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Since the start of the pandemic, information on potential therapeutic options have been rapidly disseminated on an almost daily basis, often with incomplete or conflicting results and without adequate peer review. Due to the high first‐pass hepatic extraction of phosphoramidates and expected low bioavailability, oral administration of remdesivir was not explored. 9 In respiratory epithelial cells, GS‐441524 is further converted by intracellular esterases into the pharmacologically active nucleoside triphosphate (GS‐443902), which competes with naturally occurring adenosine phosphate and functions as a delayed RNA‐dependent RNA polymerase inhibitor. 7 Although the plasma half‐lives of remdesivir and the intermediate metabolite are short (~ 0.5–1 hour), the plasma and intracellular half‐lives of the GS‐441524 are long (~ 24 and 40 hours, respectively) allowing for once‐daily dosing. Remdesivir is also a weak inhibitor of CYP3A4, OATP1B1, OATP1B3, bile acid export pump, multidrug resistance‐associated protein 4, and sodium‐taurocholate cotransporter protein. According to the website (accessed May 4, 2020), co‐administration of strong CYP3A4 inhibitors, such as voriconazole, is labeled as “no clinically significant interaction expected.”

Exosomes and extracellular vesicles (EV) are increasingly being explored as circulating biomarkers, but their heterogenous composition will likely mandate the development of multiplexed EV technologies. Iteratively multiplexed analyses of near single EVs have been challenging to implement beyond a few colors during spectral sensing. Here we developed a multiplexed analysis of EV technique (MASEV) to interrogate thousands of individual EVs during 5 cycles of multi-channel fluorescence staining for 15 EV biomarkers. Contrary to the common belief, we show that: several markers proposed to be ubiquitous are less prevalent than believed; multiple biomarkers concur in single vesicles but only in small fractions; affinity purification can lead to loss of rare EV subtypes; and deep profiling allows detailed analysis of EV, potentially improving the diagnostic content. These findings establish the potential of MASEV for uncovering fundamental EV biology and heterogeneity and increasing diagnostic specificity. Multiplexed analyses of near single EVs is currently challenging. Here the authors report the method MASEV, multiplexed analysis of EVs, to interrogate thousands of individual EVs during 5 cycles of multi-channel fluorescence staining for 15 EV biomarkers.

Therapeutic nanoparticles (TNPs) aim to deliver drugs more safely and effectively to cancers, yet clinical results have been unpredictable owing to limited in vivo understanding. Here we use single-cell imaging of intratumoral TNP pharmacokinetics and pharmacodynamics to better comprehend their heterogeneous behaviour. Model TNPs comprising a fluorescent platinum(IV) pro-drug and a clinically tested polymer platform (PLGA- b -PEG) promote long drug circulation and alter accumulation by directing cellular uptake toward tumour-associated macrophages (TAMs). Simultaneous imaging of TNP vehicle, its drug payload and single-cell DNA damage response reveals that TAMs serve as a local drug depot that accumulates significant vehicle from which DNA-damaging Pt payload gradually releases to neighbouring tumour cells. Correspondingly, TAM depletion reduces intratumoral TNP accumulation and efficacy. Thus, nanotherapeutics co-opt TAMs for drug delivery, which has implications for TNP design and for selecting patients into trials. Drug-loaded nanoparticles allow controlled release and enhanced delivery, yet understanding in vivo behavior has been difficult. Here, the authors develop a platinum prodrug coupled to a polymer platform, and use intravital imaging to show that the nanoparticle accumulates in macrophages, from the which drug redistributes to neighboring tumour cells.

