Glycosylation of bacterial antigens changes epitope patterns

Introduction

Unlike glycosylation of proteins expressed in mammalian systems, bacterial glycosylation is often neglected in the development of recombinant vaccines.

Methods

Here, we compared the effects of glycosylation of YghJ, an Escherichia coli protein important for mucus attachment of bacteria causing in urinary tract infections (UTIs). A novel method based on statistical evaluation of phage display for the identification and comparison of epitopes and mimotopes of anti-YghJ antibodies in the sera was used. This is the first time that the effect of glycosylation of a recombinant bacterial antigen has been studied at the peptide epitope level.

Results

The study identifies differences in the immune response for (non)-glycosylated antigens in rabbits and pigs and compares them to a large group of patients with UTI, which have been diagnosed as positive for various bacterial pathogens. We identified glycosylation-specific peptide epitopes, a large immunological similarity between different UTI pathogens, and a broad peptide epitope pattern in patients and animals, which could result in a variable response in patients upon vaccination.

Discussion

This epitope analysis indicates that the vaccination of rabbits and pigs raises antibodies that translate well into the human immune system. This study underlines the importance of glycosylation in bacterial vaccines and provides detailed immune diagnostic methods to understand individual immune responses to vaccines.

Detection of Antibodies against Endemic and SARS-CoV-2 Coronaviruses with Short Peptide Epitopes

(1) Background: Coronavirus proteins are quite conserved amongst endemic strains (eCoV) and SARS-CoV-2. We aimed to evaluate whether peptide epitopes might serve as useful diagnostic biomarkers to stratify previous infections and COVID-19. (2) Methods: Peptide epitopes were identified at an amino acid resolution that applied a novel statistical approach to generate data sets of potential antibody binding peptides. (3) Results: Data sets from more than 120 COVID-19 or eCoV-infected patients, as well as vaccinated persons, have been used to generate data sets that have been used to search in silico for potential epitopes in proteins of SARS-CoV-2 and eCoV. Peptide epitopes were validated with >300 serum samples in synthetic peptide micro arrays and epitopes specific for different viruses, in addition to the identified cross reactive epitopes. (4) Conclusions: Most patients develop antibodies against non-structural proteins, which are useful general markers for recent infections. However, there are differences in the epitope patterns of COVID-19, and eCoV, and the S-protein vaccine, which can only be explained by a high degree of cross-reactivity between the viruses, a pre-existing immune response against some epitopes, and even an alternate processing of the vaccine proteins.

Lipopolysaccharide-induced murine lung injury results in long-term pulmonary changes and downregulation of angiogenic pathways

Acute respiratory distress syndrome is the most severe form of acute lung injury (ALI) and is associated with significant mortality. Lipopolysaccharide (LPS)-induced injury is a valuable murine model of ALI but there is a paucity of data on lung regeneration and the role of angiogenic signaling involving vascular endothelial growth factor (VEGF). Eight-week-old male C57BL/6J mice were randomized to receive intratracheal instillation of either LPS or isovolumetric phosphate buffered saline as a vehicle control. Mice were observed at a single follow-up time-point that was either short-term (24 h or 4 days) or long-term (7 days or 4 weeks). On pulmonary function testing, LPS-treated mice had increased compliance at 4 weeks post-instillation, which correlated with decreased vascularization and with time-dependent, progressive decrease in alveolarization. Treadmill exercise tolerance testing demonstrated impaired performance at 24 h, 4 days and 4 weeks following LPS exposure. On lung protein analysis, LPS instillation decreased VEGF expression at up to 4 weeks, and decreased activation of its key receptor, VEGFR2 at 7 days and 4 weeks post-instillation. Together, these data provide insight on long-term pulmonary functional outcomes 4 weeks after ALI and identify angiogenic proteins as possible therapeutic targets following lung injury.

