Role of site-directed mutagenesis and adjuvants in the stability and potency of anthrax protective antigen

Anthrax is a zoonotic infection caused by the gram-positive, aerobic, spore-forming bacterium Bacillus anthracis. Depending on the origin of the infection, serious health problems or mortality is possible. The virulence of B. anthracis is reliant on three pathogenic factors, which are secreted upon infection: protective antigen (PA), lethal factor (LF), and edema factor (EF). Systemic illness results from LF and EF entering cells through the formation of a complex with the heptameric form of PA, bound to the membrane of infected cells through its receptor. The currently available anthrax vaccines have multiple drawbacks, and recombinant PA is considered a promising second-generation vaccine candidate. However, the inherent chemical instability of PA through Asn deamidation at multiple sites prevents its use after long-term storage owing to loss of potency. Moreover, there is a distinct possibility of B. anthracis being used as a bioweapon; thus, the developed vaccine should remain efficacious and stable over the long-term. Second-generation anthrax vaccines with appropriate adjuvant formulations for enhanced immunogenicity and safety are desired. In this article, using protein engineering approaches, we have reviewed the stabilization of anthrax vaccine candidates that are currently licensed or under preclinical and clinical trials. We have also proposed a formulation to enhance recombinant PA vaccine potency via adjuvant formulation.     

Tumor-associated Macrophage-derived Interleukin-23 Interlinks Kidney Cancer Glutamine Addiction with Immune Evasion

Background

Glutamine addiction is a hallmark of clear cell renal cell carcinoma (ccRCC); yet whether glutamine metabolism impacts local immune surveillance is unclear. This knowledge may yield novel immunotherapeutic opportunities.

Neurochemistry of hyponatremic encephalopathy evaluated by MR spectroscopy

MR spectroscopy in a patient with hyponatremic encephalopathy due to the syndrome of inappropriate secretion of antidiuretic hormone revealed decreased N-acetyl-aspartate, creatine plus phosphocreatine, choline-containing compounds, and myo-inositol, with normal glutamate and increased glutamine, which normalized after Na normalization. The decreased concentrations of creatine plus phosphocreatine, choline-containing compounds and myo-inositol are explained by their release as osmolytes from brain cells to adapt to hypo-osmolality induced cerebral edema. Increased glutamine, which not only acts as an osmolyte but also protects neurons under excitotoxic conditions, may suggest that a disrupted glutamate-glutamine cycle may play an important role in the pathogenesis of hyponatremic encephalopathy.     

虫草素联合谷氨酰胺对LPS诱导的脓毒症大鼠炎症失衡及肝肺病理变化的影响

目的　研究虫草素（cordycepin,Cop）联合谷氨酰胺（glutamine,Gln）对脂多糖（lipopolysaccharides,LPS）诱导的脓毒症大鼠炎症失衡和肝肺病理变化的影响及其可能机制。 方法　将大鼠按体重随机分为5组：对照组、模型组（LPS组）、LPS+Cop组、LPS+Gln组和LPS+Cop+Gln组,腹腔注射LPS（5 mg/kg）诱导建立脓毒症大鼠模型。ELISA检测外周血中炎症因子IL-6、TNF-α、IL-1β和IL-10的含量;HE染色观察肝肺组织的病理损伤情况;TUNEL染色观察肝肺组织的细胞凋亡情况;Western blot检测肝肺组织中Caspase-3表达水平及NF-κB p65的磷酸化情况 。 结果　LPS+Cop组、LPS+Gln组和LPS+Cop+Gln组均能逆转LPS诱导的促炎因子（IL-6、TNF-α、IL-1β）的高表达和抗炎因子（IL-10）的低表达（P<0.05）,减轻病理损伤,抑制细胞凋亡（P<0.05）,降低凋亡蛋白Caspase-3高表达（P<0.05）,下调NF-κB p65的磷酸化水平（P<0.05）。 结论　在LPS诱导的脓毒症大鼠模型中,虫草素联合谷氨酰胺能有效改善其炎症失衡和肝肺病理变化。     

大剂量乌司他丁联合谷氨酰胺治疗对早期重度烧伤患者临床疗效、TNF-α及PaO2的影响

目的 分析大剂量乌司他丁联合谷氨酰胺治疗对早期重度烧伤患者临床疗效、肿瘤坏死因子-α（TNF-α）及动脉氧分压(PaO2)的影响。方法 选取我院2018年7月~2019年12月收治的重度烧伤患者85例,根据纳入排除标准,共选取83例患者作为研究对象,根据治疗方式的差异分为研究组（大剂量乌司他丁联合谷氨酰胺治疗）43例和对照组（常规剂量、乌司他丁联合谷氨酰胺治疗）40例。比较两组临床疗效,对比两组治疗前、治疗3d及12d后炎症因子水平、呼吸功能含量,并观察两组不良反应发生情况。结果 研究组总有效率（97.67%）高于对照组（82.50%）（P＜0.05）。治疗后3d 研究组IL-6、IL-8及TNF-α均较治疗前上升,但于治疗12d后达到最低值;同时,治疗后任意时间点研究组IL-6、IL-8及TNF-α均低于对照组（P＜0.05）。治疗前,2组呼吸功能各指标比较无差异(P＞0.05),治疗后3d 研究组呼吸频率较治疗前降低,PaO2及PaO2/FiO2均较治疗前上升,且治疗12d后达到最低值（峰值）;同时,治疗后任意时间点研究组呼吸频率均低于对照组,PaO2及PaO2/FiO2均高于对照组（P＜0.05）。两组治疗前IgA、IgG和IgM水平比较无差异,治疗3d后各组IgA、IgG和IgM水平较治疗前显著降低,并于12d升高达到峰值,同时研究组在治疗后各时间点IgA、IgG和IgM水平均高于对照组（P＜0.05）。联合组并发症发生率（6.98%）与对照组（2.50%）比较无差异(P＞0.05)。结论 大剂量乌司他丁联合谷氨酰胺治疗可改善早期重度烧伤患者体内炎症反应及呼吸功能,提高其免疫功能,疗效佳、安全性高,可在临床推广应用。     

