Li Ding

Glycogen synthase kinase-3β (GSK-3β) is a downstream target of oncogenic KRas and can accumulate in the nucleus in pancreatic ductal adenocarcinoma (PDA). To determine the interplay between oncogenic KRas and nuclear GSK-3β in PDA development, we generated Lox-STOP-Lox (LSL) nuclear-targeted GSK-3β animals and crossed them with LSL-KRas^G12D mice under the control of the Pdx1-cre transgene—referred to as KNGC. Interestingly, 4-week-old KNGC animals show a profound loss of acinar cells, the expansion of ductal cells, and the rapid development of cystic-like lesions reminiscent of intraductal papillary mucinous neoplasm (IPMN). RNA-sequencing identified the expression of several ductal cell lineage genes including AQP5. Significantly, the Aqp5⁺ ductal cell pool was proliferative, phenotypically distinct from quiescent pancreatic ductal cells, and deletion of AQP5 limited expansion of the ductal pool. Aqp5 is also highly expressed in human IPMN along with GSK-3β highlighting the putative role of Aqp5⁺ ductal cells in human preneoplastic lesion development. Altogether, these data identify nGSK-3β and KRas^G12D as an important signaling node promoting the retention of pancreatic ductal progenitor cells, which could be used to further characterize pancreatic ductal development as well as lineage biomarkers related to IPMN and PDA.

Capsule-based dry powder inhalers (cDPIs) are widely utilized in the delivery of pharmaceutical powders to the lungs. In these systems, the fundamental nature of the interactions between the drug/formulation powder, the capsules, the inhaler device, and the patient must be fully elucidated in order to develop robust manufacturing procedures and provide reproducible lung deposition of the drug payload. Though many commercially available DPIs utilize a capsule-based dose metering system, an in-depth analysis of the critical factors associated with the use of the capsule component has not yet been performed. This review is intended to provide information on critical factors to be considered for the application of a quality by design (QbD) approach for cDPI development. The quality target product profile (QTPP) defines the critical quality attributes (CQAs) which need to be understood to define the critical material attributes (CMA) and critical process parameters (CPP) for cDPI development as well as manufacturing and control.

Niclosamide (NIC) has demonstrated promising in vitro antiviral efficacy against SARS-CoV-2, the causative agent of the COVID-19 pandemic. Though NIC is already FDA-approved, the oral formulation produces systemic drug levels that are too low to inhibit SARS-CoV-2. As an alternative, direct delivery of NIC to the respiratory tract as an aerosol could target the primary site of for SARS-CoV-2 acquisition and spread. We have developed a niclosamide powder suitable for delivery via dry powder inhaler, nebulizer, and nasal spray through the incorporation of human lysozyme (hLYS) as a carrier molecule. This novel formulation exhibits potent in vitro and in vivo activity against MERS-CoV and SARS-CoV-2 and may protect against methicillin-resistance staphylococcus aureus pneumonia and inflammatory lung damage occurring secondary to CoV infections. The suitability of the formulation for all stages of the disease and low-cost development approach will ensure wide-spread utilization

Prader-Willi syndrome (PWS) is a developmental disorder caused by loss of maternally imprinted genes on 15q11-q13, including melanoma antigen gene family member L2 ( MAGEL2 ). The clinical phenotypes of PWS suggest impaired hypothalamic neuroendocrine function; however, the exact cellular defects are unknown. Here, we report deficits in secretory granule (SG) abundance and bioactive neuropeptide production upon loss of MAGEL2 in humans and mice. Unbiased proteomic analysis of Magel2 ^{p Δ /m+} mice revealed a reduction in components of SG in the hypothalamus that was confirmed in 2 PWS patient–derived neuronal cell models. Mechanistically, we show that proper endosomal trafficking by the MAGEL2-regulated WASH complex is required to prevent aberrant lysosomal degradation of SG proteins and reduction of mature SG abundance. Importantly, loss of MAGEL2 in mice, NGN2-induced neurons, and human patients led to reduced neuropeptide production. Thus, MAGEL2 plays an important role in hypothalamic neuroendocrine function, and cellular defects in this pathway may contribute to PWS disease etiology. Moreover, these findings suggest unanticipated approaches for therapeutic intervention.

Intraductal papillary mucinous neoplasm (IPMN) represents one type of pancreatic ductal adenocarcinoma (PDA) precursor lesion, however its cell-of-origin remains unclear. Here we describe a new mouse model in which pancreas-specific Cre activation of a nuclear glycogen synthase kinase-3β transgene is combined with oncogenic KRas (referred to as KNGC). KNGC mice show accumulation of neoplastic ductal cells at 4-weeks that progressively develop into IPMN with low-grade dysplasia in advanced age. RNA-sequencing identified expression of several terminal duct cell lineage genes including Agr2 and Aqp5. Interestingly, Aqp5, a water channel, was found to be required for the development of IPMN lesions in KNGC mice. Staining of human IPMN samples indicates that these preneoplastic lesions also arise from expansion of the terminal duct population. Altogether, these data highlight the utility of the KNGC model for understanding the biology of IPMN and potential utility in defining predictive biomarkers of IPMN – PDA development. Statement of significance: Understanding the cell-of-origin of IPMN is crucial to developing early detection methods that specifically target aggressive precursors of PDA. This work, using a novel mouse model, identifies Aqp5-modulated development of Agr2 ⁺ terminal ducts that could potentially serve as a clinical biomarker for IPMN.

Pancreatic ductal adenocarcinoma (PDAC) is the most common type of pancreatic cancer and is the third leading cause of adult cancer death in the United States with a single-digit 5-year survival rate despite significant advances in understanding the genetics and biology of the disease. Glycogen synthase kinase-3α (GSK-3α) and GSK-3β are serine/threonine kinases encoded by distinct genes that have been shown to localize to the cytoplasm, mitochondria and nucleus. Although they are highly homologous within their kinase domains and known to phosphorylate an overlapping set of target proteins, genetic studies have shown that GSK-3β phosphorylates and regulates the activity of several proteins that participate in pathways that promote neoplastic transformation. Significantly, GSK-3β is progressively overexpressed during PDAC development and has been shown to play an important role in tumor development, progression and resistance to chemotherapy. Thus, novel therapeutic approaches designed to target GSK-3β or the signaling cascades that regulate its expression have become attractive targets for treating PDAC. Areas covered This review describes and summarizes the expanding cellular mechanisms regulating GSK-3β activity, including upstream translational and post-translational regulation, as well as the downstream cellular targets and their functions in PDAC cell growth, cell fate, metastasis and chemotherapeutic resistance. Expert opinion With approximately 100 identified substrates impacting a large number of signaling pathways and transcriptional regulation, the role of GSK-3 kinases are generally considered to be cell- and context-specific. Mutation of the KRas gene is found in over 95% of PDAC patients, where it plays an essential role in PDAC initiation. In addition, oncogenic KRas drives the transcriptional expression of the GSK-3β gene which has been shown to regulate the proliferation and survival of PDAC cells, as well as resistance to various chemotherapies. Thus, the combination of GSK-3 inhibitors with chemotherapeutic drugs could be a promising therapeutic strategy for PDAC.