Emergence of high-level azithromycin-resistant Neisseria gonorrhoeae causing male urethritis in Johannesburg, South Africa, 2021.

BACKGROUND: In South Africa, Neisseria gonorrhoeae , which is the predominant cause of male urethritis, is treated syndromically using dual ceftriaxone and azithromycin therapy. We determined antimicrobial susceptibilities of N. gonorrhoeae isolates from urethral discharge specimens, and genetically characterised those with elevated minimum inhibitory concentrations (MICs) for first-line antimicrobials. METHODS: Routine antimicrobial susceptibility testing (AST) of N. gonorrhoeae isolates included E-test for ceftriaxone, cefixime and gentamicin and agar dilution for azithromycin and spectinomycin. Neisseria gonorrhoeae Sequence Typing for Antimicrobial Resistance (NG-STAR) was performed for isolates with elevated MICs to identify antimicrobial resistance (AMR) determinants, and Neisseria gonorrhoeae Multi-Antigen Sequence Typing (NG-MAST) was used to determine strain relatedness. RESULTS: N. gonorrhoeae was cultured from urethral discharge swab specimens obtained from 196 of 238 (82.4%) men presenting to a primary healthcare facility in Johannesburg in 2021. All viable isolates were susceptible to extended-spectrum cephalosporins. Four isolates had high azithromycin MICs ranging from 32mg/L to >256mg/L and grouped into two novel NG-MAST and NG-STAR groups. Two isolates from Group 1 (NG-MAST ST20366, NG-STAR ST4322) contained mutated mtrR (G45D) and 23S rRNA (A2059G) alleles, while the two isolates from Group 2 (NG-MAST ST20367, NG-STAR ST4323) had different mutations in mtrR (A39T) and 23S rRNA (C2611T). CONCLUSIONS: We report the first cases of high-level azithromycin resistance in N. gonorrhoeae from South Africa. Continued AMR surveillance is critical to detect increasing azithromycin resistance prevalence in N. gonorrhoeae , which may justify future modifications to the STI syndromic management guidelines.

Molecular Characterization and Detection of Macrolide and Fluoroquinolone Resistance Determinants in Mycoplasma genitalium in South Africa, 2015 to 2018.

BACKGROUND: Antimicrobial resistance in Mycoplasma genitalium is a global concern, as therapeutic options are limited. We aimed to determine the prevalence of macrolide and fluoroquinolone resistance-associated genetic determinants and strain diversity in M. genitalium-positive surveillance specimens from symptomatic primary health care center attendees in South Africa (2015-2018). A secondary objective was to investigate for an association between M. genitalium strain type, HIV serostatus, and antimicrobial resistance. METHODS: A total of 196 M. genitalium-positive specimens from adult males and females presenting with genital discharge to primary health care centers were tested for resistance-associated mutations in 23S rRNA, parC and gyrA. A dual-locus sequence type (DLST) was assigned to M. genitalium strains based on the detection of single nucleotide polymorphisms in the semiconserved 5' region of the mgpB gene (MG191-sequence typing) as well as the enumeration of short tandem repeats within the lipoprotein gene (MG309 short tandem repeat typing). RESULTS: The A2059G mutation in 23S rRNA, associated with macrolide resistance, was detected in 3 of 182 specimens (1.7%; 95% confidence interval, 0.3-4.7). We did not detect gyrA or parC mutations associated with fluoroquinolone resistance in specimens that could be sequenced. Molecular typing with DLST revealed genetic heterogeneity, with DLST 4-11 being the most common M. genitalium strain type detected. There were no associations between DLST and macrolide resistance or HIV infection. CONCLUSIONS: We found a low prevalence of M. genitalium strains with macrolide resistance-associated mutations over a 4-year surveillance period. Ongoing antimicrobial resistance surveillance is essential for informing genital discharge syndromic treatment guidelines.

Predictors of Cell-Associated Human Immunodeficiency Virus (HIV)-1 DNA Over 1 Year in Very Early Treated Infants.

