadruplexes (G4s) are nucleic acid structures found enriched within gene regulatory sequences. G4s control fundamental cellular processes, including replication, transcription, and translation. Proto-oncogenes are enriched with G4 sequences, while tumor-suppressor genes are depleted, suggesting roles for G4s in cell survival and proliferation. Specialized helicases participate in G4-mediated gene regulation via enzymatic unwinding activity. One such enzyme, DHX36/G4R1, is the major G4-helicase and is a master regulator of G4-DNAs and mRNAs. G4-resolution promotes the expression of proproliferative genes; as such, DHX36/G4R1 promotes cell proliferation. Little is known about how DHX36/G4R1 itself is regulated in nondividing cells. We hypothesized that DHX36/G4R1 protein binding partners are altered when a cell transitions from a dividing to a quiescent state. We found that DHX36/G4R1 co-purifies with a distinct set of proteins under quiescent conditions, which may represent a novel complex that regulates DHX36/G4R1 during cell cycle transitions and have implications for development and cancer.

An odontoid fracture and vertebral artery injury in fast-track.

While CT scans without IV contrast are obtained commonly to evaluate vertebral injuries, CT angiography scans should be considered whenever a fracture site approaches known vasculature.

microRNA-184 is induced by store-operated calcium entry and regulates early keratinocyte differentiation.

Extracellular calcium (Ca2+ ) and store-operated Ca2+ entry (SOCE) govern homoeostasis in the mammalian epidermis. Multiple microRNAs (miRNA) also regulate epidermal differentiation, and raised external Ca2+ modulates the expression of several such miRNAs in keratinocytes. However, little is known about the regulation of miR-184 in keratinocytes or the roles of miR-184 in keratinocyte differentiation. Here we report that exogenous Ca2+ stimulates miR-184 expression in primary epidermal keratinocytes and that this occurs in a SOCE-dependent manner. Levels of miR-184 were raised by about 30-fold after exposure to 1.5 mM Ca2+ for 5 days. In contrast, neither phorbol ester nor 1,25-dihydroxyvitamin D3 had any effect on miR-184 levels. Pharmacologic and genetic inhibitors of SOCE abrogated Ca2+ -dependent miR-184 induction by 70% or more. Ectopic miR-184 inhibited keratinocyte proliferation and led to a fourfold increase in the expression of involucrin, a marker of early keratinocyte differentiation. Exogenous miR-184 also triggered a threefold rise in levels of cyclin E and doubled the levels of γH2AX, a marker of DNA double-strand breaks. The p21 cyclin-dependent kinase inhibitor, which supports keratinocyte growth arrest, was also induced by miR-184. Together our findings point to an SOCE:miR-184 pathway that targets a cyclin E/DNA damage regulatory node to facilitate keratinocyte differentiation.

Loss of protein quality control gene UBR1 sensitizes Saccharomyces cerevisiae to the aminoglycoside hygromycin B.

Ubr1 is a conserved ubiquitin ligase involved in the degradation of aberrant proteins in eukaryotic cells. The human enzyme is found mutated in patients with Johanson-Blizzard syndrome. We hypothesized that Ubr1 is necessary for optimal cellular fitness in conditions associated with elevated abundance of aberrant and misfolded proteins. Indeed, we found that loss of Ubr1 in the model eukaryotic microorganism Saccharomyces cerevisiae strongly sensitizes cells to hygromycin B, which reduces translational fidelity by causing ribosome A site distortion. Our results are consistent with a prominent role for Ubr1 in protein quality control. We speculate that disease manifestations in patients with Johanson-Blizzard syndrome are linked, at least in part, to defects in protein quality control caused by loss of Ubr1 function.

Phosphaturic mesenchymal tumor: Case report.

Phosphaturic mesenchymal tumors (PMT) are an extremely rare pathologic phenomenon that presents as paraneoplastic tumor-induced osteomalacia. Their diagnosis is often significantly delayed due to their rare occurrence in addition to the generalized and vague symptoms of their presentation including progressive bone pain, myopathies, arthralgias, fractures, and generalized weakness. This case report identifies a very characteristic presentation of a 37-year old African American male suffering from a PMT; with symptom onset presenting over 5-years prior to presentation with a consistent complaint of progressive and debilitating quadriparesis. The tumor was first identified by pelvic computerized tomography, although it was initially thought to be a noncontributory benign soft tissue mass. It was only after being hospitalized due to a severe and unresponsive hypophosphatemic state (less than 1 mg/dl) that the collective differential switched to one of a PMT with follow up nuclear 99mTc bone scintigraphy and magnetic resonance imaging being used to aid in the overall assessment of changes, extent, and general metabolic properties of the tumor. The confirmatory diagnosis of a PMT was later established through both serum fibroblast growth factor 23 testing and histopathologic review of the surgically removed specimen. By including this rare but curative disease into the differential of osteomalacia and thereby further examining patient serum phosphate levels, the previous 5-7 year delay in diagnosis will be dramatically reduced.

A Diagnosis of Adult-Onset Still's Disease after Multiple Urgent Care Visits.

A 34-year-old man with recent treatment and resolution of community-acquired pneumonia presents to the emergency department with protracted fever, rash, and sore throat. Sustained fever and greater than two-fold increase in leukocytosis despite appropriate antibiotic therapy prompted hospital admission for infectious disease and rheumatologic evaluations which ultimately revealed adult-onset Still's disease, a rare autoinflammatory disorder with potentially life-threatening complications.

A smartphone, a slit lamp, and an ophthalmology consult.

Clinicians should always consider capturing images with their phone when possible so that key clinical findings seen in the real-time physical examination can be memorialized in the electronic medical record.

Spontaneous Intracranial and Lumbar Subdural Hematoma Presenting as Vaginal Pain.

BACKGROUND: Spontaneous spinal and intracranial subdural hematomas are rarely reported, especially occurring simultaneously. Anticoagulation use has been associated with spontaneous hemorrhages. Prompt diagnosis is required to prevent permanent neurological sequelae. In this case report, we describe a spontaneous spinal and intracranial subdural hematoma in a woman taking warfarin and initially presenting with severe vaginal pain. CASE REPORT: A 42-year-old woman who had a history of mechanical valve replacement and was therefore taking warfarin, came to an emergency department for relief of severe vaginal pain. Mild concurrent lumbar pain increased concern about spinal pathology, so magnetic resonance imaging of her spine was performed. It revealed a subdural hematoma extending from L1-S1 with arachnoiditis, which suggested intracranial pathology, though the patient had no complaint of a headache. Computed tomography of her brain demonstrated a large right subdural hemorrhage with midline shift. Subsequent imaging revealed no aneurysm or source of the intracranial bleeding. We concluded that the patient experienced spontaneous anticoagulation-related intracranial hemorrhage resulting in lumbar subdural hematoma and arachnoiditis with referred vaginal pain. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Pelvic, vaginal, or perineal pain may be the presenting symptom in patients with lower spinal pathology. It is important to consider causes other than gynecological ones in the differential diagnosis of these patients, as well as to be cognizant of the relationship between spinal and intracranial subdural hemorrhages. In patients with back pain or radiating lumbar pain, especially coupled with neurological effects, clinicians should consider spinal subdural hemorrhage and arachnoiditis to expedite imaging studies and treatment of these rare entities.