Native extracellular matrix probes to target patient- and tissue-specific cell-microenvironment interactions by force spectroscopy.

Atomic Force Microscopy (AFM) is successfully used for the quantitative investigation of the cellular mechanosensing of the microenvironment. To this purpose, several force spectroscopy approaches aim at measuring the adhesive forces between two living cells and also between a cell and an appropriate reproduction of the extracellular matrix (ECM), typically exploiting tips suitably functionalised with single components (e.g. collagen, fibronectin) of the ECM. However, these probes only poorly reproduce the complexity of the native cellular microenvironment and consequently of the biological interactions. We developed a novel approach to produce AFM probes that faithfully retain the structural and biochemical complexity of the ECM; this was achieved by attaching to an AFM cantilever a micrometric slice of native decellularised ECM, which was cut by laser microdissection. We demonstrate that these probes preserve the morphological, mechanical, and chemical heterogeneity of the ECM. Native ECM probes can be used in force spectroscopy experiments aimed at targeting cell-microenvironment interactions. Here, we demonstrate the feasibility of dissecting mechanotransductive cell-ECM interactions in the 10 pN range. As proof-of-principle, we tested a rat bladder ECM probe against the AY-27 rat bladder cancer cell line. On the one hand, we obtained reproducible results using different probes derived from the same ECM regions; on the other hand, we detected differences in the adhesion patterns of distinct bladder ECM regions (submucosa, detrusor, and adventitia), in line with the disparities in composition and biophysical properties of these ECM regions. Our results demonstrate that native ECM probes, produced from patient-specific regions of organs and tissues, can be used to investigate cell-microenvironment interactions and early mechanotransductive processes by force spectroscopy. This opens new possibilities in the field of personalised medicine.

Micro-mechanical fingerprints of the rat bladder change in actinic cystitis and tumor presence.

Tissue mechanics determines tissue homeostasis, disease development and progression. Bladder strongly relies on its mechanical properties to perform its physiological function, but these are poorly unveiled under normal and pathological conditions. Here we characterize the mechanical fingerprints at the micro-scale level of the three tissue layers which compose the healthy bladder wall, and identify modifications associated with the onset and progression of pathological conditions (i.e., actinic cystitis and bladder cancer). We use two indentation-based instruments (an Atomic Force Microscope and a nanoindenter) and compare the micromechanical maps with a comprehensive histological analysis. We find that the healthy bladder wall is a mechanically inhomogeneous tissue, with a gradient of increasing stiffness from the urothelium to the lamina propria, which gradually decreases when reaching the muscle outer layer. Stiffening in fibrotic tissues correlate with increased deposition of dense extracellular matrix in the lamina propria. An increase in tissue compliance is observed before the onset and invasion of the tumor. By providing high resolution micromechanical investigation of each tissue layer of the bladder, we depict the intrinsic mechanical heterogeneity of the layers of a healthy bladder as compared with the mechanical properties alterations associated with either actinic cystitis or bladder tumor.

Biophysical and structural characterization of the putative nickel chaperone CooT from Carboxydothermus hydrogenoformans.

Carboxydothermus hydrogenoformans is a model microorganism for the study of [NiFe]-CODH, a key enzyme of carbon cycle in anaerobic microorganisms. The enzyme possesses a unique active site (C-cluster), constituted of a distorted [NiFe3S4] cubane linked to a mononuclear Fe(II) center. Both the biogenesis of the C-cluster and the activation of CODH by nickel insertion remain unclear. Among the three accessory proteins thought to play a role in this latter step (CooC, CooJ, and CooT), CooT is identified as a nickel chaperone involved in CODH maturation in Rhodospirillum rubrum. Here, we structurally and biophysically characterized a putative CooT protein present in C. hydrogenoformans (pChCooT). Despite the low sequence homologies between CooT from R. rubrum (RrCooT) and pChCooT (19% sequence identity), the two proteins share several similarities, such as their overall structure and a solvent-exposed Ni(II)-binding site at the dimer interface. Moreover, the X-ray structure of pChCooT reveals the proximity between the histidine 55, a potential nickel-coordinating residue, and the cysteine 2, a highly conserved key residue in Ni(II)-binding.

Primary, secondary and compensated hypogonadism: a novel risk stratification for infertile men.