BACKGROUND: Younger age of antiretroviral therapy (ART) initiation is associated with smaller viral reservoirs in perinatally acquired HIV-1 infection, but there is wide variability among early-treated infants. Predictors of this variability are not fully described. METHODS: Sixty-three neonates diagnosed with HIV-1 <48 hours after birth in Johannesburg, South Africa, were started on ART as soon as possible. Fifty-nine (94%) infants received nevirapine prophylaxis from birth until ART start. Viably preserved peripheral blood mononuclear cells (PBMCs) collected at regular intervals to 48 weeks, and from mothers at enrollment, were tested using integrase-targeted, semi-nested, real-time quantitative hydrolysis probe (TaqMan) PCR assays to quantify total HIV-1 subtype C viral DNA (vDNA). Predictors were investigated using generalized estimating equation regression. RESULTS: Thirty-one (49.2%) infants initiated ART <48 hours, 24 (38.1%) <14 days, and 8 (12.7%) >14 days of birth. Three-quarters were infected despite maternal antenatal ART (however, only 9.5% of women had undetectable viral load closest to delivery) and 86% were breastfed. Higher infant CD4+ T-cell percentage and viral load <100 000 copies/mL pre-ART were associated with lower vDNA in the first 48 weeks after ART start. No antenatal maternal ART and breastfeeding were also associated with lower vDNA. Older age at ART initiation had a discernible negative impact when initiated >14 days. CONCLUSIONS: Among very early treated infants, higher CD4+ T-cell percentage and viral load <100 000 copies/mL pre-ART, infection occurring in the absence of maternal antenatal ART, and breastfeeding were associated with lower levels of HIV-1 DNA in the first 48 weeks of treatment. Clinical Trials Registration. clinicaltrials.gov (NCT02431975).

Lack of association of KIR2DL1-R245 and KIR2DL1-C245 with HIV-1 control in black South Africans with HLA-C2.

Activating/inhibitory Killer-cell Immunoglobulin-like Receptors (KIRs) partly regulate Natural Killer (NK) cells. KIR2DL1 allotypes with cysteine at position-245 (KIR2DL1-C245) express at lower levels and demonstrate weaker inhibitory signaling compared to allotypes with arginine at position-245 (KIR2DL1-R245). The functional consequence of either allotype in infectious diseases is unknown. Since NK cells mediate antiviral immunity, we investigated KIR2DL1-R245 and KIR2DL1-C245 in association with HIV-1 virological control in untreated immunocompetent black South Africans. Allotype carriage, determined by KIR2DL1 sequencing, was similar between uninfected South Africans (n = 104) and other black African populations, but differed significantly from Europeans, while no significant differences were noted between uninfected and HIV-1-infected individuals (n = 52). KIR2DL1 expression, measured by flow cytometry, in uninfected individuals showed higher KIR2DL1-R245 expression compared to KIR2DL1-C245 in white donors (n = 27), while black donors (n = 21) generally expressed lower levels of both allotypes. KIR2DL1 expression was reduced in HLA-C2 carriers, most evident in black HLA-C2/C2 donors. KIR2DL1-R245 and KIR2DL1-C245 did not associate with viral load when HLA-C2 ligands were present, however in HLA-C1 homozygotes, individuals with only KIR2DL1-R245, showed lower viral loads compared to carriers of both allotypes. The lack of association of KIR2DL1-R245 or KIR2DL1-C245 with HIV-1 control in HLA-C2 carriers may relate to lower KIR2DL1 expression levels in a population with high HLA-C2 prevalence.

Chronic HIV-1 Infection Alters the Cellular Distribution of FcγRIIIa and the Functional Consequence of the FcγRIIIa-F158V Variant.

