The impact of the California state lockdown during the COVID-19 pandemic on management of patients with pancreatic ductal adenocarcinoma.

BACKGROUND AND OBJECTIVES: The SARS-COVID-19 pandemic significantly limited healthcare access. We sought to evaluate whether California's lockdown in March 2020 affected staging and time to treatment of pancreatic ductal adenocarcinoma (PDAC). We hypothesized that patients diagnosed after the lockdown would have longer time to treatment and higher stage at presentation. METHODS: We retrospectively identified and categorized 1294 patients presenting to five University of California healthcare systems with a new diagnosis of PDAC into "pre-lockdown" and "post-lockdown" groups based on timing of pathologic diagnosis. RESULTS: In the 12 months pre-lockdown, 835 patients were diagnosed with PDAC, and 459 patients in the 6 months post-lockdown. Demographics, staging, and treatment type were similar between eras. There was a decreased male:female ratio post- versus pre-lockdown (0.97 vs. 1.25; p = 0.03). Time from symptom onset to first treatment was significantly increased among females post-lockdown (p = 0.001). However, overall time from diagnosis to first treatment was shorter in the post-lockdown era (median 23 vs. 26 days, p < 0.001). CONCLUSIONS: The COVID-19 lockdown did not significantly delay initial presentation, diagnosis, or treatment of newly diagnosed PDAC patients. Time from diagnosis to first treatment was shorter post-lockdown. Reduced healthcare utilization for minor complaints and increased telehealth utilization may have contributed.

Current and Novel Biologic Therapies for Patients with Asthma and Nasal Polyps.

A substantial portion of asthma and nasal polyps (NPs) share a common pathogenesis, which includes type 2-mediated inflammation. Distinct endotypes and phenotypes characterizing asthma and chronic rhinosinusitis have been identified. With emerging evidence describing pathophysiology, novel targets for biologic monoclonal antibody treatments have been developed. There are currently six biologic therapies approved by the US Food and Drug Administration to treat asthma, including omalizumab, mepolizumab, reslizumab, benralizumab, dupilumab, and tezepelumab, three of these-omalizumab, mepolizumab, and dupilumab-are also approved for NPs.

DNA recognition and induced genome modification by a hydroxymethyl-γ tail-clamp peptide nucleic acid.

Peptide nucleic acids (PNAs) can target and stimulate recombination reactions in genomic DNA. We have reported that γPNA oligomers possessing the diethylene glycol γ-substituent show improved efficacy over unmodified PNAs in stimulating recombination-induced gene modification. However, this structural modification poses a challenge because of the inherent racemization risk in O-alkylation of the precursory serine side chain. To circumvent this risk and improve γPNA accessibility, we explore the utility of γPNA oligomers possessing the hydroxymethyl-γ moiety for gene-editing applications. We demonstrate that a γPNA oligomer possessing the hydroxymethyl modification, despite weaker preorganization, retains the ability to form a hybrid with the double-stranded DNA target of comparable stability and with higher affinity than that of the diethylene glycol-γPNA. When formulated into poly(lactic-co-glycolic acid) nanoparticles, the hydroxymethyl-γPNA stimulates higher frequencies (≥ 1.5-fold) of gene modification than the diethylene glycol γPNA in mouse bone marrow cells.

Long-acting and extended-release implant and nanoformulations with a synergistic antiretroviral two-drug combination controls HIV-1 infection in a humanized mouse model.