Recently, the cohort of men from the European Male Ageing Study has been stratified into different categories distinguishing primary, secondary and compensated hypogonadism. A similar classification has not yet been applied to the infertile population. We performed a cross-sectional study enrolling 786 consecutive Caucasian-European infertile men segregated into eugonadal [normal serum total testosterone (≥3.03 ng/mL) and normal luteinizing hormone (≤9.4 mU/mL)], secondary (low total testosterone, low/normal luteinizing hormone), primary (low total testosterone, elevated luteinizing hormone) and compensated hypogonadism (normal total testosterone; elevated luteinizing hormone). In this cross-sectional study, logistic regression models tested the association between semen parameters, clinical characteristics and the defined gonadal status. Eugonadism, secondary, primary and compensated hypogonadism were found in 80, 15, 2, and 3% of men respectively. Secondary hypogonadal men were at highest risk for obesity [OR (95% CI): 3.48 (1.98-6.01)]. Primary hypogonadal men were those at highest risk for azoospermia [24.54 (6.39-161.39)] and testicular volume <15 mL [12.80 (3.40-83.26)]. Compensated had a similar profile to primary hypogonadal men, while their risk of azoospermia [5.31 (2.25-13.10)] and small testicular volume [8.04 (3.17-24.66)] was lower. The risk of small testicular volume [1.52 (1.01-2.33)] and azoospermia [1.76 (1.09-2.82)] was increased, although in a milder fashion, in secondary hypogonadal men as well. Overall, primary and compensated hypogonadism depicted the worst clinical picture in terms of impaired fertility. Although not specifically designed for infertile men, European Male Ageing Study categories might serve as a clinical stratification tool even in this setting.

Deletion of the thymidine kinase gene induces complete attenuation of the Georgia isolate of African swine fever virus.

African swine fever virus (ASFV) is the etiological agent of a contagious and often lethal viral disease of domestic pigs. There are no vaccines to control Africa swine fever (ASF). Experimental vaccines have been developed using genetically modified live attenuated ASFVs obtained by specifically deleting virus genes involved in virulence, including the thymidine kinase (TK) gene. TK has been shown to be involved in the virulence of several viruses, including ASFV. Here we report the construction of a recombinant virus (ASFV-G/V-ΔTK) obtained by deleting the TK gene in a virulent strain of ASFV Georgia adapted to replicate in Vero cells (ASFV-G/VP30). ASFV-G/P-ΔTK demonstrated decreased replication both in primary swine macrophage cell cultures and in Vero cells compared with ASFV-G/VP30. In vivo, intramuscular administration of up to 10(6) TCID50 of ASFV-G/V-ΔTK does not result in ASF disease. However, these animals are not protected when challenged with the virulent parental Georgia strain.

Granulocyte/monocyte apheresis induces sustained increases in CD4 T cells in HIV-1 infected patients with poor CD4 T cell restoration after suppression of viral replication by HAART.

Current antiretroviral regimens (HAART) are generally effective in reducing viral replication to undetectable levels and inducing a raise in CD4 T cells. However, in approximately 5 to 15% of patients suppression of viral replication is not followed by an increase in CD4 T cells. Such patients may be at increased risk for opportunistic infections. Here we report the results from a phase II open label randomised trial on 30 patients classified as poor responders to HAART who were either subjected to eight consecutive cycles of selective monocyte apheresis or maintained under HAART alone. The results show that monocyte apheresis results in increased CD4 T cell counts which are maintained for at least 31 weeks after last apheresis. This effect was observed only on patients with complete suppression of viral replication. Other effects of monocyte apheresis included a strong reduction of TNF-alpha production in patients with high baseline levels of this cytokine and activation of resting T cells during the apheresis cycles. In two patients with high cellular HIV DNA load apheresis was followed by a 98% reduction, suggesting purging of infected cells. There was no evidence of increased viral replication during or after the apheresis cycles. The data show that monocyte apheresis is safe, well tolerated and may be indicated in patients who respond poorly to HAART.

Interleukin-6 and glucocorticoids synergistically induce human immunodeficiency virus type-1 expression in chronically infected U1 cells by a long terminal repeat independent post-transcriptional mechanism.