Increased use of cross-sectional imaging has resulted in frequent detection of incidental cystic pancreatic lesions. Serous cystadenomas (SCAs) are benign cysts that do not require surgical intervention unless symptomatic. Unfortunately, up to half of SCAs do not have typical imaging findings (“atypical SCAs”), overlap with potentially malignant precursor lesions, and thus pose a diagnostic challenge. We tested whether the analysis of circulating extracellular vesicle (EV) biomarkers using a digital EV screening technology (DEST) could enhance the discrimination of cystic pancreatic lesions and avoid unnecessary surgical intervention in these atypical SCAs. Analysis of 25 different protein biomarkers in plasma EV from 68 patients identified a putative biomarker signature of Das-1, Vimentin, Chromogranin A, and CAIX with high discriminatory power (AUC of 0.99). Analysis of plasma EV for multiplexed markers may thus be helpful in clinical decision-making.

Targeting DNA repair pathways is a powerful strategy to treat cancers. To gauge efficacy in vivo , typical response markers include late stage effects such as tumor shrinkage, progression free survival, or invasive repeat biopsies. These approaches are often difficult to answer critical questions such as how a given drug affects single cell populations as a function of dose and time, distance from microvessels or how drug concentration (pharmacokinetics) correlates with DNA damage (pharmacodynamics). Here, we established a single-cell in vivo pharmacodynamic imaging read-out based on a truncated 53BP1 double-strand break reporter to determine whether or not poly(ADP-ribose) polymerase (PARP) inhibitor treatment leads to accumulation of DNA damage. Using this reporter, we show that not all PARP inhibitor treated tumors incur an increase in DNA damage. The method provides a framework for single cell analysis of cancer therapeutics in vivo .

Mitochondria, which are essential organelles in resting and replicating cells, can vary in number, mass and shape. Past research has primarily focused on short-term molecular mechanisms underlying fission/fusion. Less is known about longer-term mitochondrial behavior such as the overall makeup of cell populations’ morphological patterns and whether these patterns can be used as biomarkers of drug response in human cells. We developed an image-based analytical technique to phenotype mitochondrial morphology in different cancers, including cancer cell lines and patient-derived cancer cells. We demonstrate that (i) cancer cells of different origins, including patient-derived xenografts, express highly diverse mitochondrial phenotypes; (ii) a given phenotype is characteristic of a cell population and fairly constant over time; (iii) mitochondrial patterns correlate with cell metabolic measurements and (iv) therapeutic interventions can alter mitochondrial phenotypes in drug-sensitive cancers as measured in pre- versus post-treatment fine needle aspirates in mice. These observations shed light on the role of mitochondrial dynamics in the biology and drug response of cancer cells. On the basis of these findings, we propose that image-based mitochondrial phenotyping can provide biomarkers for assessing cancer phenotype and drug response.

During pregnancy, women often become insulin resistant, thus requiring an expansion of pancreatic beta cell mass to provide more insulin. Michael German and his colleagues now report that lactogenic hormones drive the expression of serotonin in the beta cells to induce this increase in beta cell mass. During pregnancy, the energy requirements of the fetus impose changes in maternal metabolism. Increasing insulin resistance in the mother maintains nutrient flow to the growing fetus, whereas prolactin and placental lactogen counterbalance this resistance and prevent maternal hyperglycemia by driving expansion of the maternal population of insulin-producing beta cells 1 , 2 , 3 . However, the exact mechanisms by which the lactogenic hormones drive beta cell expansion remain uncertain. Here we show that serotonin acts downstream of lactogen signaling to stimulate beta cell proliferation. Expression of serotonin synthetic enzyme tryptophan hydroxylase-1 (Tph1) and serotonin production rose sharply in beta cells during pregnancy or after treatment with lactogens in vitro . Inhibition of serotonin synthesis by dietary tryptophan restriction or Tph inhibition blocked beta cell expansion and induced glucose intolerance in pregnant mice without affecting insulin sensitivity. Expression of the Gα q -linked serotonin receptor 5-hydroxytryptamine receptor-2b (Htr2b) in maternal islets increased during pregnancy and normalized just before parturition, whereas expression of the Gα i -linked receptor Htr1d increased at the end of pregnancy and postpartum. Blocking Htr2b signaling in pregnant mice also blocked beta cell expansion and caused glucose intolerance. These studies reveal an integrated signaling pathway linking beta cell mass to anticipated insulin need during pregnancy. Modulators of this pathway, including medications and diet, may affect the risk of gestational diabetes 4 .

