The oxidative stress hypothesis of atherosclerosis: cause or product?

The oxidative stress hypothesis postulates that endogenous free radicals of unknown origin, possibly derived from mural cells, oxidize low density lipoproteins and that oxidation products are allegedly responsible for initiation and progression of atherosclerosis. The thesis fails to explain its topography, site specific severity and the iatrogenic and experimental hemodynamic induction of atherosclerosis under conditions complying with the logic of Koch's postulates. Free radicals are generated by biomechanical scission of macromolecules and polymers, the biophysical mechanism underlying bioengineering fatigue in atherogenesis with oxidative damage a secondary, contributory factor to mural pathology. The plentiful supply of antioxidants negates oxidative stress as the dominant factor in atherogenesis.     

The tripartite capsid gene of Salmonella phage Gifsy-2 yields a capsid assembly pathway engaging features from HK97 and λ

Phage Gifsy-2, a lambdoid phage infecting Salmonella, has an unusually large composite gene coding for its major capsid protein (mcp) at the C-terminal end, a ClpP-like protease at the N-terminus, and a ∼ 200 residue central domain of unknown function but which may have a scaffolding role. This combination of functions on a single coding region is more extensive than those observed in other phages such as HK97 (scaffold-capsid fusion) and λ (protease-scaffold fusion). To study the structural phenotype of the unique Gifsy-2 capsid gene, we have purified Gifsy-2 particles and visualized capsids and procapsids by cryoelectron microscopy, determining structures to resolutions up to 12 Å. The capsids have lambdoid T = 7 geometry and are well modeled with the atomic structures of HK97 mcp and phage λ gpD decoration protein. Thus, the unique Gifsy-2 capsid protein gene yields a capsid maturation pathway engaging features from both phages HK97 and λ.     

Use of λgt11 and monoclonal antibodies to map the gene for the 60,000 dalton glycoprotein of infectious laryngotracheitis virus

To localize the gene encoding the 60 kD glycoprotein (gp60) of infectious laryngotracheitis virus (ILTV), a library of the ILTV genome was constructed in the gt11 expression vector. Twelve recombinant bacteriophages expressing gp60 epitopes as fusion products with -galactosidase were detected by immunoscreening with monoclonal antibodies specific for gp60. The ILTV DNA sequence contained in one of these recombinants 24-4 was used as a hybridization probe for mapping the insert sequence on the viral genome. The gene for the gp60 was located at map unit 0.72–0.77 in the unique long region (U_L) of the ILTV genome. The DNA sequence of the 1.2 kb insert of 24-4 containing the gp60 epitope was determined. The majority of deduced gp60 amino acid sequence has no homology with any of the known alphaherpesvirus glycoproteins.The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession number X 121209.     

Aging and cardiovascular diseases: The role of gene–diet interactions

In the study of longevity, increasing importance is being placed on the concept of healthy aging rather than considering the total number of years lived. Although the concept of healthy lifespan needs to be defined better, we know that cardiovascular diseases (CVDs) are the main age-related diseases. Thus, controlling risk factors will contribute to reducing their incidence, leading to healthy lifespan. CVDs are complex diseases influenced by numerous genetic and environmental factors. Numerous gene variants that are associated with a greater or lesser risk of the different types of CVD and of intermediate phenotypes (i.e., hypercholesterolemia, hypertension, diabetes) have been successfully identified. However, despite the close link between aging and CVD, studies analyzing the genes related to human longevity have not obtained consistent results and there has been little coincidence in the genes identified in both fields. The APOE gene stands out as an exception, given that it has been identified as being relevant in CVD and longevity. This review analyzes the genomic and epigenomic factors that may contribute to this, ranging from identifying longevity genes in model organisms to the importance of gene–diet interactions (outstanding among which is the case of the TCF7L2 gene).     

Effects of sulphonylureas on cAMP-stimulated Cl− transport via the cystic fibrosis gene product in human epithelial cells

The cystic fibrosis gene product (CFTR) is a Cl^– channel that possesses specific binding sites for cytosolic adenosine triphosphate (ATP) and is activated by cyclic adenosine monophosphate (cAMP)-dependent protein kinases. We explored the possibility that CFTR shares a common pharmacology with another ATP-regulated channel protein, the ATP-sensitive K⁺ channel that is blocked by sulphonylureas and activated by diazoxide. cAMP-stimulated Cl^– effluxes were measured with ³⁶Cl^– in the epithelial cell line T84 which stably expresses CFTR. Neither glibenclamide (30 M), tolbutamide (1 mM) nor diazoxide (100 M) significantly affected forskolin-activated ³⁶Cl^– effluxes in T84 cells. In patch-clamp experiments, glibenclamide exerted only weak inhibitory effects on the whole-cell currents through CFTR with an IC₅₀ of around 0.1 mM. Tolbutamide at 1 mM, but not at 0.1 mM, blocked a current of small amplitude which reversed near the equilibrium potential for K⁺ ions. We conclude that sulphonylureas and diazoxide are not effective antagonists of endogenous CFTR Cl^– channels.     

