Qualitative Research to Understand the Patient Experience and Evaluate Content Validity of the Chronic Ocular Pain Questionnaire (COP-Q).

INTRODUCTION: Chronic ocular surface pain (COSP) is described as a persistent, moderate-to-severe pain at the ocular surface lasting more than 3 months. Symptoms of COSP have a significant impact on patients' vision-dependent activities of daily living (ADL) and distal health-related quality of life (HRQoL). To adequately capture patient perspectives in clinical trials, patient-reported outcome (PRO) measures must demonstrate sufficient evidence of content validity in the target population. This study aimed to explore the patient experience of living with COSP and evaluate content validity of the newly developed Chronic Ocular Pain Questionnaire (COP-Q) for use in COSP clinical trials. METHODS: Qualitative, combined concept elicitation (CE) and cognitive debriefing (CD) interviews were conducted with 24 patients experiencing COSP symptoms in the USA. Interviews were supplemented with real-time data collection via a daily diary app task in a subset of patients (n = 15) to explore the day-to-day patient experience. Three healthcare professionals (HCPs) from the USA, Canada, and France were also interviewed to provide a clinical perspective. CE results were used to further inform development of a conceptual model and to refine PRO items/response options. CD interviews assessed relevance and understanding of the COP-Q. Interviews were conducted across multiple rounds to allow item modifications and subsequent testing. RESULTS: Eye pain, eye itch, burning sensation, eye dryness, eye irritation, foreign body sensation, eye fatigue, and eye grittiness were the most frequently reported symptoms impacting vision-dependent ADL (e.g., reading, using digital devices, driving) and wider HRQoL (e.g., emotional wellbeing, social functioning, work). COP-Q instructions, items, and response scales were understood, and concepts were considered relevant. Feedback supported modifications to instruction/item wording and confirmed the most appropriate recall periods. CONCLUSIONS: Findings support content validity of the COP-Q for use in COSP populations. Ongoing research to evaluate psychometric validity of the COP-Q will support future use of the instrument in clinical trial efficacy endpoints.

Development and content validity assessment of the Dry Eye Disease Questionnaire in patients with dry eye disease, meibomian gland dysfunction, and Sjögren's syndrome dry eye disease.

BACKGROUND: Dry eye disease (DED), Meibomian gland dysfunction (MGD), and Sjögren's syndrome dry eye disease (SS-DED) are eye dryness conditions that show significant overlap in various symptoms of ocular discomfort. The aim of this study was to qualitatively explore the patient experience and evaluate content validity of the newly developed Dry Eye Disease Questionnaire (DED-Q). METHODS: Semi-structured interviews were conducted with 61 US adults who reported experiencing ocular symptoms due to their physician-confirmed primary diagnosis of DED (n = 21), MGD (n = 20), or SS-DED (n = 20). The open-ended concept-elicitation phase was followed by cognitive debriefing (CD) of the DED-Q to evaluate participants' understanding and relevance of the instructions, items, response options, and recall periods. Interviews were also conducted with eight specialist healthcare professionals to assess clinical relevance of the concepts included. Verbatim interview transcripts were analyzed using thematic analysis in ATLAS.ti v8 software. RESULTS: A total of 29 symptoms and 14 impacts on quality of life were reported across participant interviews. Primary ocular symptoms reported included eye dryness (n = 61/61; 100%), eye irritation (n = 55/61; 90%), eye itch (n = 54/61; 89%), burning sensation (n = 52/61; 85%), and foreign body sensation (n = 51/61; 84%). The most impacted aspects of daily life were using digital screens (n = 46/61; 75%), driving (n = 45/61; 74%), working (n = 39/61; 64%), and reading (n = 37/61; 61%). CD findings showed most participants had good understanding of DED-Q items and confirmed most concepts were relevant to the lived experience of their condition. Aside from few minor changes to the items and examples to facilitate more accurate interpretation, the proposed instruction wording was modified for various symptom and impact modules to encourage participants to focus only on dry eye vision problems. CONCLUSIONS: This research identified multiple prevalent symptoms and impacts of DED, MGD, and SS-DED, most of which were similar across the conditions. The DED-Q was confirmed to be a content-valid PRO measure suitable for use in clinical studies to assess the patient experience of DED, MGD, and SS-DED. Future work will focus on evaluating the psychometric properties of the DED-Q for use as an efficacy endpoint in clinical trials.

Dry Eye Disease (DED), Meibomian Gland Dysfunction (MGD), and Sjögren's Syndrome Dry Eye Disease (SS-DED) are conditions related to dryness of the eye. There is no suitable patient-reported outcome (PRO) measure available for use across the three conditions. Interviews were conducted with 61 participants with any of the three conditions to understand the symptoms they experience and their impact on daily life. The findings were used to refine the content of a new PRO measure, the Dry Eye Disease Questionnaire (DED-Q). To evaluate the suitability of the DED-Q, participants were also asked to complete each item of the DED-Q during the interview and share their understanding of the item wording, response options and the recall period. Interviews were also conducted with eight healthcare professionals (HCPs). The main symptoms reported by the patients across three conditions were eye dryness, eye irritation, eye itch, burning sensation, and foreign body sensation. The symptoms caused difficulties in performing activities such as using digital screens, driving, working, and reading. Almost all participants demonstrated good understanding of the items on the DED-Q and found them to be relevant to their experience of their condition. The HCPs also confirmed that the concepts covered in the DED-Q were relevant to assess the participant experience across these conditions. Next steps will involve a more detailed analysis of the measurement properties of the DED-Q to confirm its usefulness in supporting primary or secondary endpoints in clinical trials.

