Efficient generation and transcriptomic profiling of human iPSC-derived pulmonary neuroendocrine cells

Expansion of pulmonary neuroendocrine cells (PNECs) is a pathological feature of many human lung diseases. Human PNECs are inherently difficult to study due to their rarity (\u3c1% of total lung cells) and a lack of established protocols for their isolation. We used induced pluripotent stem cells (iPSCs) to generate induced PNECs (iPNECs), which express core PNEC markers, including ROBO receptors, and secrete major neuropeptides, recapitulating known functions of primary PNECs. Furthermore, we demonstrate that differentiation efficiency is increased in the presence of an air-liquid interface and inhibition of Notch signaling. Single-cell RNA sequencing (scRNA-seq) revealed a PNEC-associated gene expression profile that is concordant between iPNECs and human fetal PNECs. In addition, pseudotime analysis of scRNA-seq results suggests a basal cell origin of human iPNECs. In conclusion, our model has the potential to provide an unlimited source of human iPNECs to explore PNEC pathophysiology associated with several lung diseases

Toward a patient-specific tissue engineered vascular graft

Integrating three-dimensional printing with the creation of tissue-engineered vascular grafts could provide a readily available, patient-specific, autologous tissue source that could significantly improve outcomes in newborns with congenital heart disease. Here, we present the recent case of a candidate for our tissue-engineered vascular graft clinical trial deemed ineligible due to complex anatomical requirements and consider the application of three-dimensional printing technologies for a patient-specific graft. We 3D-printed a closed-disposable seeding device and validated that it performed equivalently to the traditional open seeding technique using ovine bone marrow–derived mononuclear cells. Next, our candidate’s preoperative imaging was reviewed to propose a patient-specific graft. A seeding apparatus was then designed to accommodate the custom graft and 3D-printed on a commodity fused deposition modeler. This exploratory feasibility study represents an important proof of concept advancing progress toward a rationally designed patient-specific tissue-engineered vascular graft for clinical application

Explaining the Nanoscale Effect in the Upconversion Dynamics of β‑NaYF₄:Yb³⁺, Er³⁺ Core and Core–Shell Nanocrystals

Nanocrystals of β-NaYF₄:Yb³⁺, Er³⁺ generally have lower NIR-to-visible upconversion (UC) internal quantum efficiency, IQE, compared to high-quality bulk materials, and exhibit more rapid UC dynamics, typical of quenching, when excited with a pulsed source near 980 nm. The addition of a protective shell increases the IQE of the nanocrystals and slows the overall excited-state dynamics. Here, we show that an extension of a recently developed model for UC in powders of micron-sized β-NaYF₄:18%Yb³⁺, 2%Er³⁺ crystals correctly predicts the time-resolved luminescence curve shapes, relative intensities, and observed drop in IQE of the various emission lines for core and core–shell nanoparticles following pulsed excitation. The model clearly shows that the nanoscale effect on visible upconversion luminescence in these materials, with typical high-Yb³⁺ and low-Er³⁺ doping, is largely due to rapid energy migration among Yb³⁺(²F_5/2) and Er³⁺(⁴I_11/2) ions at the 1 μm energy level, such that an equilibrium is achieved between interior sites and rapidly relaxing surface sites. The faster kinetics observed in visible emission following pulsed NIR excitation is mainly a propagation of the effect of surface quenching of the 1 μm reservoir states and is not due to direct quenching of the visible emitting states themselves. For Er³⁺ ions contributing to UC emission, the relaxation rate constants for the blue (²H_9/2), green (²H_11/2, ⁴S_3/2), and red (⁴F_9/2) emitting states are essentially unchanged from their bulk values, indicating that Er³⁺ ions close to the nanoparticle surface are nearly silent with regard to UC. The addition of a passive β-NaYF₄ shell retards the drain of the 1 μm excitation reservoir and recovers the participation of outer Er³⁺ sites in UC. The dependence of IQE on shell thickness is well explained in terms of a Förster-type model describing an energy donor (Er³⁺, Yb³⁺) interacting with a thin plane layer of acceptors (oleate). The UC behavior of both the core and the core–shell nanocrystals can be modeled, almost quantitatively, solely on the basis of quenching at the 1 μm level, without separate consideration of a near-surface Er³⁺ population. However, a two-layer model for the core nanoparticles is revealing with regard to the modest extent to which near-surface ions do participate in UC and gives a better representation of the detailed dynamics of the NIR emitting states. A method is presented for allowing investigators to estimate the IQE for any nanosample (with 18% Yb³⁺, 2%Er³⁺ doping) as a function of excitation power density (cw) or pulse-energy density based on the low pulse energy measurement of the decay constant for the 1 μm emission

ALS motor neurons exhibit hallmark metabolic defects that are rescued by SIRT3 activation

10.1038/s41418-020-00664-0Cell Death and Differentiation2841379-139

Lactobacillus Strains Alleviated Hyperlipidemia and Liver Steatosis in Aging Rats via Activation of AMPK

In this study, we hypothesized that different strains of Lactobacillus can alleviate hyperlipidemia and liver steatosis via activation of 5′ adenosine monophosphate-activated protein kinase (AMPK), an enzyme that is involved in cellular energy homeostasis, in aged rats. Male rats were fed with a high-fat diet (HFD) and injected with D-galactose daily over 12 weeks to induce aging. Treatments included (n = 6) (i) normal diet (ND), (ii) HFD, (iii) HFD-statin (lovastatin 2 mg/kg/day), (iv) HFD-Lactobacillus fermentum DR9 (10 log CFU/day), (v) HFD-Lactobacillus plantarum DR7 (10 log CFU/day), and (vi) HFD-Lactobacillus reuteri 8513d (10 log CFU/day). Rats administered with statin, DR9, and 8513d reduced serum total cholesterol levels after eight weeks (p < 0.05), while the administration of DR7 reduced serum triglycerides level after 12 weeks (p < 0.05) as compared to the HFD control. A more prominent effect was observed from the administration of DR7, where positive effects were observed, ranging from hepatic gene expressions to liver histology as compared to the control (p < 0.05); downregulation of hepatic lipid synthesis and β-oxidation gene stearoyl-CoA desaturase 1 (SCD1), upregulation of hepatic sterol excretion genes of ATP-binding cassette subfamily G member 5 and 8 (ABCG5 and ABCG8), lesser degree of liver steatosis, and upregulation of hepatic energy metabolisms genes AMPKα1 and AMPKα2. Taken altogether, this study illustrated that the administration of selected Lactobacillus strains led to improved lipid profiles via activation of energy and lipid metabolisms, suggesting the potentials of Lactobacillus as a promising natural intervention for alleviation of cardiovascular and liver diseases