Chronic HIV-infection modulates the expression of Fc gamma receptors (FcγRs) on immune cells and their antibody-dependent effector function capability. Given the increasingly recognized importance of antibody-dependent cellular cytotoxicity (ADCC) in HIV-specific immunity, we investigated the cellular distribution of FcγRIIIa on cytotoxic lymphocytes-natural killer cells and CD8+ T cells-and the effect of the FcγRIIIa-F158V variant on ADCC capacity in HIV-infected individuals (n = 23) and healthy controls (n = 23). Study participants were matched for F158V genotypes, carried two copies of the FCGR3A gene and were negative for FcγRIIb expression on NK cells. The distribution of CD56dimFcγRIIIabright and CD56negFcγRIIIabright NK cell subsets, but not FcγRIIIa surface expression, differed significantly between HIV-1 negative and HIV-1 positive donors. NK cell-mediated ADCC responses negatively correlated with the proportion of the immunoregulatory CD56brightFcγRIIIadim/neg cells and were lower in the HIV-1 positive group. Intriguingly, the FcγRIIIa-F158V variant differentially affected the NK-mediated ADCC responses for HIV-1 negative and HIV-1 positive donors. Healthy donors bearing at least one 158V allele had higher ADCC responses compared to those homozygous for the 158F allele (48.1 vs. 34.1%), whereas the opposite was observed for the HIV-infected group (26.4 vs. 34.6%), although not statistically significantly different. Furthermore, FcγRIIIa+CD8bright and FcγRIIIa+CD8dim T cell subsets were observed in both HIV-1 negative and HIV-1 positive donors, with median proportions that were significantly higher in HIV-1 positive donors compared to healthy controls (15.7 vs. 8.3%; P = 0.016 and 18.2 vs. 14.1%; P = 0.038, respectively). Using an HIV-1-specific GranToxiLux assay, we demonstrate that CD8+ T cells mediate ADCC through the delivery of granzyme B, which was overall lower compared to that of autologous NK cells. In conclusion, our findings demonstrate that in the presence of an HIV-1 infection, the cellular distribution of FcγRIIIa is altered and that the functional consequence of FcγRIIIa variant is affected. Importantly, it underscores the need to characterize FcγR expression, cellular distribution and functional consequences of FcγR genetic variants within a specific environment or disease state.

A child with perinatal HIV infection and long-term sustained virological control following antiretroviral treatment cessation.

Understanding HIV remission in rare individuals who initiated antiretroviral therapy (ART) soon after infection and then discontinued, may inform HIV cure interventions. Here we describe features of virus and host of a perinatally HIV-1 infected child with long-term sustained virological control. The child received early limited ART in the Children with HIV Early antiRetroviral therapy (CHER) trial. At age 9.5 years, diagnostic tests for HIV are negative and the child has characteristics similar to uninfected children that include a high CD4:CD8 ratio, low T cell activation and low CCR5 expression. Virus persistence (HIV-1 DNA and plasma RNA) is confirmed with sensitive methods, but replication-competent virus is not detected. The child has weak HIV-specific antibody and T cell responses. Furthermore, we determine his HLA and KIR genotypes. This case aids in understanding post-treatment control and may help design of future intervention strategies.

Age at antiretroviral therapy initiation and cell-associated HIV-1 DNA levels in HIV-1-infected children.

BACKGROUND: The latent viral reservoir is the major obstacle to achieving HIV remission and necessitates life-long antiretroviral therapy (ART) for HIV-infected individuals. Studies in adults and children have found that initiating ART soon after infection is associated with a reduction in the size of the HIV-1 reservoir. Here we quantified cell-associated HIV-1 DNA in early-treated but currently older HIV-infected children suppressed on ART. METHODS: The study participants comprised of a cohort of 146 early-treated children with HIV-1 RNA <50 copies/ml enrolled as part of a clinical trial in Johannesburg, South Africa. A stored buffy coat sample collected after a median 4.3 years on ART and where HIV-1 RNA was <50 copies/ml was tested for cell-associated HIV-1 DNA levels. An in-house, semi-nested real-time quantitative hydrolysis probe PCR assay to detect total HIV-1 subtype C proviral DNA was used. Children were followed prospectively for up to 3 years after this measurement to investigate subsequent HIV-1 RNA rebound/failure while remaining on ART. Age at ART initiation, HIV-1 RNA decline prior to HIV-1 DNA measurement and other factors were investigated. RESULTS: A gradient between age at ART initiation and later HIV-1 DNA levels was observed. When ART was started <2 months of age, the lowest levels of cell-associated HIV-1 DNA (median 1.4 log10copies/106 cells, interquartile range [IQR] 0.95-1.55) were observed compared to ART started at 2-4 months (median 1.68, IQR 1.26-1.97) or 5-14 months of age (median1.98, IQR 1.69-2.25). A low CD4 T-cell count pre-treatment predicted higher levels of HIV-1 DNA on later testing. The probability of HIV-1 RNA rebound >50 copies/ml whilst on ART within 3 years after the DNA measurement was 2.07 (95% CI: 1.352-3.167) times greater if the HIV-1 DNA level was above the median of 55 copies/106 cells. CONCLUSIONS: Cell-associated HIV-1 DNA levels measured after more than 4 years on ART were lower the younger the age of the child when ART was initiated. This marker of the size of the viral reservoir also predicted subsequent viral rebound/treatment failure while ART was sustained. The results provide additional evidence of the benefits of prompt diagnosis and early ART initiation in newborns and infants.

