The association between Attention-Deficit-Hyperactivity-Disorder (ADHD) symptoms and disease severity in people with Cystic Fibrosis (pwCF)

BACKGROUND

The hallmarks of Cystic fibrosis (CF), chronic infection and inflammation, require intensive daily treatment to maintain and improve quality of life and outcome. The incidence of Attention Deficit/Hyperactivity Disorder (ADHD) is increased in chronic inflammatory diseases. Previous studies suggested that the prevalence of ADHD in people with CF (pwCF) is higher than in the general population. The objective of this study was to evaluate the association between ADHD symptoms and parameters of CF disease severity, measured by demographic and clinical data.

METHODS

Based on our previous study, the results of ADHD questionnaires and the MOXOCPT (continuous performance task) from 143 pwCF (7-68 years old) were analyzed and linked to patient data such as forced expiratory volume in 1 second (FEV1)%predicted, body mass index (BMI), number of pulmonary exacerbations, days of antibiotic (Abx) treatment and serum inflammatory markers.

RESULTS

A positive correlation between FEV1 and ADHD questionnaire's score (p = 0.046) was observed in the children's group. Furthermore, BMI, white blood cells (WBC) count, and days of Abx treatment showed a positive correlation with some of the MOXOCPT parameters.

CONCLUSION

There is an association between ADHD symptoms and some parameters of CF disease severity. These results highlight the need for an early diagnosis of ADHD in pwCF, which have the potential to improve their ability to deal with the burden of their disease and consequently their quality of life. Additional research is needed to understand the full spectrum of ADHD pathophysiology and the relationship with chronic inflammatory diseases such as CF.

Efficacy of Problem-Solving Intervention to Improve Adherence in Adolescents and Adults with Cystic Fibrosis

BACKGROUND

Adherence to treatment by adolescents and adults with cystic fibrosis (CF) is often poor.

OBJECTIVES

To assess the impact of a focused clinical intervention on adherence in individual patients, including help in problem-solving key barriers to adherence. To implement a patient-centered problem-solving intervention using CF My Way tools. To identify and overcome a selected barrier to adherence.

METHODS

Medication possession ratios (MPRs), number of airway clearance sessions, forced expiratory volume (FEV1), body mass index (BMI), and health-related quality of life (HRQoL) were measured before and after the intervention.

RESULTS

Sixteen patients with CF, aged 23.4 ± 6.7 years, participated. MPR increased for colistimethate sodium and tobramycin inhalations from a median of 21 (range 0-100) to 56 (range 0-100), P = 0.04 and 20 (range 0-100) to 33.3 (range 25-100), P = 0.03, respectively. BMI standard deviation score rose from -0.37 to -0.21, P = 0.05. No significant improvements were found in FEV1, airway clearance, or HRQoL scores.

CONCLUSIONS

The CF My Way problem-solving intervention increased adherence to medical treatments by removing barriers directly related to the needs and goals of young adults with CF.

Dynamics of Mixed- Candida Species Biofilms in Response to Antifungals

Oral infections caused by Candida species, the most commonly isolated human fungal pathogen, are frequently associated with biofilms. Although Candida albicans is the predominant organism found in patients with oral thrush, a biofilm infection, there is an increasing incidence of oral colonization and infections caused by non- albicans Candida species, including C. glabrata, C. dubliniensis, and C. tropicalis, which are frequently more resistant to antifungal treatment. While single-species Candida biofilms have been well studied, considerably less is known about the dynamics of mixed- Candida species biofilms and how these dynamics are altered by antifungal treatment. To address these questions, we developed a quantitative polymerase chain reaction-based approach to determine the precise species composition of mixed- Candida species biofilms formed by clinical isolates and laboratory strains in the presence and absence of clinically relevant concentrations of 3 commonly used antifungals: fluconazole, caspofungin, and amphotericin B. In monospecies biofilms, fluconazole exposure favored growth of C. glabrata and C. tropicalis, while caspofungin generally favored significant growth of all species to a varying degree. Fluconazole was not effective against preformed mixed- Candida species biofilms while amphotericin B was potent. As a general trend, in mixed- Candida species biofilms, C. albicans lost dominance in the presence of antifungals. Interestingly, presence in mixed versus monospecies biofilms reduced susceptibility to amphotericin B for C. tropicalis and C. glabrata. Overall, our data suggest that antifungal treatment favors the growth of specific non- albicans Candida species in mixed- Candida species biofilms.

