Light field camera calibration and point spread function calculation based on differentiable ray tracing.

The imaging process of the light field (LF) camera with a micro-lens array (MLA) may suffer from multiple aberrations. It is thus difficult to precisely calibrate the intrinsic hardware parameters and calculate the corresponding point spread function (PSF). To build an aberration-aware solution with better generalization, we propose an end-to-end imaging model based on the differentiable ray tracing. The input end is the point source location, and the output end is the rendered LF image, namely, PSF. Specially, a projection method is incorporated into the imaging model, eliminating the huge memory overhead induced by a large array of periodic elements. Taking captured PSF images as the ground truth, the LF camera is calibrated with the genetic algorithm initially and then the gradient-based optimization. This method is promising to be used in various LF camera applications, especially in challenging imaging conditions with severe aberrations.

[Effects of manipulating lactate dehydrogenase gene on metabolism of HEK-293 and production of human adenovirus].

Reducing lactate accumulation has always been a goal of the mammalian cell biotechnology industry. When animal cells are cultured in vitro, the accumulation of lactate is mainly the combined result of two metabolic pathways. On one hand, glucose generates lactate under the function of lactate dehydrogenase A (LDHA); on the other hand, lactate can be oxidized to pyruvate by LDHB or LDHC and re-enter the TCA cycle. This study comprehensively evaluated the effects of LDH manipulation on the growth, metabolism and human adenovirus (HAdV) production of human embryonic kidney 293 (HEK-293) cells, providing a theoretical basis for engineering the lactate metabolism in mammalian cells. By knocking out ldha gene and overexpression of ldhb and ldhc genes, the metabolic efficiency of HEK-293 cells was effectively improved, and HAdV production was significantly increased. Compared with the control cell, LDH manipulation promoted cell growth, reduced the accumulation of lactate and ammonia, significantly enhanced the efficiency of substrate and energy metabolism of cells, and significantly increased the HAdV production capacity of HEK-293 cells. Among these LDH manipulation measures, ldhc gene overexpression performed the best, with the maximum cell density increased by about 38.7%. The yield of lactate to glucose and ammonia to glutamine decreased by 33.8% and 63.3%, respectively; and HAdV titer increased by at least 16 times. In addition, the ATP production rate, ATP/O2 ratio, ATP/ADP ratio and NADH content of the modified cell lines were increased to varying degrees, and the energy metabolic efficiency was significantly improved.

Regulation of the pyruvate metabolism node by monogene and polygene engineering of HEK-293 cells.

HEK-293 cells are increasingly being used in the production of human adenovirus (HAdV) vaccines. However, the production of HAdV vaccine has not met the requirements of industrial production. Recently, we investigated the effects of various regulatory genes of the pyruvate metabolism node on the substance and energy metabolism and adenovirus reproduction in HEK-293 cells. Initially, single regulatory genes, including pkm2, pdhα, pyc2, mpc3, aralar1, ldha and pdk1, were studied. We found that metabolic performance and adenovirus reproduction capacity in HEK-293 cells were improved, and maximum adenovirus titre was increased approximately 15-fold. Next, we co-overexpressed the key genes, including pkm2, pyc2 and aralar1. The PYC2-A-P-L cells that had the appropriate co-overexpression levels of three genes had the most pronounced regulatory effect. The maximum cell density and maximum specific growth rate were increased by 21% compared with that in the control. The ΔLac/ΔGlc and ΔNH3/ΔGln were decreased by 26% and 27%, respectively. The ATP production rate and the ATP/O2 ratio were increased by 110% and 20%, respectively. The level of reactive oxygen species (ROS) was reduced by 60%. The adenovirus reproductive ability of the PYC2-A-P-L cells was approximately 30-fold higher than that of the control. The results showed that proper overexpression of the aralar1, pkm2 and pyc2 genes can significantly improve the substance and energy metabolism efficiency in HEK-293 cells, maximize the metabolic balance of pyruvate, and ultimately improve HAdV reproduction. This study provides a method of regulation of pyruvate metabolism and polygenic metabolic engineering in mammalian cells cultured in vitro and suggests an effective method for efficient HAdV production.

Anti-inflammatory effects of tilmicosin in a noninfectious mouse model of allergic asthma.