An in-line digestive cartridge increases enteral fat and vitamin absorption in a porcine model of short bowel syndrome

BACKGROUND & AIMS

Short bowel syndrome (SBS) occurs after intestinal loss resulting in parenteral nutrition dependence and micronutrient deficiencies, which may lead to life-limiting complications. ALC-078 is a cartridge containing immobilized lipase that connects in-line with enteral feeding sets and digests fats in enteral nutrition (EN). In this study, we evaluate the efficacy of ALC-078 to improve fat and nutrient absorption in a porcine SBS model.

METHODS

Fifteen male Yorkshire piglets were assessed. Animals were randomized to no intestinal resection (n = 5), 75% resection (n = 5), or 75% resection + ALC-078 (n = 5). After recovery, animals were treated for 14 days. Piglets received 60% of nutrition from continuous EN and 40% from chow. The degree of fat malabsorption was determined by the coefficient of fat absorption (CFA) following a 72-h stool collection. Body weight, fat-soluble vitamins, and nutritional markers were assessed.

RESULTS

Adverse events were similar across the three groups (P = 1.00). ALC-078-treated animals had similar weight gain compared to resected piglets. Resected animals had a lower CFA compared to unresected controls (79.3% vs. 95.2%, P = 0.01) while there was no significant difference in the ALC-078 animals (87.1% vs. 95.2%, P = 0.19). Between Study Days 1 and 15, ALC-078 animals had increased concentrations of vitamin D (12.2 vs. 8.7 ng/mL, P = 0.0006), and vitamin E (4.3 vs. 2.5 mg/L, P = 0.03). These markers did not significantly change in untreated resected animals.

CONCLUSION

ALC-078 increases the absorption of fat-soluble vitamins and may improve fat malabsorption. Future studies should determine whether ALC-078 can reduce PN dependence and if these findings translate to human patients with SBS.

Mechanisms for the effects of fish oil lipid emulsions in the management of parenteral nutrition-associated liver disease

Parenteral nutrition (PN) can be life saving for infants unable to adequately absorb enteral nutrients due to intestinal failure from inadequate bowel length or function. However, long-term PN carries significant morbidity and mortality, with 30 to 60% of patients developing progressive liver dysfunction. The etiology of PN-associated liver disease (PNALD) is poorly understood, however the involvement of lipid emulsions in its pathogenesis has been clearly established, with new emphasis emerging on the role of omega-6 polyunsaturated fatty acids and omega-3 polyunsaturated fatty acids. Recent studies evaluating the use of parenteral fish oil lipid emulsions instead of soybean oil lipid emulsions have demonstrated marked improvements in cholestasis, morbidity, and mortality in patients with PNALD treated with fish oil. This review provides an overview of the role of lipid emulsions in the pathogenesis of PNALD and the proposed mechanisms by which parenteral fish oil lipid emulsions may be exerting their beneficial effects.

Systematic review and meta-analysis of steatosis as a risk factor in major hepatic resection

Background

The risk of major hepatic resection in patients with hepatic steatosis remains controversial. A meta-analysis was performed to establish the best estimate of the impact of steatosis on patient outcome following major hepatic surgery.

Methods

A systematic search was performed following Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines. Risk ratios (RRs) for complication and mortality rates were calculated for patients with no, less than 30 per cent and at least 30 per cent steatosis, and a meta-analysis was carried out.

Results

Of six observational studies identified, four including a total of 1000 patients were subjected to meta-analysis; two others were tabulated separately. Compared with patients without steatosis, those with less than 30 per cent and at least 30 per cent steatosis had a significantly increased risk of postoperative complications, with a RR of 1·53 (95 per cent confidence interval (c.i.) 1·27 to 1·85) and 2·01 (1·66 to 2·44) respectively. Patients with at least 30 per cent steatosis had an increased risk of postoperative death (RR 2·79, 95 per cent c.i. 1·19 to 6·51).

Conclusion

Patients with steatosis had an up to twofold increased risk of postoperative complications, and those with excessive steatosis had an almost threefold increased risk of death.