The androgen receptor gene: A major modifier of speed of neuronal transmission and intelligence?

Humans show considerable additive genetic variance in cognitive ability or general intelligence (g) but the genes that influence this variation are largely unknown. It is suggested here that the X-linked androgen receptor gene (AR) has a major modifying effect on speed of neuronal transmission and thus on g. The AR is polymorphic in its N-terminal transactivation domain which encodes a polyglutamine tract (CAGn) with a parametric mean of n=21 CAG repeats and normal variation between n=11 and n=30 repeats . Very low repeat numbers are associated with mental retardation, repeat numbers above 30 with reduced cognitive function, and CAGn greater than 40 with spinal and bulbar muscular atrophy. Within the range of 11-30 repeats short CAG chains are associated with high androgen sensitivity and high sperm counts. Despite this, all human populations contain many individuals with n>21 repeats. I suggest that within the range of 11-30 repeats there is a positive association with speed of neuronal transmission and values of g. The advantage of high g and the consequent spread of alleles for high CAGn will be countered by the negative effects on sperm production. Below CAGn=11 and above CAGn=30 neuronal speed may reduce, thus leading to reductions in g and loss of function of neurons. In support of the model I discuss the link between the X-chromosome and g, the comparative structure of the AR gene in the primates, and the variation in CAGn and g in human ethnic groups.     

The β-tubulin-encoding gene from Microbotryum violaceum: unusual in a variety of ways

The beta-tubulin gene of Microbotryum violaceum was sought originally for its potential use in improving the transformation of this organism. The gene was cloned and its nucleotide sequence was determined. The gene was predicted to encode a 444-residue protein with strong sequence similarity to other beta-tubulins. The coding region was 2.85 kb, much larger than the corresponding genes from other organisms. This was due to the large number of introns in this gene, as determined by comparison of the cDNA sequence with that for the genomic clone. This gene contained 14 introns, which is the most introns in a beta-tubulin-encoding gene yet reported for any organism. Intron position comparisons between the M. violaceum gene and those from beta-tubulin genes of other organisms revealed a striking result, since 10 of the 14 introns were unique. An additional feature of the gene's organization was an unusually long 5' untranslated region, predicted to be nearly 1 kb in length. The possible significance of these unusual features of genetic structure is discussed.     

The P4pc: An electrophysiological marker of attentional disengagement?

The processing of successive targets requires that attention be engaged and disengaged. Whereas attentional engagement can be studied by means of the N2pc component of the event-related potential (ERP), no ERP component has been linked to attentional disengagement. Here, we report the finding of such a component using an RSVP paradigm with multiple, successive targets and with a spatial-cuing paradigm. In both experiments, disengagement of attention was necessary to attend to subsequent targets. A distinct waveform following the N2pc, which we call the P4pc (Positivity 400 ms post-target posterior contralateral), was found. The P4pc was found when a lateralized cue indicated that attention would be needed for the processing of a target at either the same or a different location as the cue, but not when only the cue was to be responded to, indicating that the need to disengage attention is a prerequisite for the P4pc to occur. We expect the P4pc to provide a valuable addition to the set of electrophysiological measures used to study the dynamics and mechanisms of visual attention and visual search.     

The candidate gene approach: have murine models informed the study of human SLE?

Genome wide linkage studies in human SLE have identified seven highly significant loci linked to SLE, and more than 20 other loci showing suggestive linkage to disease. However, pin-pointing the susceptibility alleles in candidate genes within these linkage regions is challenging, due the genetic heterogeneity, racial differences and environmental influences on disease aetiology. Utilization of murine models of spontaneous lupus nephritis provide a complementary approach, which may then identify candidate genes for analysis in human cases. This review highlights the utility of cross-species approach to identify and characterize the effect of given candidate genes in lupus. The examples described in this review demonstrate the importance of bringing together both genetic and functional information in human and mouse studies.     