Knock-Down of the 37kDa/67kDa Laminin Receptor LRP/LR Impedes Telomerase Activity.

Cancer has become a major problem worldwide due to its increasing incidence and mortality rates. Both the 37kDa/67kDa laminin receptor (LRP/LR) and telomerase are overexpressed in cancer cells. LRP/LR enhances the invasiveness of cancer cells thereby promoting metastasis, supporting angiogenesis and hampering apoptosis. An essential component of telomerase, hTERT is overexpressed in 85-90% of most cancers. hTERT expression and increased telomerase activity are associated with tumor progression. As LRP/LR and hTERT both play a role in cancer progression, we investigated a possible correlation between LRP/LR and telomerase. LRP/LR and hTERT co-localized in the perinuclear compartment of tumorigenic breast cancer (MDA_MB231) cells and non-tumorigenic human embryonic kidney (HEK293) cells. FLAG® Co-immunoprecipitation assays confirmed an interaction between LRP/LR and hTERT. In addition, flow cytometry revealed that both cell lines displayed high cell surface and intracellular LRP/LR and hTERT levels. Knock-down of LRP/LR by RNAi technology significantly reduced telomerase activity. These results suggest for the first time a novel function of LRP/LR in contributing to telomerase activity. siRNAs targeting LRP/LR may act as a potential alternative therapeutic tool for cancer treatment by (i) blocking metastasis (ii) promoting angiogenesis (iii) inducing apoptosis and (iv) impeding telomerase activity.

Novel patented therapeutic approaches targeting the 37/67 kDa laminin receptor for treatment of cancer and Alzheimer's disease.

INTRODUCTION: The 37/67 kDa high-affinity laminin receptor (laminin receptor precursor/laminin receptor, LRP/LR) is a multi-faceted cellular receptor. It plays a vital role in the malignancy of various cancer types where it is seen to contribute to invasion, adhesion, apoptosis evasion and angiogenesis. Furthermore, it has been found to play an important role in facilitating the processes leading to neurotoxicity in Alzheimer's disease (AD). Various therapeutic options targeting this receptor have been patented with the outlook on application for the treatment/prevention of these diseases. AREAS COVERED: The various roles that LRP/LR plays in cancer, AD and infectious diseases caused by viruses and bacteria have been examined in detail and an overview of the current patented therapeutic strategies targeting this receptor is given. EXPERT OPINION: Molecular tools directed against LRP/LR, such as antibodies and small interfering RNA, could prove to be effective in the prevention of metastasis and angiogenesis while inducing apoptosis in cancers. Moreover, these strategies could also be applied to AD where LRP/LR is seen to facilitate the production and internalization of the neurotoxic Aß peptide. This review provides a comprehensive overview of the mechanisms by which LRP/LR is involved in eliciting pathogenic events, while showing how the use of patented approaches targeting this receptor could be used to treat them.

The 37kDa/67kDa laminin receptor acts as a receptor for Aß42 internalization.

Neuronal loss is a major neuropathological hallmark of Alzheimer's disease (AD). The associations between soluble Aß oligomers and cellular components cause this neurotoxicity. The 37 kDa/67 kDa laminin receptor (LRP/LR) has recently been implicated in Aß pathogenesis. In this study the mechanism underlying the pathological role of LRP/LR was elucidated. Försters Resonance Energy Transfer (FRET) revealed that LRP/LR and Aß form a biologically relevant interaction. The ability of LRP/LR to form stable associations with endogenously shed Aß was confirmed by pull down assays and Aß-ELISAs. Antibody blockade of this association significantly lowered Aß42 induced apoptosis. Furthermore, antibody blockade and shRNA mediated downregulation of LRP/LR significantly hampered Aß42 internalization. These results suggest that LRP/LR is a receptor for Aß42 internalization, mediating its endocytosis and contributing to the cytotoxicity of the neuropeptide by facilitating intra-cellular Aß42 accumulation. These findings recommend anti-LRP/LR specific antibodies and shRNAs as potential therapeutic tools for AD treatment.