Fish oil prevents essential fatty acid deficiency and enhances growth: clinical and biochemical implications

Fish oil, a rich source of omega-3 fatty acids, has never been used as the sole source of lipid in clinical practice for fear of development of essential fatty acid deficiency, as it lacks the believed requisite levels of linoleic acid, an omega-6 fatty acid. The objectives of this study were to establish biochemical standards for fish oil as the sole fat and to test the hypothesis that fish oil contains adequate amounts of omega-6 fatty acids to prevent essential fatty acid deficiency. Forty mice were divided into 2 groups that were either pair fed or allowed to eat ad libitum. In each group, 4 subgroups of 5 mice were fed 1%, 5%, and 10% fish oil diets by weight or a control soybean diet for 9 weeks. Blood was collected at 4 time points, and fatty acid analysis was performed. Food intake and weight status were monitored. All groups but the pair-fed 1% fish oil group gained weight, and the 5% fish oil group showed the highest caloric efficiency in both pair-fed and ad libitum groups. Fatty acid profiles for the 1% fish oil group displayed clear essential fatty acid deficiency, 5% fish oil appeared marginal, and 10% and soybean oil diets were found to prevent essential fatty acid deficiency. Fish oil enhances growth through higher caloric efficiency. We established a total omega-6 fatty acid requirement of between 0.30% and 0.56% of dietary energy, approximately half of the conventionally believed 1% as linoleic acid. This can presumably be attributed to the fact that fish oil contains not only a small amount of linoleic acid, but also arachidonic acid, which has greater efficiency to meet omega-6 fatty acid requirements.

Glutathione conjugates recognize the Rossmann fold of glyceraldehyde-3-phosphate dehydrogenase

Leukotriene (LT) C4 and other glutathione conjugates are synthesized intracellularly and then move to the plasma membrane for export. The intracellular proteins that bind these molecules and the significance of these interactions are poorly understood. To identify the binding sites of membrane-associated proteins that recognize these molecules, we utilized photoaffinity probes to label the inner leaflet of erythrocytes. The predominant molecule labeled with S-(p-nitrobenzyl)glutathione-[125I]4-azidosalicylic acid (PNBG-[125I]ASA) or LTC4-[125I]4-azidosalicylic acid (LTC4-[125I]ASA) was 38 kDa. The protein was labeled with PNBG-[125I]ASA, electroblotted to polyvinylidene difluoride membranes, digested in situ with lysyl endopeptidase, and two radiolabeled peptides isolated by reverse phase-high performance liquid chromatography. These contained an identity of 7/11 with amino acids 119-129, and 11/11 with amino acids 67-77 of human liver glyceraldehyde-3-phosphate dehydrogenase (GAPDH), respectively. Photoaffinity labeling with PNBG-[125I]ASA was blocked completely by 100 microM ATP and greater than 50% with 100 microM NAD+. LTC4-[125I]ASA binding to the NAD+ site was confirmed by V8 protease digestion of purified GAPDH labeled with LTC4-[125I]ASA or PNBG-[125I]ASA, with both labels localized to the 6.8-kDa N-terminal fragment. Photoaffinity labeling of HL-60 cells with LTC4-125I-ASA identified GAPDH as the predominant cytoplasmic binding protein in these cells. These data indicate that GAPDH is a membrane-associated and cytoplasmic protein which binds glutathione conjugates including LTC4.

Ubiquitin fusion proteins are overexpressed in colon cancer but not in gastric cancer

A cDNA clone (AF3) encoding the ubiquitin A gene 52 amino acid extension fusion protein (UbA52) was isolated from a subtracted cDNA library of human colorectal carcinoma minus adjacent normal mucosa. In Northern hybridization the mRNA signal for UbA52 was greater in surgical samples of colonic carcinoma (T) than in paired adjacent normal (N) tissues in 24 of 29 cases (T/N = 3.4 +/- 0.5, P < 0.01). An oligonucleotide probe specific for only the 52 amino acid extension confirmed the overexpression of UbA52. In contrast, there was no overexpression of UbA52 mRNA in gastric cancer samples (n = 7, T/N = 1.0 +/- 0.3). The mRNA of several ribosomal proteins, and of another ubiquitin A gene fusion protein, UbA80, with an 80 amino acid extension of ribosomal protein S27a, have been reported to be over-expressed in colon cancer, but not as yet at the protein level. Using rabbit antisera to the ribosomal protein component S27a we demonstrate over-expression of S27a at the protein level in colonic (n = 5), but not gastric (n = 6) carcinomas. Therefore it is likely that both UbA80 and UbA52 are overexpressed in colon cancer, but not in gastric cancer.