Background Radiation therapy often leads to late radiation-induced skin fibrosis (RISF), causing movement impairment and discomfort. We conducted a comprehensive study to assess the effectiveness of metformin and adipose-derived stem cells (ASCs), whether autologous or allogeneic, individually or in combination therapy, in mitigating RISF. Methods Using a female C57BL/6J mouse model subjected to hind limb irradiation as a representative RISF model, we evaluated metformin, ASCs, or their combination in two contexts: prophylactic (started on day 1 post-irradiation) and therapeutic (initiated on day 14 post-irradiation, coinciding with fibrosis symptoms). We measured limb movement, examined skin histology, and analyzed gene expression to assess treatment efficacy. Results Prophylactic metformin and ASCs, whether autologous or allogeneic, effectively prevented late fibrosis, with metformin showing promising results. However, combination therapy did not provide additional benefits when used prophylactically. Autologous ASCs, alone or with metformin, proved most effective against late-stage RISF. Prophylactic intervention outperformed late therapy for mitigating radiation skin damage. Co-culture studies revealed that ASCs and metformin downregulated inflammation and fibrotic gene expression in both mouse and human fibroblasts. Conclusions Our study suggests metformin's potential as a prophylactic measure to prevent RISF, and the combination of ASCs and metformin holds promise for late-stage RISF treatment. These findings have clinical implications for improving the quality of life for those affected by radiation-induced skin fibrosis.

Background: Autologous fat transfer in the form of lipoaspirates for the reconstruction of the breast after breast cancer surgery is a commonly used procedure in plastic surgery. However, concerns regarding the oncologic risk of nutrient-rich fat tissue are widely debated. Previous studies have primarily focused on studying the interaction between adipose-derived stem cells (ASCs) and breast cancer cells. Methods: In this study, we performed a comprehensive analysis of the paracrine- and contact-based interactions between lipoaspirates, ASCs and breast cancer cell lines. An inverted flask culture method was used to study the contact-based interaction between lipoaspirates and breast cancer cells, while GFP-expressing breast cancer cell lines were generated to study the cell–cell contact interaction with ASCs. Three different human breast cancer cell lines, MCF-7, MDA-MB-231 and BT-474, were studied. We analyzed the impact of these interactions on the proliferation, cell cycle and epithelial-to-mesenchymal (EMT) transition of the breast cancer cells. Results: Our results revealed that both lipoaspirates and ASCs do not increase the proliferation rate of the breast cancer cells either through paracrine- or contact-dependent interactions. We observed that lipoaspirates selectively inhibit the proliferation of MCF-7 cells in contact co-culture, driven by the retinoblastoma (Rb) protein activity mediating cell cycle arrest. Additionally, ASCs inhibited MDA-MB-231 breast cancer cell proliferation in cell–cell contact-dependent interactions. Quantitative real-time PCR revealed no significant increase in the EMT-related genes in breast cancer cells upon co-culture with ASCs. Conclusion: In conclusion, this study provides evidence of the non-oncogenic character of lipoaspirates and supports the safety of clinical fat grafting in breast reconstruction after oncological surgical procedures. In vivo studies in appropriate animal models and long-term post-operative clinical data from patients are essential to reach the final safety recommendations.

We report a case of a 53-year-old HIV-negative patient in San Francisco, California, USA, with no classic mpox prodromal symptoms or skin lesions who experienced fulminant, vision-threatening scleritis, keratitis, and uveitis. Deep sequence analysis identified monkeypox virus RNA in the aqueous humor. We confirmed the virus on the cornea and sclera by PCR.