Amino acid signatures in the developing mouse retina

This study characterizes the developmental patterns of seven key amino acids: glutamate, γ-amino-butyric acid (GABA), glycine, glutamine, aspartate, alanine and taurine in the mouse retina. We analyze amino acids in specific bipolar, amacrine and ganglion cell sub-populations (i.e. GABAergic vs. glycinergic amacrine cells) and anatomically distinct regions of photoreceptors and Müller cells (i.e. cell bodies vs. endfeet) by extracting data from previously described pattern recognition analysis. Pattern recognition statistically classifies all cells in the retina based on their neurochemical profile and surpasses the previous limitations of anatomical and morphological identification of cells in the immature retina. We found that the GABA and glycine cellular content reached adult-like levels in most neurons before glutamate. The metabolic amino acids glutamine, aspartate and alanine also reached maturity in most retinal cells before eye opening. When the overall amino acid profiles were considered for each cell group, ganglion cells and GABAergic amacrine cells matured first, followed by glycinergic amacrine cells and finally bipolar cells. Photoreceptor cell bodies reached adult-like amino acid profiles at P7 whilst Müller cells acquired typical amino acid profiles in their cell bodies at P7 and in their endfeet by P14. We further compared the amino acid profiles of the C57Bl/6J mouse with the transgenic X-inactivation mouse carrying the lacZ gene on the X chromosome and validated this animal model for the study of normal retinal development. This study provides valuable insight into normal retinal neurochemical maturation and metabolism and benchmark amino acid values for comparison with retinal disease, particularly those which occur during development.     

Glutamine downregulates TLR-2 and TLR-4 expression and protects intestinal tract in preterm neonatal rats with necrotizing enterocolitis

Background/Purpose

Toll-like receptor (TLR)-4 and TLR-2 play an essential role in the pathogenesis of necrotizing enterocolitis (NEC). In this study, we investigated the protective effect of glutamine (Gln) in an NEC neonatal rat model, and the potential association with TLR-4 and TLR-2 expression in local intestinal tissues.

Methods

Preterm neonatal rats were randomly divided into 3 groups: normal control; NEC model; and NEC plus Gln intervention. NEC was induced by feeding with artificial milk substitutes, plus exposure to hypoxia and cold stress. All preterm rats were sacrificed at 3 days after birth. The intestinal tissues were taken for pathological analysis. Protein and mRNA expression of TLR-2, TLR-4, and caspase-3 was examined by immunohistochemistry and real-time RT-PCR, respectively.

Results

Compared with the normal control, the NEC neonatal rats showed mucosal injury and upregulated mRNA and protein expression of TLR-2, TLR-4, and caspase-3 in ileum and colon. Gln intervention significantly reduced the mucosal injury and suppressed the upregulated expression of TLR-2, TLR-4, and caspace-3 in the ileum and colon of NEC neonatal rats.

Conclusions

Gln protects the intestinal tract of NEC neonatal rats, which may be associated with the reduction of TLR-2 and TLR-4 expression in intestines     

Effects of glutamine on wound healing

Studies reporting the need for replacing amino acids such as glutamine (Gln), hydroxymethyl butyrate (HMB) and arginine (Arg) to accelerate wound healing are available in the literature. The primary objective of this study was to present the effects of Gln on tissue hydroxyproline (OHP) levels in wound healing. This study was conducted on 30 female Sprague Dawley rats with a mean weight of 230 ± 20 g. Secondary wounds were formed by excising 2 × 1 cm skin subcutaneous tissue on the back of the rats. The rats were divided into three equal groups. Group C (Control): the group received 1 ml/day isotonic solution by gastric gavage after secondary wound was formed. Group A (Abound): the group received 0·3 g/kg/day/ml Gln, 0·052 g/kg/day/ml HMB and 0·3 g/kg/day/ml Arg by gastric gavage after secondary wound was formed. Group R (Resource): the group received 0·3 g/kg/day/ml Gln by gastric gavage after secondary wound was formed. The OHP levels of the tissues obtained from the upper half region on the 8th day and the lower half region on the 21st day from the same rats in the groups were examined. Statistical analysis was performed using the statistics program SPSS version 17.0. No statistically significant differences were reported with regard to the OHP measurements on the 8th and 21st days (8th day: F = 0·068, P = 0·935 > 0·05; 21st day: F = 0·018, P = 0·983 > 0·05). The increase in mean OHP levels on the 8th and 21st days within each group was found to be statistically significant (F = 1146·34, P = 0·000 < 0·001). We conclude that in adults who eat healthy food, who do not have any factor that can affect wound healing negatively and who do not have large tissue loss at critical level, Gln, Arg and HMB support would not be required to accelerate secondary wound healing.