Human ribosomal protein L37 has motifs predicting serine/threonine phosphorylation and a zinc-finger domain

Ribosomal protein L37 mRNA is overexpressed in colon cancer. The nucleotide sequences of human L37 from several tumor and normal, colon and liver cDNA sources were determined to be identical. L37 mRNA was approximately 375 nucleotides long encoding 97 amino acids with M(r) = 11,070, pI = 12.6, multiple potential serine/threonine phosphorylation sites and a zinc-finger domain. The human sequence is compared to other species.

Nucleotide and deduced amino acid sequence of human ribosomal protein L18

Ribosomal protein L18 mRNA is overexpressed in human colorectal cancer compared to normal colon tissue. We report the nucleotide sequence of human L18 cDNA derived from a normal colon source. There were no mutational changes in segments of L18 cDNA derived from two tumor sources. The L18 cDNA was 690 base pairs long and predicts a single open reading frame of 564 nucleotides, encoding 188 amino acids with a M(r) = 21,621, it is homologous to rat L18 and Xenopus laevis L14.

Gastric and hepatocellular carcinomas do not overexpress the same ribosomal protein messenger RNAs as colonic carcinoma

The levels of a number of ribosomal protein mRNAs are reported to be increased in human colon cancer. We have assessed whether selected ribosomal protein mRNAs are overexpressed in other gastrointestinal malignancies, namely gastric and hepatocellular carcinomas. Subtracted complementary DNA libraries were generated from paired samples of human (a) colorectal carcinoma minus adjacent normal colonic mucosa and (b) hepatocellular carcinoma minus adjacent normal liver. Screening of approximately 3% of these library clones determined that ribosomal protein mRNAs encoding L18 and L37 (not previously reported) and P0 and S6 were overexpressed in one or the other library. Their complementary DNA inserts were then used as probes to evaluate their expression in a larger number of paired tumor/normal surgical samples of human colonic, gastric, and hepatocellular carcinomas, by Northern hybridization. The mRNA signal was greater in the colonic carcinoma than in paired adjacent normal colonic mucosa in 38 of 42 cases for P0 [tumor/normal (T/N) ratio = 3.0 +/- 0.3, mean +/- SE, P < 0.001] (G. F. Barnard, R. J. Staniunas, S. Bao, K. Mafune, J. L. Gollan, G. D. Steele, Jr., and L. B. Chen, Cancer Res., 52: 3067-3072, 1992), in 25 of 28 cases for L18 (T/N ratio = 3.7 +/- 0.5, P < 0.001), in 27 of 28 cases for L37 (T/N ratio = 5.3 +/- 0.4, P < 0.001), and in 24 of 28 cases for S6 (T/N ratio = 3.1 +/- 0.5, P < 0.01). The level of mRNA overexpression of L18 and S6 did not correlate with the Dukes' stage of disease. In hepatocellular carcinoma samples, using the same four ribosomal protein complementary DNA probes, only P0 mRNA was significantly increased (T/N ratio = 2.8 +/- 0.4, n = 6, P = 0.047). In gastric carcinoma samples, none of these mRNAs was increased (mean T/N ratios = 0.9-1.2, n = 6). Therefore, gastric and hepatocellular carcinomas do not overexpress the same ribosomal protein mRNAs as do colonic carcinoma.

