We have determined that virulent Mycoplasma gallisepticum strain R low is capable of binding the extracellular matrix protein fibronectin. Fibronectin was found to be present in M. gallisepticum R low protein extracts by Western blotting and peptide sequencing. Mycoplasma gallisepticum R high , the attenuated, high-passage derivative of R low , is deficient in this ability. MGA_1199, the M. gallisepticum homologue of the cytadherenceassociated protein P65 from Mycoplasma pneumoniae, and MGA_0928, the M. gallisepticum homologue of the M. pneumoniae cytoskeletal protein HMW3, were identified as fibronectin-binding proteins. Peptides from the regions of MGA_1199 and MGA_0928 exhibiting the highest degree of homology with known fibronectinbinding proteins were shown to bind the gelatin/heparin-binding domain of fibronectin. MGA_1199 and MGA_0928 were shown to be absent and aberrant, respectively, in R high , explaining its lack of fibronectinbinding capability. Consistent with its M. pneumoniae counterpart, MGA_1199 (renamed PlpA) was demonstrated to be surface exposed, despite a lack of classical membrane-spanning domains. Due to its demonstrated topology and the strength of interaction between its binding peptide and fibronectin, we propose that PlpA functions as a fibronectin-binding protein in vivo and may possess atypical transmembrane domains.The avian pathogen Mycoplasma gallisepticum is known to cause chronic respiratory disease in chickens, infectious sinusitis in turkeys, and conjunctivitis in finches (23,33,45,49). The chronic nature of the infection and its effects on weight and egg production render it a pathogen of considerable economic importance to the poultry industry (49). Mycoplasma gallisepticum, together with Mycoplasma pneumoniae and Mycoplasma genitalium, is one of the three most prominent members of the M. pneumoniae phylogenetic cluster. Members of this cluster are pathogens that establish chronic infections and mediate attachment to the host epithelium via molecules present on a complex tip structure (33). The proteins that compose the tip structure, as well as a model for its assembly, have been described using M. pneumoniae (1,18,19).The virulence of strain R has been previously examined by comparing the virulent, low-passage strain (R low ) with the attenuated, high-passage strain (R high ) (29). Initial examination of the protein profiles of R low and R high indicated that three proteins were absent in R high . These proteins have been identified as the primary cytadhesin GapA, the cytadherence-related molecule CrmA, and a high-affinity transport protein, HatA (29,44). Complementation experiments with R high using wild-type gapA and crmA demonstrated that coexpression of GapA and CrmA is essential for cytadherence in M. gallisepticum (27); however, these attachment molecules were not able to completely restore virulence, suggesting that additional differences contribute to the attenuation of the high-passage isolate.With this in mind, we more closely examined the protein profiles of R l...
Atypical antipsychotic medications such as risperidone are widely prescribed for diverse psychiatric indications including schizophrenia, bipolar disorder and depression. These medications have complex pharmacology and are associated with significant endocrine and metabolic side effects. This class of medications also carries FDA black box warnings due to increased risk of death in elderly patients. Clinical reports indicate that patients treated with these medications are more susceptible to infections; however, the underlying mechanisms/pharmacology are unclear. We have previously reported that risperidone and it's active metabolite distributes to the bone marrow in clinically relevant concentrations in preclinical species, leading us to hypothesize that the hematopoietic system may be impacted by these medications. To test this hypothesis, using proteomic and cytokine array technology, we evaluated the expression of genes involved in inflammatory and immune function following short term (5 days) and longer term (4 weeks) treatment in healthy animals. We report that low-dose risperidone treatment results in global immunosuppression in mice, observed following 5 days of dosing and exacerbated with longer term drug treatment (4 weeks). These data are consistent with increased susceptibility to infection in patients administered these medications and have profound implications for the increasing off-label prescribing to vulnerable patient populations including children and the elderly.
Background: Granulomatous meningoencephalomyelitis (GME) and necrotizing meningoencephalitis (NME) are common inflammatory conditions of the central nervous system of dogs. Infectious pathogens, particularly viruses, are suspected to contribute to the etiopathogenesis of GME and NME.Hypothesis: Broadly reactive PCR might aid in the identification of infectious agents in GME and NME. Animals: Sixty-eight client-owned dogs evaluated by necropsy at 1 university referral hospital. Methods: A mixed prospective/retrospective case-control study was performed. Brain tissue prospectively collected at necropsy from GME, NME, and control cases was evaluated by broadly reactive polymerase chain reaction (PCR) for adenoviruses, bunyaviruses, coronaviruses, enteroviruses, flaviviruses, herpesviruses, paramyxoviruses, and parechoviruses. In addition, these tissues were retrospectively evaluated for the presence of mycoplasmas by PCR, culture, and immunohistochemistry (IHC).Results: Brain tissue was collected from 11 GME and 27 NME cases and 30 controls. Viral nucleic acids were not identified in the 6 GME cases, 25 NME cases, and 2 controls evaluated by viral PCR. Mycoplasma canis was identified by Mycoplasma genus PCR in 1/5 GME and 4/25 NME cases and subsequently was cultured from 4/5 GME and 4/8 NME cases as well as 2/9 controls. The IHC did not detect M. canis in any of the 11 GME and 27 NME cases or 14 controls evaluated with strain PG14 polyclonal antiserum.Conclusions and Clinical Importance: The negative results suggest that viral pathogens are not common in the brain tissue of dogs with GME and NME. Further investigation is warranted to determine the importance of M. canis in cases of GME and NME.