High resolution imaging study of interactions between the 37 kDa/67 kDa laminin receptor and APP, beta-secretase and gamma-secretase in Alzheimer's disease.

Alzheimer's disease (AD) is the most prevalent form of dementia affecting the elderly. Neurodegeneration is caused by the amyloid beta (Aß) peptide which is generated from the sequential proteolytic cleavage of the Amyloid Precursor Protein (APP) by the ß- and γ- secretases. Previous reports revealed that the 37 kDa/67 kDa laminin receptor (LRP/LR) is involved in APP processing, however, the exact mechanism by which this occurs remains largely unclear. This study sought to assess whether LRP/LR interacted with APP, ß- or γ-secretase. Detailed confocal microscopy revealed that LRP/LR showed a strong co-localisation with APP, ß- and γ-secretase, respectively, at various sub-cellular locations. Superresolution Structured Illumination Microscopy (SR-SIM) showed that interactions were unlikely between LRP/LR and APP and ß-secretase, respectively, while there was strong co-localisation between LRP/LR and γ-secretase at this 80 nm resolution. FRET was further employed to assess the possibility of protein-protein interactions and only an interaction between LRP/LR and γ-secretase was found. FLAG co-immunoprecipitation confirmed these findings as LRP/LR co-immunoprecipitated with γ-secretase, but failed to do so with APP. These findings indicate that LRP/LR exerts its influence on Aß shedding via a direct interaction with the γ-secretase and possibly an indirect interaction with the ß-secretase.

Anti-LRP/LR specific antibody IgG1-iS18 impedes adhesion and invasion of liver cancer cells.

Two key events, namely adhesion and invasion, are pivotal to the occurrence of metastasis. Importantly, the 37 kDa/67 kDa laminin receptor (LRP/LR) has been implicated in enhancing these two events thus facilitating cancer progression. In the current study, the role of LRP/LR in the adhesion and invasion of liver cancer (HUH-7) and leukaemia (K562) cells was investigated. Flow cytometry revealed that the HUH-7 cells displayed significantly higher cell surface LRP/LR levels compared to the poorly-invasive breast cancer (MCF-7) control cells, whilst the K562 cells displayed significantly lower cell surface LRP/LR levels in comparison to the MCF-7 control cells. However, Western blotting and densitometric analysis revealed that all three tumorigenic cell lines did not differ significantly with regards to total LRP/LR levels. Furthermore, treatment of liver cancer cells with anti-LRP/LR specific antibody IgG1-iS18 (0.2 mg/ml) significantly reduced the adhesive potential of cells to laminin-1 and the invasive potential of cells through the ECM-like Matrigel, whilst leukaemia cells showed no significant differences in both instances. Additionally, Pearson's correlation coefficients suggested direct proportionality between cell surface LRP/LR levels and the adhesive and invasive potential of liver cancer and leukaemia cells. These findings suggest the potential use of anti-LRP/LR specific antibody IgG1-iS18 as an alternative therapeutic tool for metastatic liver cancer through impediment of the LRP/LR- laminin-1 interaction.

Anti-LRP/LR specific antibody IgG1-iS18 and knock-down of LRP/LR by shRNAs rescue cells from Aß42 induced cytotoxicity.

Alzheimer's disease (AD) is characterized by neurofibrillary tangles, senile plaques and neuronal loss. Amyloid beta (Aß) is proposed to elicit neuronal loss through cell surface receptors. As Aß shares common binding partners with the 37 kDa/67 kDa laminin receptor (LRP/LR), we investigated whether these proteins interact and the pathological significance of this association. An LRP/LR-Αß42 interaction was assessed by immunofluorescence microscopy and pull down assays. The cell biological effects were investigated by 3-(4,5-Dimethylthaizol-2-yl)-2,5-diphenyltetrazolium bromide and Bromodeoxyuridine assays. LRP/LR and Αß42 co-localised on the cell surface and formed immobilized complexes suggesting an interaction. Antibody blockade by IgG1-iS18 and shRNA mediated down regulation of LRP/LR significantly enhanced cell viability and proliferation in cells co-treated with Αß42 when compared to cells incubated with Αß42 only. Results suggest that LRP/LR is implicated in Αß42 mediated cytotoxicity and that anti-LRP/LR specific antibodies and shRNAs may serve as potential therapeutic tools for AD.

Anti-LRP/LR specific antibodies and shRNAs impede amyloid beta shedding in Alzheimer's disease.