Rfg1, a protein related to the Saccharomyces cerevisiae hypoxic regulator Rox1, controls filamentous growth and virulence in Candida albicans

Candida albicans, the major fungal pathogen in humans, can undergo a reversible transition from ellipsoidal single cells (blastospores) to filaments composed of elongated cells attached end to end. This transition is thought to allow for rapid colonization of host tissues, facilitating the spread of infection. Here, we report the identification of Rfg1, a transcriptional regulator that controls filamentous growth of C. albicans in an environment-dependent manner. Rfg1 is important for virulence of C. albicans in a mouse model and is shown to control a number of genes that have been implicated in this process. The closest relative to Rfg1 in Saccharomyces cerevisiae is Rox1, a key repressor of hypoxic genes. However, Rfg1 does not appear to play a role in the regulation of hypoxic genes in C. albicans. These results demonstrate that a regulatory protein that controls the hypoxic response in S. cerevisiae controls filamentous growth and virulence in C. albicans. The observations described in this paper raise new and intriguing questions about the evolutionary relationship between these processes.

Targeted recruitment of the Sin3-Rpd3 histone deacetylase complex generates a highly localized domain of repressed chromatin in vivo

Eukaryotic organisms contain a multiprotein complex that includes Rpd3 histone deacetylase and the Sin3 corepressor. The Sin3-Rpd3 complex is recruited to promoters by specific DNA-binding proteins, whereupon it represses transcription. By directly analyzing the chromatin structure of a repressed promoter in yeast cells, we demonstrate that transcriptional repression is associated with localized histone deacetylation. Specifically, we observe decreased acetylation of histones H3 and H4 (preferentially lysines 5 and 12) that depends on the DNA-binding repressor (Ume6), Sin3, and Rpd3. Mapping experiments indicate that the domain of histone deacetylation is highly localized, occurring over a range of one to two nucleosomes. Taken together with previous observations, these results define a novel mechanism of transcriptional repression which involves targeted recruitment of a histone-modifying activity and localized perturbation of chromatin structure.

Histone deacetylase activity of Rpd3 is important for transcriptional repression in vivo

Eukaryotic organisms from yeast to human contain a multiprotein complex that includes Rpd3 histone deacetylase and Sin3 corepressor. The Sin3-Rpd3 complex, when recruited to promoters by specific DNA-binding proteins, can direct transcriptional repression of specific classes of target genes. It has been proposed that the histone deacetylase activity of Rpd3 is important for repression, but direct evidence is lacking. Here, we describe four Rpd3 derivatives with mutations in evolutionarily invariant histidine residues in a putative deacetylation motif. These Rpd3 mutants lack detectable histone deacetylase activity in vitro, but interact normally with Sin3 in vivo. In yeast cells, these catalytically inactive mutants are defective for transcriptional repression. They retain some residual Rpd3 function in vivo, however, suggesting that repression by the Sin3-Rpd3 complex may not be attributable exclusively to its intrinsic histone deacetylase activity. Finally, we show that a human Rpd3 homolog can interact with yeast Sin3 and repress transcription when artificially recruited to a promoter. These results suggest that the histone deacetylase activity of Rpd3 is important, but perhaps not absolutely required, for transcriptional repression in vivo.

Repression by Ume6 involves recruitment of a complex containing Sin3 corepressor and Rpd3 histone deacetylase to target promoters

Sin3 and Rpd3 negatively regulate a diverse set of yeast genes. A mouse Sin3-related protein is a transcriptional corepressor, and a human Rpd3 homolog is a histone deacetylase. Here, we show that Sin3 and Rpd3 are specifically required for transcriptional repression by Ume6, a DNA-binding protein that regulates genes involved in meiosis. A short region of Ume6 is sufficient to repress transcription, and this repression domain mediates a two-hybrid and physical interaction with Sin3. Coimmunoprecipitation and two-hybrid experiments indicate that Sin3 and Rpd3 are associated in a complex distinct from TFIID and Pol II holoenzyme. Rpd3 is specifically required for repression by Sin3, and artificial recruitment of Rpd3 results in repression. These results suggest that repression by Ume6 involves recruitment of a Sin3-Rpd3 complex and targeted histone deacetylation.

The histone deacetylase RPD3 counteracts genomic silencing in Drosophila and yeast

Both position-effect variegation (PEV) in Drosophila and telomeric position-effect in yeast (TPE) result from the mosaic inactivation of genes relocated next to a block of centromeric heterochromatin or next to telomeres. In many aspects, these phenomena are analogous to other epigenetic silencing mechanisms, such as the control of homeotic gene clusters, X-chromosome inactivation and imprinting in mammals, and mating-type control in yeast. Dominant mutations that suppress or enhance PEV are thought to encode either chromatin proteins or factors that directly affect chromatin structure. We have identified an insertional mutation in Drosophila that enhances PEV and reduces transcription of the gene in the eye-antenna imaginal disc. The gene corresponds to that encoding the transcriptional regulator RPD3 in yeast, and to a human histone deacetylase. In yeast, RRD3-deletion strains show enhanced TPE, suggesting a conserved role of the histone deacetylase RPD3 in counteracting genomic silencing. This function of RPD3, which is in contrast to the general correlation between histone acetylation and increased transcription, might be due to a specialized chromatin structure at silenced loci.