Tilmicosin, a semi-synthetic tylosin-derived macrolide antibiotic commonly used by veterinarians, has been shown to possess anti-inflammatory activity. However, possible use in asthma treatment has not yet been studied. In this study, we investigated the anti-inflammatory properties of tilmicosin using a murine asthma model. BALB/c mice were sensitized and challenged by intraperitoneal (i.p.) or nasal administration of ovalbumin. Tilmicosin (10 and 20 mg/kg) treatment resulted in a marked reduction in the presence of several types of immune cells and cytokines in the bronchoalveolar lavage fluids of mice. Levels of ovalbumin-specific Immunoglobulin E (IgE) were significantly decreased following treatment with tilmicosin (10 and 20 mg/kg). Histological studies using H&E (haematoxylin and eosin) and AB-PAS (alcian blue-periodic acid-Schiff) staining demonstrated that tilmicosin substantially inhibited both ovalbumin-induced inflammatory cells in lung tissues and goblet cell hyperplasia in the airway. These findings provided new insight into the immunopharmacological role of tilmicosin in terms of its effects in a murine model of asthma.

Anti-inflammatory effects of ivermectin in mouse model of allergic asthma.

BACKGROUND AND OBJECTIVE: Asthma is an inflammatory disease of the lungs that is characterised by increased inflammatory cell infiltration into the airways and poor respiratory function. Ivermectin is a semi-synthetic derivative of a family of macrocyclic lactones that shows broad-spectrum anti-parasitic activity. This drug has been shown to possess anti-inflammatory activity, but whether it can be used in asthma treatment has not yet been investigated. In this study, we aimed to investigate the inhibitory effects of ivermectin on allergic asthma symptoms in mice. METHODS AND RESULTS: We used a mouse asthma model, in which allergic airway inflammation and airway remodelling were induced by ovalbumin (OVA) sensitisation and challenge. Ivermectin or PBS treatment was administered 1 h before OVA challenge. Ivermectin at 2 mg/kg significantly diminished recruitment of immune cells, production of cytokines in the bronchoalveolar lavage fluids and secretion of OVA-specific IgE and IgG1 in the serum. Histological studies indicated that ivermectin suppressed mucus hypersecretion by goblet cells in the airway. CONCLUSIONS: This is the first study to demonstrate that ivermectin is an effective suppressor of inflammation and may be efficacious in the treatment of non-infectious airway inflammatory diseases such as allergic asthma.

Oxytetracycline attenuates allergic airway inflammation in mice via inhibition of the NF-κB pathway.

Oxytetracycline has been used in the treatment of acute and chronic bronchial inflammation and infectious asthma. However, its potential use for non-infectious asthma has not yet been studied. The objective of this study was to investigate the anti-inflammatory properties of oxytetracycline using a mouse asthma model. Female BALB/c mice, sensitized and challenged with ovalbumin. Naive CD4+ T cells from spleen were stimulated for 72 h with anti-CD3 (5 µg/ml) plus anti-CD28 (2.5 µg/ml) and differentiated into Th2 cells. IL-4, IL-5, IL-9, IL-13, and ovalbumin (OVA)-specific IgE production were measured by ELISA in BALF and cell supernatants. Histopathological evaluation was used to study the alterations in lung tissue. The mRNA levels of CCL5, CCL11, CCR1, and CCR3 were detected by real-time PCR. In addition, the protein levels of p-Akt, Akt, nuclear factor kappa B (NF-κB), IκBα and p-IκBα in lung tissue and cells were measured by western blot or immunofluorescence analysis. Oxytetracycline treatment caused a marked reduction in IL-4, IL-5, IL-13, immune cells, and the level of ovalbumin-specific IgE. Real-time PCR studies demonstrated that oxytetracycline can significantly reduce CCL5, CCL11 and their specific receptor CCR1 and CCR3. Histological studies demonstrated that oxytetracycline substantially inhibited ovalbumin-induced inflammatory cell infiltration in lung tissue and goblet cell hyperplasia in airway. Oxytetracycline inhibited the NF-κB activation via phosphorylation and degradation of IκBα both in vivo and in vitro. Furthermore, the increased phosphorylated Akt but not Akt protein levels in lung tissues after OVA inhalation were significantly reduced by the oral administration of oxytetracycline. These findings demonstrate an anti-inflammatory effect of oxytetracycline that might be mediated via reduction of inflammatory mediators and activation of transcription factors.