4 results on '"Sameer Andani"'
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2. Corynebacterium Species Inhibit Streptococcus pneumoniae Colonization and Infection of the Mouse Airway
- Author
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Kadi J. Horn, Alexander C. Jaberi Vivar, Vera Arenas, Sameer Andani, Edward N. Janoff, and Sarah E. Clark
- Subjects
Corynebacterium ,Streptococcus pneumoniae ,nasopharyngeal colonization ,lung infection ,pneumonia ,pneumococcus ,Microbiology ,QR1-502 - Abstract
The stability and composition of the airway microbiome is an important determinant of respiratory health. Some airway bacteria are considered to be beneficial due to their potential to impede the acquisition and persistence of opportunistic bacterial pathogens such as Streptococcus pneumoniae. Among such organisms, the presence of Corynebacterium species correlates with reduced S. pneumoniae in both adults and children, in whom Corynebacterium abundance is predictive of S. pneumoniae infection risk. Previously, Corynebacterium accolens was shown to express a lipase which cleaves host lipids, resulting in the production of fatty acids that inhibit growth of S. pneumoniae in vitro. However, it was unclear whether this mechanism contributes to Corynebacterium-S. pneumoniae interactions in vivo. To address this question, we developed a mouse model for Corynebacterium colonization in which colonization with either C. accolens or another species, Corynebacterium amycolatum, significantly reduced S. pneumoniae acquisition in the upper airway and infection in the lung. Moreover, the lungs of co-infected mice had reduced pro-inflammatory cytokines and inflammatory myeloid cells, indicating resolution of infection-associated inflammation. The inhibitory effect of C. accolens on S. pneumoniae in vivo was mediated by lipase-dependent and independent effects, indicating that both this and other bacterial factors contribute to Corynebacterium-mediated protection in the airway. We also identified a previously uncharacterized bacterial lipase in C. amycolatum that is required for inhibition of S. pneumoniae growth in vitro. Together, these findings demonstrate the protective potential of airway Corynebacterium species and establish a new model for investigating the impact of commensal microbiota, such as Corynebacterium, on maintaining respiratory health.
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- 2022
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3. Prevalence of RFC1-Mediated Spinocerebellar Ataxia in a United States Ataxia Cohort
- Author
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Brent L. Fogel, Giacomo Glotzer, Christopher M. Gomez, Susan Perlman, Vikram Khurana, Yuanming Mao, Paul J. Lockhart, Darice Wong, Dona Aboud Syriani, Claudio M. de Gusmao, Soma Das, Sharon Hassin-Baer, and Sameer Andani
- Subjects
0303 health sciences ,Vestibular areflexia ,medicine.medical_specialty ,congenital, hereditary, and neonatal diseases and abnormalities ,Ataxia ,Cerebellar ataxia ,business.industry ,030305 genetics & heredity ,medicine.disease ,RFC1 ,3. Good health ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,Cohort ,Spinocerebellar ataxia ,Medicine ,medicine.symptom ,Allele ,business ,Trinucleotide repeat expansion ,030217 neurology & neurosurgery - Abstract
ObjectiveRepeat expansions in RFC1 and DAB1 have recently been identified as causing cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS) and spinocerebellar ataxia 37 (SCA37), respectively. We evaluated the prevalence of these repeat-expansions in an undiagnosed ataxia cohort from the United States.MethodsA cohort of 596 patients with undiagnosed familial or sporadic cerebellar ataxia were evaluated at a tertiary referral ataxia center and excluded for common genetic causes of cerebellar ataxia. Patients were then screened for the presence of pathogenic repeat expansions in RFC1 (AAGGG) and DAB1 (ATTTC) using fluorescent repeat primed polymerase chain reaction (RP-PCR). Two additional undiagnosed ataxia cohorts from different centers, totaling 96 and 13 patients respectively, were subsequently screened for RFC1 resulting in a combined 705 subjects tested.ResultsIn the initial cohort, 42 samples were identified with one expanded allele in the RFC1 gene (7.0%), and 9 had two expanded alleles (1.5%). For the additional cohorts, we found 12 heterozygous samples (12.5%) and 7 biallelic samples (7.3%) in the larger cohort, and 1 heterozygous sample (7.7%) and 3 biallelic samples (23%) in the second. In total, 19 patients were identified with biallelic repeat expansions in RFC1 (2.7%). Of these 19 patients, 6 (32%) had a clinical diagnosis of CANVAS, 10 had cerebellar ataxia with neuropathy (53%), and 3 had spinocerebellar ataxia (16%). No patients were identified with expansions in the DAB1 gene.ConclusionIn a large undiagnosed ataxia cohort from the United States, biallelic pathogenic repeat expansion in RFC1 was observed in 2.7%. Testing should be strongly considered in ataxia patients, especially those with CANVAS or neuropathy.
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- 2019
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- View/download PDF
4. Prevalence of RFC1-mediated spinocerebellar ataxia in a North American ataxia cohort
- Author
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Susan Perlman, Darice Wong, Paul J. Lockhart, Dona Aboud Syriani, Brent L. Fogel, Christopher M. Gomez, Vikram Khurana, Soma Das, Claudio M. de Gusmao, Yuanming Mao, May Sanyoura, Sharon Hassin-Baer, Sameer Andani, and Giacomo Glotzer
- Subjects
congenital, hereditary, and neonatal diseases and abnormalities ,medicine.medical_specialty ,Vestibular areflexia ,Ataxia ,Cerebellar ataxia ,business.industry ,RFC1 ,medicine.disease ,Gastroenterology ,Article ,Internal medicine ,Cohort ,medicine ,Spinocerebellar ataxia ,Neurology (clinical) ,Allele ,medicine.symptom ,business ,Trinucleotide repeat expansion ,Genetics (clinical) - Abstract
ObjectiveWe evaluated the prevalence of pathogenic repeat expansions in replication factor C subunit 1 (RFC1) and disabled adaptor protein 1 (DAB1) in an undiagnosed ataxia cohort from North America.MethodsA cohort of 596 predominantly adult-onset patients with undiagnosed familial or sporadic cerebellar ataxia was evaluated at a tertiary referral ataxia center and excluded for common genetic causes of cerebellar ataxia. Patients were then screened for the presence of pathogenic repeat expansions in RFC1 (AAGGG) and DAB1 (ATTTC) using fluorescent repeat-primed PCR (RP-PCR). Two additional undiagnosed ataxia cohorts from different centers, totaling 302 and 13 patients, respectively, were subsequently screened for RFC1, resulting in a combined 911 subjects tested.ResultsIn the initial cohort, 41 samples were identified with 1 expanded allele in the RFC1 gene (6.9%), and 9 had 2 expanded alleles (1.5%). For the additional cohorts, we found 20 heterozygous samples (6.6%) and 17 biallelic samples (5.6%) in the larger cohort and 1 heterozygous sample (7.7%) and 3 biallelic samples (23%) in the second. In total, 29 patients were identified with biallelic repeat expansions in RFC1 (3.2%). Of these 29 patients, 8 (28%) had a clinical diagnosis of cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS), 14 had cerebellar ataxia with neuropathy (48%), 4 had pure cerebellar ataxia (14%), and 3 had spinocerebellar ataxia (10%). No patients were identified with expansions in the DAB1 gene (spinocerebellar ataxia type 37).ConclusionsIn a large undiagnosed ataxia cohort from North America, biallelic pathogenic repeat expansion in RFC1 was observed in 3.2%. Testing should be strongly considered in patients with ataxia, especially those with CANVAS or neuropathy.
- Published
- 2020
- Full Text
- View/download PDF
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