BACKGROUND: Glucocorticoids (GC) such as dexamethasone (Dex) can directly upregulate human immunodeficiency virus type-1 (HIV-1) replication in acutely infected cells and potentiate HIV expression from chronically infected promonocytic U1 cells stimulated with tumor necrosis factor-alpha (TNF-alpha). We have here investigated the potential effect of Dex in U1 cells stimulated with interleukin-6 (IL-6), a cytokine inducing virus expression by acting mostly at a post-transcriptional level on the virus life cycle. MATERIALS AND METHODS: Virus production in culture supernatants was evaluated by reverse transcriptase (RT) activity. GC receptor expression was tested by both binding of [3H]-Dexamethasone 21-mesylate and Northern blotting. Cell-associated HIV protein expression was analyzed by Western blotting, whereas both HIV and monocyte chemoattractant protein-1 (MCP-1) RNA accumulation were evaluated by Northern blotting. HIV transcription was tested by long terminal repeat (LTR) chloramphenicol acetyl transferase (CAT) assay after transient transfection of U1 or U937 cells. Formation of activating protein-1 (AP-1) DNA binding complex in nuclear cell extracts was visualized by electrophoretic mobility shift assay (EMSA), whereas ERK1/2 mitogen-activated protein kinase (MAPK) phosphorylation was studied by Western blotting. RESULTS: IL-6 and Dex synergistically induced HIV expression in U1 cells, and this effect was blocked by RU 486. No substantial HIV RNA accumulation was demonstrated in U1 cells co-stimulated with IL-6 and Dex, whereas IL-6 upregulated the expression of MCP-1 RNA, and this effect was inhibited by Dex. In contrast, Dex potentiated IL-6 induced activation of AP-1 and ERK1/2 MAPK phosphorylation, as revealed by EMSA. HIV-1 LTR driven transcription was observed in U1 cells stimulated with TNF-alpha and this effect was potentiated by Dex. In sharp contrast, no induction of LTR-directed CAT activity was observed in transfected U1 cells (or in their parental uninfected U937 cells) stimulated with IL-6 and Dex either alone or in combination. CONCLUSIONS: High levels of virion production can be induced in latently infected cells by stimulation with IL-6 and Dex in the absence of activation of the HIV LTR or viral transcription in spite of activation of both ERK1/2 MAPK and AP-1. These findings suggest the existence of LTR-independent pathways influenced by cytokine and GC through which HIV can maintain substantial levels of protein expression and virion production.

Cytokine and chemokine based control of HIV infection and replication.

HIV infects and propagates into CD4+ T lymphocytes and macrophages, although many other cell types play an important role in virus spreading and pathogenesis. In addition to regulatory viral proteins, the cytokine network has early been implicated as a major controller of the plastic capacity of HIV to spread productively or rather remain silently integrated in the chromosomes of infected cells. The recent discovery of CCR5 and CXCR4 as essential entry co-receptors together with CD4 has highlighted a novel and potentially important step in the pharmacological hunt for more effective antiviral agents. In addition to regulate HIV expression and replication, several cytokines have demonstrated the capacity of up- or down-modulating chemokine receptors including CCR5 and CXCR4 with the consequence of influencing the susceptibility of T cells and macrophages to HIV infection. Pharmacological agents such as pertussis toxin B-oligomer have demonstrated HIV suppressive effects via non competitive binding of CCR5, whereas interferons or interleukin-16 (IL-16) can prevent post-entry steps in HIV expression. At the clinical level, several cytokines or their receptors are useful markers for monitoring disease progression and its consequence on the immune system. Cytokine-based therapy represents a realistic complementary approach to traditional antiretroviral therapy potentially capable of restoring important adaptive or innate immune functions ultimately curtailing HIV spreading and its consequences on the immune system, as exemplified by the experimental clinical use of IL-2.

The binding subunit of pertussis toxin inhibits HIV replication in human macrophages and virus expression in chronically infected promonocytic U1 cells.

We have recently shown that the binding subunit of pertussis toxin (PTX-B) inhibits the entry and replication of macrophage-tropic (R5) HIV-1 strains in activated primary T lymphocytes. Furthermore, PTX-B suppressed the replication of T cell-tropic (X4) viruses at a postentry level in the same cells. In this study we demonstrate that PTX-B profoundly impairs entry and replication of the HIV-1(ADA) (R5), as well as of HIV pseudotyped with either murine leukemia virus or vesicular stomatitis virus envelopes, in primary monocyte-derived macrophages. In addition, PTX-B strongly inhibited X4 HIV-1 replication in U937 promonocytic cells and virus expression in the U937-derived chronically infected U1 cell line stimulated with cytokines such as TNF-alpha and IL-6. Of interest, TNF-alpha-mediated activation of the cellular transcription factor NF-kappaB was unaffected by PTX-B. Therefore, PTX-B may represent a novel and potent inhibitor of HIV-1 replication to be tested for efficacy in infected individuals. In support of this proposition, a genetically modified mutant of PTX (PT-9K/129G), which is safely administered for prevention of Bordetella pertussis infection, showed an in vitro anti-HIV profile superimposable to that of PTX-B.

