Cutting edge: Compartmentalization of Th1-like noninvariant CD1d-reactive T cells in hepatitis C virus-infected liver

Murine intrahepatic lymphocytes (IHL) are dominated by invariant TCR alpha-chain expressing CD1d-reactive NKT cells, which can cause model hepatitis. Invariant NKT (CD56(+/-)CD161(+)) and recently identified noninvariant CD1d-reactive T cells rapidly produce large amounts of IL-4 and/or IFN-gamma and can regulate Th1/Th2 responses. Human liver contains large numbers of CD56(+) NKT cells but few invariant NKT. Compared with matched peripheral blood T cell lines, primary IHL lines from patients with chronic hepatitis C had high levels of CD161 and CD1d reactivity, but the invariant TCR was rare. CD1d-reactive IHL were strikingly Th1 biased. IHL also demonstrated CD1d-specific cytotoxic activity. Hepatocytes and other liver cells express CD1d. These results identify a novel population of human T cells that could contribute to destructive as well as protective immune responses in the liver. CD1d-reactive T cells may have distinct roles in different tissues.     

Interactions among the A and T units of an ECF-type biotin transporter analyzed by site-specific crosslinking

Energy-coupling factor (ECF) transporters are a huge group of micronutrient importers in prokaryotes. They are composed of a substrate-specific transmembrane protein (S component) and a module consisting of a moderately conserved transmembrane protein (T component) and two ABC ATPase domains (A components). Modules of A and T units may be dedicated to a specific S component or shared by many different S units in an organism. The mode of subunit interactions in ECF transporters is largely unknown. BioMNY, the focus of the present study, is a biotin transporter with a dedicated AT module. It consists of the S unit BioY, the A unit BioM and the T unit BioN. Like all T units, BioN contains two three-amino-acid signatures with a central Arg residue in a cytoplasmic helical region. Our previous work had demonstrated a central role of the two motifs in T units for stability and function of BioMNY and other ECF transporters. Here we show by site-specific crosslinking of pairs of mono-cysteine variants that the Ala-Arg-Ser and Ala-Arg-Gly signatures in BioN are coupling sites to the BioM ATPases. Analysis of 64 BioN-BioM pairs uncovered interactions of both signatures predominantly with a segment of ~13 amino acid residues C-terminal of the Q loop of BioM. Our results further demonstrate that portions of all BioN variants with single Cys residues in the two signatures are crosslinked to homodimers. This finding may point to a dimeric architecture of the T unit in BioMNY complexes.     

Development of a broad-host-range phage cocktail for biocontrol

The aims of this study were to investigate the incidence of different resistance mechanisms to phage K in a bank of Irish Staph aureus hospital strains; and to develop a broad host-range phage cocktail with enhanced lytic activity against those strains which were previously phage resistant. A bank of 180 Staph aureus strains, which included all the sequence types currently in existence in Ireland, were tested for sensitivity to phage K. Twenty nine strains were identified, which did not permit plaque formation. The phage resistance systems in the 29 strain were investigated and it was found that restriction modification (r-m) was evident in 24, an adsorption inhibition mechanism was evident in three, while two were resistant by an unidentified mechanism. Seventeen modified derivatives of phage K were developed which could circumvent all the r-m systems. Nevertheless, six of the modified phage were considered superior in terms of their individual host ranges. These six were pooled as a cocktail with phage K, which then lysed 24 of the 29 resistant strains (97.2% of the entire staphylococcal bank). In conclusion, phage resistant systems affecting phage K are common in Staph. aureus but it is possible to significantly broaden the host-range of this phage for biocontrol applications.     

Cerebral Amyloid Angiopathy in an Aged Sooty Mangabey (Cercocebus atys)