Pío del Río-Hortega: The Revolution of Glia

Pío del Río-Hortega (Portillo, 1882–Buenos Aires 1945) was a Spanish pioneer scientist. Here, we highlight his professional merits and scientific qualities, facets that permitted him to open the eyes of the scientific community to the existence of microglia and oligodendroglia. Indeed, after Cajal formulated the “neuron doctrine” (1888), Río-Hortega was perhaps whose contributions represent the most important advances in our understanding of the microscopic anatomy of the nervous system. Río-Hortega achieved his discoveries thanks to a histological staining method developed by himself, the ammoniacal silver carbonate staining, absolutely fundamental for his histological studies. His early education in Histology was due to Professor Leopoldo López-García, at the Faculty of Medicine of Valladolid. Later in Madrid (1912), Santiago Ramón y Cajal and Nicolás Achúcarro became his definitive tutors. Achúcarro was an exceptional neurohistopathologist and authentic mentor for Río-Hortega until his death in 1918. The scientific career of Río-Hortega oscillated between the international recognition of his scientific discoveries (nominated for the Nobel Prize in 1928 and 1937), and the personal/social misfortunes he suffered in Spain, such as his expulsion from Cajal's Laboratory in 1920, the hostile envy of some conservative Spanish academics for his scientific merit (1934), and his sad political exile (Paris, Oxford, and Buenos Aires) due to the Spanish Civil War (1936–1939). Perhaps, Pío del Río-Hortega is the paradigm of a Spanish scientist of the beginning of XX^th century, living between the heaven and the hell, he revolutionized the scientific concept of glia. Anat Rec, 303:1232–1241, 2020. © 2019 American Association for Anatomy     

The β-tubulin gene of Epichloë typhina from perennial ryegrass (Lolium perenne)

Summary Epichloë typhina is a biotrophic fungal pathogen which causes choke disease of pooid grasses. The anamorphic state, Acremonium typhinum, is placed in the section Albo-lanosa along with related, mutualistic, seeddisseminated endophytes. As an initial study of gene structure and evolution in Epichloë and related endophytes, the -tubulin gene, tub2, of the perennial ryegrass choke pathogen (EtPRG) was cloned and sequenced. The coding sequence and the predicted -tubulin amino acid sequence were highly homologous to the Neurospora crassa homologs, and to one of the two -tubulin genes of Emericella nidulans. However, two introns characteristic of the N. crassa and Em. nidulans genes were absent in the E. typhina gene. Furthermore, one of the remaining introns possessed the uncommon 5 splice junction, GC. In contrast to published observations concerning other Ascomycetes, a mutant of EtPRG, selected for resistance to methyl-2-benzimidazole carbamate (benomyl), possessed no alteration of its -tubulin coding sequence.     

The role of glucocorticoid in SIRPα and SHP-1 gene expression in AIHA patients

The aim of this work was to evaluate the regulation of SIRPα, an inhibitory phagocyte receptor, and the phosphatase SHP-1 in monocytes of patients with autoimmune hemolytic anemia, and the role of dexamethasone on SIRPα and SHP-1 gene expression and erythrophagocytosis in vitro. SIRPα and SHP-1 expression was higher in monocytes from AIHA patients compared with normal, returning to normal after glucocorticoid therapy. SIRPα and SHP-1 mRNA expression was upregulated in healthy monocytes treated with dexamethasone compared with basal; however, the erythrophagocytic ability was not altered. Our results point to a minor role of SIRPα and SHP-1 in determining AIHA.     

Use of λgt11 to identify antigenic components of equine herpesvirus 4

A library of the equine herpesvirus 4 (EHV-4) genome was constructed in the gt11 expression vector. Recombinant bacteriophage expressing EHV-4 antigens as beta-galactosidase fusion proteins were detected with rabbit antiserum raised against EHV-4 virions and convalescent horse serum. EHV-4 DNA sequences contained in the immunopositive recombinants were used as hybridization probes for mapping the genes encoding the antigens on the viral genome. The DNA sequence of the probes was determined. Screening the library with rabbit antiserum led to the identification of 40 recombinants, 26 of which were further characterized. Determination of the DNA sequence of the EHV-4 inserts revealed that 23 of the recombinants encode an identical portion of glycoprotein gB. Two of the recombinants encode a portion of the previously unidentified EHV-4 homologue of the EHV-1 immediate early protein. The EHV-4 insert of the remaining recombinant encodes a portion of the previously unidentified EHV-4 homologue of herpes simplex virus 1 (HSV-1) UL36, a tegument protein. Screening the library horse serum led to the identification of three recombinants, one of which encodes the same gB sequence as the gB recombinant recognized with the rabbit serum. The other two contain overlapping sequences that encode a portion of EHV-4 gX.     

Induction of antigen-specific tolerance through hematopoietic stem cell-mediated gene therapy: The future for therapy of autoimmune disease?