Professional and community efforts to prevent morbidity and mortality from oral cancer.

BACKGROUND: Oral and pharyngeal cancers cause significant morbidity and mortality, yet there has been little improvement in survival rates in the past 30 years. Because early diagnoses significantly increase survival rates, the authors summarize several approaches to educating and mobilizing the dental profession and the public about this problem. Clinicians are invited to initiate similar programs to catalyze change in their own communities. METHODS: The authors found that many approaches have been used to define the problem and initiate change. These include surveys, focus groups, development of consortia, media programs, flyers, leaflets, prescription pads, legislation and professional endorsements. RESULTS: In Maryland in 1996, only 20 percent of adults reported receiving an oral cancer examination, and most oral cancers were diagnosed at late stages by physicians, not dentists. Results of the public educational campaigns in the regions of New York/New Jersey and Maryland have not been formally evaluated, but there is a developing consensus that oral cancer diagnostic practices in the regions with active educational programs are increasing. CONCLUSIONS: Coalitions or partnerships among individuals and organizations from government, academia, private practice, industry, the general community and the media can affect awareness about oral cancer prevention and early detection on a regional basis. CLINICAL IMPLICATIONS: By increasing awareness of oral cancer among the dental profession and the public, earlier diagnosis of these cancers with consequent improved cure rates is likely. Providing oral cancer diagnostic services as a routine part of an oral examination also may motivate patients to visit the dentist at least once a year.

The B-oligomer of pertussis toxin inhibits human immunodeficiency virus type 1 replication at multiple stages.

We have recently demonstrated that the binding subunit (B-oligomer) of pertussis toxin (PTX-B) deactivates CCR5 and inhibits entry of R5 human immunodeficiency virus type 1 (HIV-1) strains in activated primary T lymphocytes (M. Alfano et al., J. Exp. Med. 190:597-605, 1999). We now present evidence that PTX-B also affects a post-entry step of HIV-1 replication. While PTX-B inhibited fusion induced by R5 but not that induced by X4 envelopes, it blocked infection of T cells with recombinant HIV-1 particles pseudotyped with R5, X4, and even murine leukemia virus or vesicular stomatitis virus envelopes. It also suppressed HIV-1 RNA synthesis in cultures of infected peripheral blood mononuclear cells when new infections had been inhibited by zidovudine, and it reduced Tat-dependent expression of the luciferase reporter gene controlled by the HIV-1 long terminal repeat (LTR). Surprisingly, PTX-B did not affect expression from the cytomegalovirus promoter, nor did it reduce the basal (Tat-independent) expression from the LTR promoter. These results indicate that PTX-B inhibits HIV-1 infection at both the entry and the post-entry stages of viral replication, with the post-entry activity specifically affecting transcription or stability of Tat-stimulated HIV-1 mRNAs.

Human immunodeficiency virus type 1 T-lymphotropic strains enter macrophages via a CD4- and CXCR4-mediated pathway: replication is restricted at a postentry level.

The human immunodeficiency virus type 1 (HIV-1) laboratory strains adapted to T-cell lines, as well as most syncytium-inducing primary isolates, replicate poorly in macrophages, which, beside CD4(+) T lymphocytes, are major targets of HIV-1. In the present work, we used a semiquantitative PCR-based technique to study viral entry into cells, kinetics of reverse transcription, and translocation of the viral DNA into the nucleus of macrophages infected with different HIV-1 strains. Our results demonstrate that T-lymphotropic strains efficiently enter macrophages. Entry was inhibited by a monoclonal antibody against CD4 and by stromal cell-derived factor 1alpha, a natural ligand of CXCR4, suggesting that both CD4 and CXCR4 act as receptors on macrophages for HIV-1 T-lymphotropic strains. Analysis of the kinetics of reverse transcription and nuclear import revealed that the most pronounced differences between T-lymphotropic and macrophagetropic strains occurred at the level of nuclear translocation of viral DNA, although a delay in reverse transcription was also observed. These results suggest that postentry steps are critical for restricted replication of T-lymphotropic HIV-1 strains in macrophages.

Role of cyclophilin A in the uptake of HIV-1 by macrophages and T lymphocytes.