A 26-y-old male sooty mangabey (Cercocebus atys) was found at necropsy to have a moderate degree of cerebral amyloid β (Aβ) angiopathy in superficial and parenchymal blood vessels of the brain. Senile (Aβ) plaques were absent, as were neurofibrillary tangles and other signs of neurodegeneration. Affected blood vessels were arterial, capillary, and, less frequently, venous in nature. Histologically, the Aβ40 isoform was more prevalent than was Aβ42. As in humans but unlike in squirrel monkeys, the density of lesions in this mangabey increased along a rostral-to-caudal gradient. Therefore mangabeys appear to conform to the general tendency of nonhuman primates by developing cerebral Aβ angiopathy in the absence of other indices of Alzheimer-type neuropathology.Abbreviations: Aβ, amyloid β, CAA, cerebral amyloid angiopathy, GFAP, glial fibrillary acidic protein, Iba 1, microglia-expressed calcium-binding proteinOne of the most common microvasculopathies in the aging human brain is cerebral amyloid angiopathy (CAA), a disorder in which various aggregation-prone proteins accumulate in the walls of parenchymal and meningeal blood vessels.^4,9 Most often, the amyloidogenic protein is amyloid β (Aβ), a cleavage product of the Aβ precursor protein and the essential component of senile plaques in Alzheimer disease.^13,43 In the brain vasculature, the basal lamina is a primary site of Aβ deposition.^25,35 Severely affected arterioles show a loss of smooth muscle cells in the tunica media, a weakening of the vascular wall and a propensity to rupture.^3,34 CAA thus increases the risk of intracerebral bleeding and may be responsible for as much as 20% of nontraumatic hemorrhagic stroke in elderly humans.^15,18,35 CAA is present to various degrees in virtually all cases of Alzheimer disease,^15,16,21 but it also occurs independently.²⁴ As is the case for other proteopathies, advancing age is a significant risk factor for CAA.^8,19In humans, CAA most often affects the arteries and arterioles of the brain, particularly those in the leptomeninges and cortex.^2,25 CAA is less frequent in veins and capillaries,²⁵ but capillary CAA can be prominent in some cases.^26,33 The occipital lobe is affected most often^1,32,37 but all cortical regions are vulnerable. CAA is variable in occurrence in the cerebellum and uncommon in deep telencephalic gray structures, white matter, and the brainstem,³⁶ except in severely affected cases.³²Although its specific role in the pathogenesis of Alzheimer disease remains uncertain, there is now strong evidence that dementia is exacerbated by CAA.¹⁴ Furthermore, CAA is independently linked to cognitive decline both in rare familial cases²⁰ and in older humans with idiopathic CAA.^2,20 Despite the prevalence of cerebrovascular amyloidosis in elderly humans, surprisingly little is known about its effect on the brain, in part because of a paucity of natural animal models that closely mimic the human disorder.^17,38Nonhuman primates offer a unique opportunity to view CAA from a comparative perspective, given that they normally generate human-sequence Aβ and develop severe cerebral Aβ amyloidosis in old age, generally in the absence of other changes that characterize Alzheimer disease.¹² Nonhuman primates have the additional advantage that, compared with humans, their relatively small brains enable exhaustive regional analysis of microscopic lesions, something that, for practical reasons, is seldom undertaken in the human brain. Here we present the first investigation of age-associated brain changes in sooty mangabeys, focusing in particular on Aβ deposition and related abnormalities. One of the 2 aged mangabeys analyzed had Aβ deposition in the brain which was almost exclusively in the form of CAA. Remarkably, the vessel types affected and the regional distribution of CAA more closely resembled the pattern seen in humans than that in other nonhuman primates, particularly squirrel monkeys.⁶ Differences and similarities in CAA among primate species could provide fresh insights into the development of cerebral amyloidosis and related disorders in older humans.     

Design and synthesis of novel enhanced water soluble hydroxyethyl analogs of combretastatin A-4

Thirteen hydroxyethyl- analogs of combretastatin A-4 (CA-4) that contain the 1-(1′-hydroxyethyl)-1-(3″,4″,5″-trimethoxyphenyl)-2-(substituted phenyl)ethene framework were synthesized. Molecular modeling studies at the DFT level showed that compound 3j adopts a ‘twisted’ conformation mimicking CA-4. The cytotoxicity of the novel compounds against the growth of murine B16 melanoma and L1210 lymphoma cells in culture was measured using an MTT assay. Three analogs 3f, 3h, and 3j were active. Of these, 3j, which has the same substituents as CA-4 and IC₅₀ values of 16.1 and 4.1 μM against B16 and L1210 cells, respectively, was selected for further biological evaluation. The activity of 3j was verified by the NCI 60 cell line screen. Compound 3j causes microtubule depolymerization in A-10 cells with an EC₅₀ of 21.2 μM. Analog 3j, which has excellent water solubility of 479 μM, had antitumor activity in a syngeneic L1210 murine model.     

Effect of a nutrition supplement and physical activity program on pneumonia and walking capacity in Chilean older people: a factorial cluster randomized trial

Background

Ageing is associated with increased risk of poor health and functional decline. Uncertainties about the health-related benefits of nutrition and physical activity for older people have precluded their widespread implementation. We investigated the effectiveness and cost-effectiveness of a national nutritional supplementation program and/or a physical activity intervention among older people in Chile.

Methods and Findings

We conducted a cluster randomized factorial trial among low to middle socioeconomic status adults aged 65–67.9 years living in Santiago, Chile. We randomized 28 clusters (health centers) into the study and recruited 2,799 individuals in 2005 (∼100 per cluster). The interventions were a daily micronutrient-rich nutritional supplement, or two 1-hour physical activity classes per week, or both interventions, or neither, for 24 months. The primary outcomes, assessed blind to allocation, were incidence of pneumonia over 24 months, and physical function assessed by walking capacity 24 months after enrolment. Adherence was good for the nutritional supplement (∼75%), and moderate for the physical activity intervention (∼43%). Over 24 months the incidence rate of pneumonia did not differ between intervention and control clusters (32.5 versus 32.6 per 1,000 person years respectively; risk ratio = 1.00; 95% confidence interval 0.61–1.63; p = 0.99). In intention-to-treat analysis, after 24 months there was a significant difference in walking capacity between the intervention and control clusters (mean difference 33.8 meters; 95% confidence interval 13.9–53.8; p = 0.001). The overall cost of the physical activity intervention over 24 months was US$164/participant; equivalent to US$4.84/extra meter walked. The number of falls and fractures was balanced across physical activity intervention arms and no serious adverse events were reported for either intervention.

Conclusions

Chile''s nutritional supplementation program for older people is not effective in reducing the incidence of pneumonia. This trial suggests that the provision of locally accessible physical activity classes in a transition economy population can be a cost-effective means of enhancing physical function in later life.

Trial registration

Current Controlled Trials ISRCTN 48153354 Please see later in the article for the Editors'' Summary