Patients with severe mental illness have increased mortality, often linked to cardio-metabolic disease. Non-alcoholic fatty liver disease (NAFLD) incidence is higher in patients with schizophrenia and is exacerbated with antipsychotic treatment. NAFLD is associated with obesity and insulin resistance, both of which are induced by several antipsychotic medications. NAFLD is considered an independent risk factor for cardiovascular disease, the leading cause of death for patients with severe mental illness. Although the clinical literature clearly defines increased risk of NAFLD with antipsychotic therapy, the underlying mechanisms are not understood. Given the complexity of the disorder as well as the complex pharmacology associated with atypical antipsychotic (AA) medications, we chose to use a proteomic approach in healthy mice treated with a low dose of risperidone (RIS) or olanzapine (OLAN) for 28 days to determine effects on development of NAFLD and to identify pathways impacted by AA medications, while removing confounding intrinsic effects of mental illness. Both AA drugs caused development of steatosis in comparison with vehicle controls (p < 0.01) and affected multiple pathways relating to energy metabolism, NAFLD, and immune function. AA-associated alteration in autonomic function appears to be a unifying theme in the regulation of hepatic pathology.
Mumps outbreaks among vaccinated patients have become increasingly common in recent years. While there are multiple conditions driving this re-emergence, convention has suggested that these outbreaks are associated with waning immunity rather than vaccine escape. Molecular evidence from both the ongoing American and Dutch outbreaks in conjunction with recent structural biology studies challenge this convention, and suggest that emergent lineages of mumps virus exhibit key differences in antigenic epitopes from the vaccine strain employed: Jeryl-Lynn 5. The American and Dutch 2016-2017 outbreak lineages were examined using computational biology through the lens of diversity in immunogenic epitopes. Findings are discussed and the laboratory evidence indicating neutralization of heterologous mumps strains by serum from vaccinated individuals is reviewed. Taken together, it is concluded that the number of heterologous epitopes occurring in mumps virus in conjunction with waning immunity is facilitating small outbreaks in vaccinated patients, and that consideration of a polyvalent mumps vaccine is warranted.
Temporomandibular joint osteoarthritis (TMJOA) is a prevalent source of temporomandibular joint disorder (TMD). Women are more commonly diagnosed with TMD and are more likely to seek care at tertiary orofacial pain clinics. Limited knowledge regarding mechanisms underlying temporomandibular joint (TMJ) pain impairs development of improved pain management strategies. In a rat model of unilateral TMJOA, monosodium iodoacetate (MIA) produces joint pathology in a concentration-dependent manner. Unilateral MIA produces alterations in meal patterns in males and females without altering overnight time spent eating or weight across 2 weeks. Monosodium iodoacetate (80 mg/mL)-treated males develop ongoing pain within 2 weeks after MIA injection. Females develop ongoing pain at a 5-fold lower MIA concentration (16.6 mg/m). Monosodium iodoacetate (80 mg/mL)-treated males show spread of tactile hypersensitivity across the face during the first week after injection and then to the fore paws and hind paws during the second week after injection, indicating development of central sensitization. At the lower dose, female rats demonstrate a similar spread of tactile hypersensitivity, whereas male rats do not develop ongoing pain or spread of tactile hypersensitivity outside the area of the ipsilateral temporomandibular joint. These observations indicate that females have a higher susceptibility to development of ongoing pain and central sensitization compared with male rats that is not due to differences in MIA-induced joint pathology. This model of TMJOA pain can be used to explore sex differences in pain processes implicated in development of neuropathic pain, ongoing pain, and central sensitization, allowing for development of individualized strategies for prevention and treatment of TMD joint pain.
There is growing evidence that symbiotic microbes play key roles in host defense, but less is known about how symbiotic microbes mediate pathogen-induced damage to hosts. Here, we use a natural wildlife disease system, house finches and the conjunctival bacterial pathogen Mycoplasma gallisepticum (MG), to experimentally examine the impact of the ocular microbiome on host damage and pathogen virulence factors during infection. We disrupted the ocular bacterial community of healthy finches using an antibiotic that MG is intrinsically resistant to, then inoculated antibiotic- and sham-treated birds with MG. House finches with antibiotic-disrupted ocular microbiomes had more severe MG-induced conjunctival inflammation than birds with unaltered microbiomes, even after accounting for differences in conjunctival MG load. Furthermore, MG cultures from finches with disrupted microbiomes had increased sialidase enzyme and cytadherence activity, traits associated with enhanced virulence in Mycoplasmas, relative to isolates from sham-treated birds. Variation in sialidase activity and cytadherence among isolates was tightly linked with degree of tissue inflammation in hosts, supporting the consideration of these traits as virulence factors in this system. Overall, our results suggest that microbial dysbiosis can result in enhanced virulence of colonizing pathogens, with critical implications for the health of wildlife, domestic animals, and humans.
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