Study of Plasmodium falciparum DHHC palmitoyl transferases identifies a role for PfDHHC9 in gametocytogenesis.

Palmitoylation is the post-translational reversible addition of the acyl moiety, palmitate, to cysteine residues of proteins and is involved in regulating protein trafficking, localization, stability and function. The Aspartate-Histidine-Histidine-Cysteine (DHHC) protein family, named for their highly conserved DHHC signature motif, is thought to be responsible for catalysing protein palmitoylation. Palmitoylation is widespread in all eukaryotes, including the malaria parasite, Plasmodium falciparum, where over 400 palmitoylated proteins are present in the asexual intraerythrocytic schizont stage parasites, including proteins involved in key aspects of parasite maturation and development. The P. falciparum genome includes 12 proteins containing the conserved DHHC motif. In this study, we adapted a palmitoyl-transferase activity assay for use with P. falciparum proteins and demonstrated for the first time that P. falciparum DHHC proteins are responsible for the palmitoylation of P. falciparum substrates. This assay also reveals that multiple DHHCs are capable of palmitoylating the same substrate, indicating functional redundancy at least in vitro. To test whether functional redundancy also exists in vivo, we investigated the endogenous localization and essentiality of a subset of schizont-expressed PfDHHC proteins. Individual PfDHHC proteins localized to distinct organelles, including parasite-specific organelles such as the rhoptries and inner membrane complex. Knock-out studies identified individual DHHCs that may be essential for blood-stage growth and others that were functionally redundant in the blood stages but may have functions in other stages of parasite development. Supporting this hypothesis, disruption of PfDHHC9 had no effect on blood-stage growth but reduced the formation of gametocytes, suggesting that this protein could be exploited as a transmission-blocking target. The localization and stage-specific expression of the DHHC proteins may be important for regulating their substrate specificity and thus may provide a path for inhibitor development.

Palmitoylation and palmitoyl-transferases in Plasmodium parasites.

Protein post-translational modifications (PTM) are commonly used to regulate biological processes. Protein S-acylation is an enzymatically regulated reversible modification that has been shown to modulate protein localization, activity and membrane binding. Proteome-scale discovery on Plasmodium falciparum schizonts has revealed a complement of more than 400 palmitoylated proteins, including those essential for host invasion and drug resistance. The wide regulatory affect on this species is endorsed by the presence of 12 proteins containing the conserved DHHC-CRD (DHHC motif within a cysteine-rich domain) that is associated with palmitoyl-transferase activity. Genetic interrogation of these enzymes in Apicomplexa has revealed essentiality and distinct localization at cellular compartments; these features are species specific and are not observed in yeast. It is clear that palmitoylation has an elaborate role in Plasmodium biology and opens intriguing questions on the functional consequence of this group of acylation modifications and how the protein S-acyl transferases (PATs) orchestrate molecular events.

A human genome-wide screen for regulators of clathrin-coated vesicle formation reveals an unexpected role for the V-ATPase.

Clathrin-mediated endocytosis is essential for a wide range of cellular functions. We used a multi-step siRNA-based screening strategy to identify regulators of the first step in clathrin-mediated endocytosis, formation of clathrin-coated vesicles (CCVs) at the plasma membrane. A primary genome-wide screen identified 334 hits that caused accumulation of CCV cargo on the cell surface. A secondary screen identified 92 hits that inhibited cargo uptake and/or altered the morphology of clathrin-coated structures. The hits include components of four functional complexes: coat proteins, V-ATPase subunits, spliceosome-associated proteins and acetyltransferase subunits. Electron microscopy revealed that V-ATPase depletion caused the cell to form aberrant non-constricted clathrin-coated structures at the plasma membrane. The V-ATPase-knockdown phenotype was rescued by addition of exogenous cholesterol, indicating that the knockdown blocks clathrin-mediated endocytosis by preventing cholesterol from recycling from endosomes back to the plasma membrane.

Distinct and overlapping roles for AP-1 and GGAs revealed by the "knocksideways" system.

Although adaptor protein complex 1 (AP-1) and Golgi-localized, γ ear-containing, ADP-ribosylation factor-binding proteins (GGAs) are both adaptors for clathrin-mediated intracellular trafficking, the pathways they mediate and their relationship to each other remain open questions. To tease apart the functions of AP-1 and GGAs, we rapidly inactivated each adaptor using the "knocksideways" system and then compared the protein composition of clathrin-coated vesicle (CCV) fractions from control and knocksideways cells. The AP-1 knocksideways resulted in a dramatic and unexpected loss of GGA2 from CCVs. Over 30 other peripheral membrane proteins and over 30 transmembrane proteins were also depleted, including several mutated in genetic disorders, indicating that AP-1 acts as a linchpin for intracellular CCV formation. In contrast, the GGA2 knocksideways affected only lysosomal hydrolases and their receptors. We propose that there are at least two populations of intracellular CCVs: one containing both GGAs and AP-1 for anterograde trafficking and another containing AP-1 for retrograde trafficking. Our study shows that knocksideways and proteomics are a powerful combination for investigating protein function, which can potentially be used on many different types of proteins.