Cyclophilins are a family of proteins that bind cyclosporin A (CsA) and possess peptidyl-prolyl cis-trans isomerase activity. In addition, they are secreted by activated cells and act in a cytokine-like manner, presumably via signaling through a cell surface cyclophilin receptor. More recently, host-derived cyclophilin A (CyPA) has been shown to be incorporated into HIV-1 virions and its incorporation essential for viral infectivity. Here we present evidence supporting a role for viral-associated CyPA in the early events of HIV-1 infection. We report that HIV-1 infection of primary peripheral blood mononuclear cells can be inhibited by: (i) an excess of exogenously added CyPA; (ii) a CsA analogue unable to enter the cells; (iii) neutralizing antibodies to CyPA. Taken together with our observations that recombinant CyPA-induced mobilization of calcium in immortalized, as well as primary, CD4+ T lymphocytes, and that incubation of T cells with iodinated CyPA, followed by chemical cross-linking, resulted in the formation of a high molecular mass complex on the cell surface, these results suggest that HIV-1-associated CyPA mediates an early event in viral infection via interaction with a cellular receptor. This interaction may present a target for anti-HIV therapies and vaccines.

Deficiency of total collagen content and of deoxypyridinoline in intracranial aneurysm walls.

The tissue contents of total collagen and of 3-hydroxypyridinium cross-links, pyridinoline (PYD) and deoxypyridinoline (DPD), were measured in 15 samples of human aneurysms of Willis' Circle obtained at surgery and in 25 autopsy control samples of intracranial arteries of Willis' Circle obtained from 6 subjects who died of other causes than cerebral hemorrhage. PYD and DPD were detected fluorimetrically after HPLC separation. Total collagen content was significantly lower (P < 0.001) in aneurysm samples (mean +/- S.E.M. 2.50 +/- 0.33 nmol of alpha 1(I) collagen chain per mg of delipidated and dried material) than in controls (mean +/- S.E.M. 3.86 +/- 0.14). DPD, but not PYD, content appears to be lower in aneurysm walls. In the aneurysms, the tissue contents of PYD ranged from 212 to 587 pmol/nmol of alpha 1(I) collagen chain (mean +/- S.E.M. 430 +/- 31) while in control samples the values observed ranged from 292 to 642 (mean +/- S.E.M. 471 +/- 21). The tissue content of DPD was measurable only in 6 aneurysm samples (60%), ranging from 12 to 60 pmol/nmol of alpha 1(I) collagen chain (mean +/- S.E.M. 33 +/- 9), while in control samples, DPD content ranged from 30 to 123 (mean +/- S.E.M. 75 +/- 5).

5% amlexanox oral paste, a new treatment for recurrent minor aphthous ulcers: II. Pharmacokinetics and demonstration of clinical safety.

The safety of 5% Amlexanox paste was demonstrated in the following clinical studies: vehicle-controlled safety and efficacy studies; dermal irritation and sensitization studies; single and multiple dose pharmacokinetic studies; and a 28-day in use safety study. Minimal adverse experiences were observed with the 991 subjects that were exposed to 5% Amlexanox paste. No significant irritation or sensitization was associated with 5% Amlexanox paste. Pharmacokinetic studies indicated that systemic levels of Amlexanox are most likely due to normal gastrointestinal absorption with only limited absorption directly through the ulcer. After a 100 mg dose of 5% Amlexanox paste the average maximum concentration of Amlexanox in the serum was 120 ng/ml, occurring 2.4 hours after application. The half-life for elimination of Amlexanox was 3.5 hours, and there was no evidence of accumulation with multiple applications. Overall, the data indicate that 5% Amlexanox paste (Aphthasol) is safe for the treatment of recurrent minor aphthous ulcers.

5% amlexanox oral paste, a new treatment for recurrent minor aphthous ulcers: I. Clinical demonstration of acceleration of healing and resolution of pain.

5% Amlexanox oral paste (Aphthasol) was studied in four vehicle-controlled, randomized, double-blind, parallel group, multicenter, clinical studies involving 1335 subjects who had 1 to 3 aphthous ulcers less than 48 hours old at enrollment. Subjects applied study pastes directly to ulcers four times a day until ulcers healed or for the duration of the study, whichever occurred first. Ulcer size was measured by the investigator and pain was evaluated by the subject; the primary determinant of efficacy was the percentage of subjects with complete healing of ulcers and complete resolution of ulcer pain. The vehicle had marginal beneficial effects as would be expected from a covering material, but statistical significance over no treatment was inconsistent. However, these studies, both individually and collectively, clearly demonstrated in a highly significant and consistent manner that in comparison to both Vehicle and No Treatment 5% Amlexanox oral paste accelerates the resolution of pain and healing of aphthous ulcers.