Alzheimer's disease (AD) is the most prevalent form of dementia. The amyloid beta (Aß) peptide is the predominant candidate aetiological agent and is generated through the sequential proteolytic cleavage of the Amyloid Precursor Protein (APP) by beta (ß) and gamma (γ) secretases. Since the cellular prion protein (PrP(c)) has been shown to regulate Aß shedding, we investigated whether the cellular receptor for PrP(c), namely the 37 kDa/67 kDa Laminin Receptor (LRP/LR) played a role in Aß shedding. Here we show that LRP/LR co-localises with the AD relevant proteins APP, ß- and γ-secretase, respectively. Antibody blockage and shRNA knock-down of LRP/LR reduces Aß shedding, due to impediment of ß-secretase activity, rather than alteration of APP, ß- and γ-secretase levels. These findings indicate that LRP/LR contributes to Aß shedding and recommend anti-LRP/LR specific antibodies and shRNAs as novel therapeutic tools for AD treatment.

In vitro inhibition of angiogenesis by antibodies directed against the 37kDa/67kDa laminin receptor.

The 37kDa/67kDa laminin receptor (LRP/LR) is a central receptor mediating interactions between tumour cells and the basement membrane and is thereby a key player in adhesion and invasion, essential processes in metastatic cancer. To affect continued tumour growth, tumours induce angiogenesis for the constant delivery of nutrients and oxygen. This study aims to determine the blocking effect of the anti-LRP/LR specific antibody, W3 on the angiogenic potential of HUVE (human umbilical vein endothelial) cells. Flow cytometric analysis revealed that 97% of HUVE cells display cell surface LRP/LR. An angiogenesis assay was conducted employing HUVE cells seeded on the basement membrane reconstituent Matrigel™ supplemented with the pro-angiogenic factor vascular endothelial growth factor (VEGF). Post 18h incubation at 37°C tubular structures, namely tube lengths were assessed. Treatment of established tubular structures with 100 µg/ml anti-LRP/LR specific antibody completely blocked angiogenesis. Our findings suggest a central role of the 37kDa/67kDa LRP/LR in tube formation and recommends anti-LRP/LR specific antibodies as potential therapeutic tools for treatment of tumour angiogenesis.

Global Alzheimer Research Summit: basic and clinical research: present and future Alzheimer research.

We report here on the proceedings of the Global Alzheimer Summit that took place September 22-23, 2011 in Madrid, Spain. As Alzheimer disease (AD) is the leading cause of neurodegeneration in elderly individuals and as yet has no effective therapeutic option, it continues to stimulate global research interests. At the conference, leaders in the field of AD research provided insights into current developments in various areas of research, namely molecular mechanisms, genetics, novel aspects of AD research and translational research. Emphasis was also placed on the importance of biomarkers in the diagnosis of AD and development of current therapeutic strategies.

Structural and mechanistic commonalities of amyloid-ß and the prion protein.

Amyloid ß (Aß) is a major causative agent of Alzheime disease. This neurotoxic peptide is generated as a result of the cleavage of the Amyloid-Precursor-Protein (APP) by the action of beta secretase and gamma secretase. The neurotoxicity was previously thought to be the result of aggregation. However, recent studies suggest that the interaction of Aß with numerous cell surface receptors such as N-methyl-D-aspartate (NMDA), receptor for advanced glycosylation end products (RAGE), P75 neurotrophin receptor (P75NTR) as well as cell surface proteins such as the cellular prion protein (PrP(c) ) and heparan sulfate proteoglycans (HSPG) strongly enhances Aß induced apoptosis and thereby contributes to neurotoxicity. This review focuses on the molecular mechanism resulting in Aß-shedding as well as Aß-induced apoptotic processes, genetic risk factors for familial Alzheimer disease and interactions of Aß with cell surface receptors and proteins, with particular emphasis on the cellular prion protein. Furthermore, comparisons are drawn between Alzheimer disease and prion disorders and the role of laminin, an extracellular matrix protein, glycosaminoglycans and the 37 kDa/67 kDa laminin receptor (LRP/LR) have been highlighted with regards to both neurodegenerative diseases.

Alimentary prion infections: Touchdown in the intestine.