The effect of delta 1tetrahydrocannabinol on luteinizing hormone release in castrated and hypothalamic deafferented male rats

delta 1Tetrahydrocannabinol (THC) acutely suppresses tonic serum luteinizing hormone (LH) and prolactin levels in adult male rats. The exact site of its action has not been identified. We have performed complete hypothalamic deafferentation (CHD), which disrupts the medial basal hypothalamus (MBH) from the rest of the CNS, but did not abolish the ability of THC to suppress hypothalamic-pituitary responses in gonadectomized male rats. This was shown by the equal reduction in serum levels of LH and prolactin in non-deafferented (ND) and CHD animals. These results indicate that THC is able to act inside the MBH and that the MBH-pituitary axis remains responsive to its inhibitory effect despite interruption of the neural connections between the MBH and extrahypothalamic areas. However, the corticotropin releasing factor neurons in the MBH appear functionally impaired as a result of the transection and become unresponsive to the normally produced THC stimulation. Different patterns of action seem to govern the various hypophyseal hormones controlled by the hypothalamus, suggesting that the release of LH releasing hormone and prolactin inhibiting factor might be maintained by the activity of neurons surviving inside the island.

Corticotrophin and corticosterone secretion following delta 1-Tetrahydrocannabinol, in intact and in hypothalamic deafferentated male rats

Adult male rats, either intact (N) or bearing complete hypothalamic deafferentations (CHD), were injected with delta 1-tetrahydrocannabinol (THC: 5 mg/kg BW, IP). Forty-five minutes later, they were decapitated and trunk blood was collected for serum ACTH and corticosterone (CS) determinations. In the N animals, serum levels of both ACTH and CS were markedly elevated in the drug-treated, as compared to the vehicle-treated group (approximately 8-fold and 10-fold, respectively). In CHD rats, on the contrary, THC administration did not significantly alter serum concentrations of either ACTH or CS. These results demonstrate (1) that acute treatment with THC stimulates the secretion of ACTH as well as of CS; and (2) that extrahypothalamic sites and/or neural pathways mediate this effect.

Changes in rodent thyroid hormones and cyclic-AMP following treatment with pineal indolic compounds

Treatment of rats with pineal indolic compounds 5-methoxytryptophol, 5-hydroxytryptophol and serotonin brought about a significant increase in serum thyroxine levels, while serotonin and melatonin caused an increase in thyroid cAMP content with corresponding decrease in the gland's hormones. The total quantity of cAMP in the thyroid was also increased by melatonin in the organ culture system. All these findings would indicate that some of the pineal indoleamines elicit a direct action on the thyroid by stimulating the adenyl cyclase activity and intrathyroidal cAMP, bringing about increased release of thyroxine into the blood stream, and that this is usually not accompanied by adequate synthesis in the gland. Our observation that continuous darkness, which stimulates pineal activity, also brought about an increase in cAMP, concours with our finding of a stimulatory effect of the indolic compounds on thyroid hormone release.

Acute effect of delta1-tetrahydrocannabinol on the hypothalamo-pituitary-ovarian axis in the rat

Administration of delta1-tetrahydrocannabinol (delta1-THC), the principal psychoactive ingredient of cannabis, to proestrous rats (2 mg/rat, i.p., between 12.00 and 16.00 h) suppressed the proestrous rise in the plasma levels of LH, FSH and prolactin (Prl) and caused a 24 h delay in ovulation. Furthermore, the increased accumulation of prostaglandins of the E-type (PGE) in the ovaries, normally seen on the evening of proestrus, was prevented. Earlier (08.00-10.30 h) or later (18.00 h) administration of the drug on the day of proestrus was only partially effective in inhibiting ovulation. The suppressive effects of delta1-THC on ovulation and gonadotropin secretion were prevented by administration of gonadetropin releasing hormone (GnRH, 0.2 microgram/rat) 1 h after the drug, indicating that the central action of delta1-THC was exerted on the hypothalamus and not on the pituitary gland. Administration of ovine luteinizing hormore (oLH, 2.5 microgram/rat at 16.30 h on the day of proestrus restored ovulation and ovarian PGE accumulation in Nembutal-treated rats, but not in delta1-THC-treated rats; higher doses of oLH (5-10 microgram/rat) reversed the action of delta1-THC on these two parameters.