Based on the principle that immune ablation followed by HSC-mediated recovery purges disease-causing leukocytes to interrupt autoimmune disease progression, hematopoietic stem cell transplantation (HSCT) has been increasingly used as a treatment for severe autoimmune diseases. Despite clinically-relevant outcomes, HSCT is associated with serious iatrogenic risks and is suitable only for the most serious and intractable diseases. A further limitation of autologous HSCT is that relapse rates can be high, suggesting disease-causing leukocytes are incompletely purged or the environmental and genetic determinants that drive disease remain active. Incorporation of antigen-specific tolerance approaches that synergise with autologous HSCT could reduce or prevent relapse. Further, by reducing the requirement for highly toxic immune-ablation and instead relying on antigen-specific tolerance, the clinical utility of HSCT could be significantly diversified. Substantial progress has been made exploring HSCT-mediated induction of antigen-specific tolerance in animal models but studies have focussed on primarily on prevention of autoimmune diseases. However, as diagnosis of autoimmune disease is often not made until autoimmune disease is well developed and populations of autoantigen-specific pathogenic effector and memory T cells have become well established, immunotherapies must be developed to address effector and memory T-cell responses which have traditionally been considered the key impediment to immunotherapy. Here, focusing on T-cell mediated autoimmune diseases we review progress made in antigen-specific immunotherapy using HSCT-mediated approaches, induction of tolerance in effector and memory T cells and the challenges for progression and clinical application of antigen-specific ‘tolerogenic’ HSCT therapy.     

Risk factor–gene interaction in carotid atherosclerosis: effect of gene polymorphisms of renin-angiotensin system

The risk factor–gene interaction in carotid atherosclerosis was investigated in 205 community-dwelling healthy subjects aged 50 years or more in Japan. The intima–media thickness (IMT) of the common carotid artery was evaluated by ultrasonography with a 7.5-MHz probe. Gene polymorphisms were determined for each subject with angiotensin-converting enzyme (ACE) insertion/deletion (I/D), angiotensinogen (AGT) M235T, angiotensin II type 1 receptor (AT1R) A1166C, and apolipoprotein E (apoE) genotypes. There was no genotype-specific difference in carotid IMT among any genes examined. Combinations of genotypes did not increase carotid IMT compared with subjects without these genotypes. In the total population, multiple regression analysis showed that age, systolic blood pressure (SBP), sex, and body mass index (BMI) were significantly associated with carotid IMT. However, the association between risk factors and IMT was genotype-specific. Age was significantly associated with IMT in ACE D carriers, but not in subjects with the ACE II genotype. Analysis of covariance adjusted with other risk factors showed that the age-dependent change in IMT was significantly different between subjects with the ACE II genotype and the ACE D carriers (F[1.196] = 4.97; P = 0.027). Similarly, the regression of IMT on SBP was significantly different between AGT TT and AGT MT + MM (F[1.196] = 7.20; P = 0.0079). The regression of IMT on BMI was also significantly different between apo E4 carriers and noncarriers (F[1.196] = 6.78; P = 0.0099). Furthermore, general linear model analysis with risk factors, genotype, and risk factor-genotype interactions revealed that the age^*ACE genotype interaction, the SBP^*AGT genotype interaction, and the BMI^*apoE genotype interaction were significantly associated with IMT. These findings further support the role of risk factor-gene interaction in carotid atherosclerosis. Received: January 5, 2001 / Accepted: February 5, 2001     

The catalytic group-I introns of the psbA gene of Chlamydomonas reinhardtii : core structures, ORFs and evolutionary implications

The sequences and predicted secondary structures of the four catalytic group-I introns in the psbA gene of Chlamydomonas reinhardtii, Cr.psbA-1–Cr.psbA-4, have been determined. Cr.psbA-1 and Cr.psbA-4 are subgroup-IA1 introns and have similar secondary structures, except at the 3′ end where Cr.psbA-1 contains a large inverted-repeat domain. Cr.psbA-4 is closely related to intron 1 of the Chlamydomonas moewusii psbA gene, with which it shares the same location, high nucleotide identity in the core, and an identically placed ORF that shows 58% amino-acid identity. Cr.psbA-2 is a subgroup-IA3 intron, and shows similarities to the Chlamydomonas eugametos rRNA intron, Ce.LSU-1. Cr.psbA-3 is a subgroup-IA2 intron, and is remarkably similar to the T4 phage intron, sunY. Interestingly, a degenerate version of Cr.psbA-3 is located in the intergenic region between the chloroplast petA and petD genes. All four introns contain ORFs, which potentially code for basic proteins of 11–38 kDa. The ORFs in introns 2 and 3 contain variants of the GIY-YIG motif; however, the Cr.psbA-2 ORF is free-standing, whereas the Cr.psbA-3 ORF is contiguous and in-frame with the upstream exon. The Cr.psbA-4 ORF contains an H-N-H motif, and possibly a GIY-YIG motif. These data indicate that the C. reinhardtiipsbA introns have multiple origins, and illustrate some of the evolutionary DNA dynamics associated with group-I introns in Chlamydomonas. Received: 24 November 1998 / 23 March 1999