The HIV pandemic has affected over 38 million people worldwide with close to 26 million currently accessing antiretroviral therapy (ART). A major challenge in the long-term treatment of HIV-1 infection is nonadherence to ART. Long-acting antiretroviral (LA-ARV) formulations, that reduce dosing frequency to less than once a day, are an urgent need that could tackle the adherence issue. Here, we have developed two LA-ART interventions, one an injectable nanoformulation, and the other, a removable implant, for the delivery of a synergistic two-drug ARV combination comprising a pre-clinical nonnucleoside reverse transcriptase inhibitor (NNRTI), Compound I, and the nucleoside reverse transcriptase inhibitor (NRTI), 4'-ethynyl-2-fluoro-2'-deoxyadenosine. The nanoformulation is poly(lactide-co-glycolide)-based and the implant is a copolymer of ω-pentadecalactone and p-dioxanone, poly(PDL-co-DO), a novel class of biocompatible, biodegradable materials. Both the interventions, packaged independently with each ARV, released sustained levels of the drugs, maintaining plasma therapeutic indices for over a month, and suppressed viremia in HIV-1-infected humanized mice for up to 42 days with maintenance of CD4+ T cells. These data suggest promise in the use of these new drugs as LA-ART formulations in subdermal implant and injectable mode.

Purine nucleoside phosphorylase enables dual metabolic checkpoints that prevent T cell immunodeficiency and TLR7-associated autoimmunity.

Purine nucleoside phosphorylase (PNP) enables the breakdown and recycling of guanine nucleosides. PNP insufficiency in humans is paradoxically associated with both immunodeficiency and autoimmunity, but the mechanistic basis for these outcomes is incompletely understood. Here, we identify two immune lineage-dependent consequences of PNP inactivation dictated by distinct gene interactions. During T cell development, PNP inactivation is synthetically lethal with downregulation of the dNTP triphosphohydrolase SAMHD1. This interaction requires deoxycytidine kinase activity and is antagonized by microenvironmental deoxycytidine. In B lymphocytes and macrophages, PNP regulates Toll-like receptor 7 signaling by controlling the levels of its (deoxy)guanosine nucleoside ligands. Overriding this regulatory mechanism promotes germinal center formation in the absence of exogenous antigen and accelerates disease in a mouse model of autoimmunity. This work reveals that one purine metabolism gene protects against immunodeficiency and autoimmunity via independent mechanisms operating in distinct immune lineages and identifies PNP as a potentially novel metabolic immune checkpoint.

Nanoparticles for delivery of agents to fetal lungs.

Fetal treatment of congenital lung disease, such as cystic fibrosis, surfactant protein syndromes, and congenital diaphragmatic hernia, has been made possible by improvements in prenatal diagnostic and interventional technology. Delivery of therapeutic agents to fetal lungs in nanoparticles improves cellular uptake. The efficacy and safety of nanoparticle-based fetal lung therapy depends on targeting of necessary cell populations. This study aimed to determine the relative distribution of nanoparticles of a variety of compositions and sizes in the lungs of fetal mice delivered through intravenous and intra-amniotic routes. Intravenous delivery of particles was more effective than intra-amniotic delivery for epithelial, endothelial and hematopoietic cells in the fetal lung. The most effective targeting of lung tissue was with 250nm Poly-Amine-co-Ester (PACE) particles accumulating in 50% and 44% of epithelial and endothelial cells. This study demonstrated that route of delivery and particle composition impacts relative cellular uptake in fetal lung, which will inform future studies in particle-based fetal therapy.

Nanoparticle-mediated convection-enhanced delivery of a DNA intercalator to gliomas circumvents temozolomide resistance.

In patients with glioblastoma, resistance to the chemotherapeutic temozolomide (TMZ) limits any survival benefits conferred by the drug. Here we show that the convection-enhanced delivery of nanoparticles containing disulfide bonds (which are cleaved in the reductive environment of the tumour) and encapsulating an oxaliplatin prodrug and a cationic DNA intercalator inhibit the growth of TMZ-resistant cells from patient-derived xenografts, and hinder the progression of TMZ-resistant human glioblastoma tumours in mice without causing any detectable toxicity. Genome-wide RNA profiling and metabolomic analyses of a glioma cell line treated with the cationic intercalator or with TMZ showed substantial differences in the signalling and metabolic pathways altered by each drug. Our findings suggest that the combination of anticancer drugs with distinct mechanisms of action with selective drug release and convection-enhanced delivery may represent a translational strategy for the treatment of TMZ-resistant gliomas.

