The interaction of amyloid-beta (Aβ) and tau in the pathogenesis of Alzheimer's disease is a subject of intense inquiry, with the bulk of evidence indicating that changes in tau are downstream of Aβ. It has been shown however, that human tau overexpression in amyloid precursor protein transgenic mice increases Aβ plaque deposition. Here, we confirm that human tau increases Aβ levels. To determine if the observed changes in Aβ levels were because of intracellular or extracellular secreted tau (eTau for extracellular tau), we affinity purified secreted tau from Alzheimer's disease patient-derived cortical neuron conditioned media and analyzed it by liquid chromatography-mass spectrometry. We found the extracellular species to be composed predominantly of a series of N-terminal fragments of tau, with no evidence of C-terminal tau fragments. We characterized a subset of high affinity tau antibodies, each capable of engaging and neutralizing eTau. We found that neutralizing eTau reduces Aβ levels in vitro in primary human cortical neurons where exogenously adding eTau increases Aβ levels. In vivo, neutralizing human tau in 2 human tau transgenic models also reduced Aβ levels. We show that the human tau insert sequence is sufficient to cause the observed increase in Aβ levels. Our data furthermore suggest that neuronal hyperactivity may be the mechanism by which this regulation occurs. We show that neuronal hyperactivity regulates both eTau secretion and Aβ production. Electrophysiological analysis shows for the first time that secreted eTau causes neuronal hyperactivity. Its induction of hyperactivity may be the mechanism by which eTau regulates Aβ production. Together with previous findings, these data posit a novel connection between tau and Aβ, suggesting a dynamic mechanism of positive feed forward regulation. Aβ drives the disease pathway through tau, with eTau further increasing Aβ levels, perpetuating a destructive cycle.

Key Points Cold agglutinin–driven classical pathway activity terminates prior to the initiation of the terminal cascade in CAD patient blood. By inhibiting cold agglutinin–mediated complement deposition on the cellular membrane, TNT003 prevents RBCs from being phagocytosed.

Small cell lung cancer (SCLC) is a devastating neuroendocrine carcinoma. MYCL (L-Myc) is frequently amplified in human SCLC, but its roles in SCLC progression are poorly understood. We isolated preneoplastic neuroendocrine cells from a mouse model of SCLC and found that ectopic expression of L-Myc, c-Myc, or N-Myc conferred tumorforming capacity. We focused on L-Myc, which promoted pre-rRNA synthesis and transcriptional programs associated with ribosomal biogenesis. Deletion of Mycl in two genetically engineered models of SCLC resulted in strong suppression of SCLC. The high degree of suppression suggested that L-Myc may constitute a therapeutic target for a broad subset of SCLC. We then used an RNA polymerase I inhibitor to target rRNA synthesis in an autochthonous Rb/p53-deleted mouse SCLC model and found significant tumor inhibition. These data reveal that activation of RNA polymerase I by L-Myc and other MYC family proteins provides an axis of vulnerability for this recalcitrant cancer.

Background and aims This study aimed to compare real-world clinical effectiveness and safety of vedolizumab, an α4β7-integrin inhibitor, and anti-tumour necrosis factor-α (anti-TNFα) agents in biologic-naïve ulcerative colitis (UC) and Crohn’s disease (CD) patients. Methods This was a 24-month retrospective medical chart study in adult UC and CD patients treated with vedolizumab or anti-TNFα in Canada, Greece and the United States. Inverse probability weighting was used to account for differences between groups. Primary outcomes were cumulative rates of clinical effectiveness (clinical response, clinical remission, mucosal healing) and incidence rates of serious adverse events (SAEs) and serious infections (SIs). Secondary outcomes included cumulative rates of treatment persistence (patients who did not discontinue index treatment during follow-up) and dose escalation and incidence rates of disease exacerbations and disease-related surgeries. Adjusted analyses were performed using inverse probability weighting. Results A total of 1095 patients (604 UC, 491 CD) were included. By 24 months, rates of clinical effectiveness were similar between groups, but incidence rates of SAEs (HR=0.42 [0.28-0.62]) and SIs (HR=0.40 [0.19-0.85]) were significantly lower in vedolizumab vs anti-TNFα patients. Rates of treatment persistence (p<0.01) by 24 months were higher in vedolizumab patients with UC. Incidence rates of disease exacerbations were lower in vedolizumab patients with UC (HR=0.58 [0.45-0.76]). Other outcomes did not significantly differ between groups. Conclusion In this real-world setting, first-line biologic therapy in biologic-naïve patients with UC and CD demonstrated that vedolizumab and anti-TNFα treatments were equally effective at controlling disease symptoms, but vedolizumab has a more favourable safety profile.

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