Neurodegenerative diseases are caused by proteinaceous aggregates, usually consisting of misfolded proteins which are often typified by a high proportion of ß-sheets, which accumulate in the Central Nervous System. These diseases, including Morbus Alzheimer, Parkinson disease and Transmissible Spongiform Encephalopathies (TSEs)--also termed prion disorders--afflict a substantial proportion of the human population and as such the etiology and pathogenesis of these diseases has been the focus of mounting research. Although many of these diseases arise from genetic mutations or are sporadic in nature, the possible horizontal transmissibility of neurodegenerative diseases poses a great threat to population health. In this article we discuss recent studies which suggest that the "non-transmissible" status bestowed upon Alzheimer and Parkinson diseases may need to be revised as these diseases have been successfully induced through tissue transplants. Furthermore, we highlight the importance of investigating the "natural" mechanism of prion transmission including peroral and perenteral transmission, proposed routes of gastrointestinal uptake and neuroinvasion of ingested infectious prion proteins. We examine the multitude of factors which may influence oral transmissibility and discuss the zoonotic threats which Chronic Wasting Disease (CWD), Bovine Spongiform Encephalopathy (BSE) and Scrapie may pose resulting in vCJD or related disorders. In addition, we suggest that the 37 kDa/67 kDa laminin receptor on the cell surface of enterocytes, a major cell population in the intestine, may play an important role in the intestinal pathophysiology of alimentary prion infections.

Patented biological approaches for the therapeutic modulation of the 37 kDa/67 kDa laminin receptor.

IMPORTANCE OF THE FIELD: The 37/67 kDa laminin receptor precursor/laminin receptor (LRP/LR) represents a multifunctional protein located on the cell surface, in the cytosol and the nucleus. The receptor acts as a mediator for cell adhesion, cell proliferation and cell differentiation. It is a key player in invasion and adhesion, major functions of several important metastatic cancer types. The receptor hampers apoptosis thereby favoring cancer progression. LRP/LR plays a major role as a cell surface receptor in prion disorders and may be of considerable importance for other neurodegenerative diseases such as Alzheimer's disease. A series of viruses including Sindbis virus, Dengue virus and Adeno-associated virus use LRP/LR as attachment receptors. Bacteria and Candida albicans use the receptor for pathogenesis. AREAS COVERED IN THIS REVIEW: Background and patented biological approaches for therapeutic modulation of LRP/LR in neurodegenerative diseases, cancer, viral disorders, bacterial and yeast infections. WHAT THE READER WILL GAIN: A comprehensive review of the role of LRP/LR in infectious and non-infectious diseases and an insightful assessment of published or patented biological approaches for the therapeutic modulation of LRP/LR. TAKE HOME MESSAGE: Molecular tools such as antibodies directed against LRP/LR have the potential to act as promising alternative therapeutics for the treatment of various diseases.

Prion interaction with the 37-kDa/67-kDa laminin receptor on enterocytes as a cellular model for intestinal uptake of prions.

Enterocytes, a major cell population of the intestinal epithelium, represent one possible barrier to the entry of prions after oral exposure. We established a cell culture system employing enterocytes from different species to study alimentary prion interaction with the 37-kDa/67-kDa laminin receptor LRP/LR. Human, bovine, porcine, ovine, and cervid enterocytes were cocultured with brain homogenates from cervid, sheep, and cattle suffering from chronic wasting disease (CWD), scrapie, and bovine spongiform encephalopathy (BSE), respectively. PrP(CWD), ovine PrP(Sc), and PrP(BSE) all colocalized with LRP/LR on human enterocytes. PrP(CWD) failed to colocalize with LRP/LR on bovine, porcine, and ovine enterocytes. Ovine PrP(Sc) colocalized with the receptor on bovine enterocytes, but failed to colocalize with LRP/LR on cervid and porcine enterocytes. PrP(BSE) failed to colocalize with the receptor on cervid and ovine enterocytes. These data suggest possible oral transmissibility of CWD and sheep scrapie to humans and may confirm the oral transmissibility of BSE to humans, resulting in zoonotic variant Creutzfeldt-Jakob disease. CWD might not be transmissible to cattle, pigs, and sheep. Sheep scrapie might have caused BSE, but may not cause transmissible spongiform encephalopathy in cervids and pigs. BSE may not be transmissible to cervids. Our data recommend the enterocyte model system for further investigations of the intestinal pathophysiology of alimentary prion infections.