The N-glycome regulates the endothelial-to-hematopoietic transition.

Definitive hematopoietic stem and progenitor cells (HSPCs) arise from the transdifferentiation of hemogenic endothelial cells (hemECs). The mechanisms of this endothelial-to-hematopoietic transition (EHT) are poorly understood. We show that microRNA-223 (miR-223)-mediated regulation of N-glycan biosynthesis in endothelial cells (ECs) regulates EHT. miR-223 is enriched in hemECs and in oligopotent nascent HSPCs. miR-223 restricts the EHT of lymphoid-myeloid lineages by suppressing the mannosyltransferase alg2 and sialyltransferase st3gal2, two enzymes involved in protein N-glycosylation. ECs that lack miR-223 showed a decrease of high mannose versus sialylated sugars on N-glycoproteins such as the metalloprotease Adam10. EC-specific expression of an N-glycan Adam10 mutant or of the N-glycoenzymes phenocopied miR-223 mutant defects. Thus, the N-glycome is an intrinsic regulator of EHT, serving as a key determinant of the hematopoietic fate.

Optimizing biodegradable nanoparticle size for tissue-specific delivery.

Nanoparticles (NPs) are promising vehicles for drug delivery because of their potential to target specific tissues [1]. Although it is known that NP size plays a critical role in determining their biological activity, there are few quantitative studies of the role of NP size in determining biodistribution after systemic administration. Here, we engineered fluorescent, biodegradable poly(lactic-co-glycolic acid) (PLGA) NPs in a range of sizes (120-440nm) utilizing a microfluidic platform and used these NPs to determine the effect of diameter on bulk tissue and cellular distribution after systemic administration. We demonstrate that small NPs (∼120nm) exhibit enhanced uptake in bulk lung and bone marrow, while larger NPs are sequestered in the liver and spleen. We also show that small NPs (∼120nm) access specific alveolar cell populations and hematopoietic stem and progenitor cells more readily than larger NPs. Our results suggest that size of PLGA NPs can be used to tune delivery to certain tissues and cell populations in vivo.

Structural and pharmacological evaluation of a novel non-nucleoside reverse transcriptase inhibitor as a promising long acting nanoformulation for treating HIV.

Combination antiretroviral therapy (cART) has been proven effective in inhibiting human immunodeficiency virus type 1 (HIV-1) infection and has significantly improved the health outcomes in acquired immune deficiency syndrome (AIDS) patients. The therapeutic benefits of cART have been challenged because of the toxicity and emergence of drug-resistant HIV-1 strains along with lifelong patient compliance resulting in non-adherence. These issues also hinder the clinical benefits of non-nucleoside reverse transcriptase inhibitors (NNRTIs), which are one of the vital components of cART for the treatment of HIV-1 infection. In this study, using a computational and structural based drug design approach, we have discovered an effective HIV -1 NNRTI, compound I (Cmpd I) that is very potent in biochemical assays and which targets key residues in the allosteric binding pocket of wild-type (WT)-RT as revealed by structural studies. Furthermore, Cmpd I exhibited very potent antiviral activity in HIV-1 infected T cells, lacked cytotoxicity (therapeutic index >100,000), and no significant off-target effects were noted in pharmacological assays. To address the issue of non-adherence, we developed a long-acting nanoformulation of Cmpd I (Cmpd I-NP) using poly (lactide-coglycolide) (PLGA) particles. The pharmacokinetic studies of free and nanoformulated Cmpd I were carried out in BALB/c mice. Intraperitoneal administration of Cmpd I and Cmpd I-NP in BALB/c mice revealed prolonged serum residence time of 48 h and 30 days, respectively. The observed serum concentrations of Cmpd I in both cases were sufficient to provide >97% inhibition in HIV-1 infected T-cells. The significant antiviral activity along with favorable pharmacological and pharmacokinetic profile of Cmpd I, provide compelling and critical support for its further development as an anti-HIV therapeutic agent.