Curcumin activates the haem oxygenase-1 gene via regulation of Nrf2 and the antioxidant-responsive element

The transcription factor Nrf2, which normally exists in an inactive state as a consequence of binding to a cytoskeleton-associated protein Keap1, can be activated by redox-dependent stimuli. Alteration of the Nrf2-Keap1 interaction enables Nrf2 to translocate to the nucleus, bind to the antioxidant-responsive element (ARE) and initiate the transcription of genes coding for detoxifying enzymes and cytoprotective proteins. This response is also triggered by a class of electrophilic compounds including polyphenols and plant-derived constituents. Recently, the natural antioxidants curcumin and caffeic acid phenethyl ester (CAPE) have been identified as potent inducers of haem oxygenase-1 (HO-1), a redox-sensitive inducible protein that provides protection against various forms of stress. Here, we show that in renal epithelial cells both curcumin and CAPE stimulate the expression of Nrf2 in a concentration- and time-dependent manner. This effect was associated with a significant increase in HO-1 protein expression and haem oxygenase activity. From several lines of investigation we also report that curcumin (and, by inference, CAPE) stimulates ho-1 gene activity by promoting inactivation of the Nrf2-Keap1 complex, leading to increased Nrf2 binding to the resident ho-1 AREs. Moreover, using antibodies and specific inhibitors of the mitogen-activated protein kinase (MAPK) pathways, we provide data implicating p38 MAPK in curcumin-mediated ho-1 induction. Taken together, these results demonstrate that induction of HO-1 by curcumin and CAPE requires the activation of the Nrf2/ARE pathway.

Nrf2 Is a Key Transcription Factor That Regulates Antioxidant Defense in Macrophages and Epithelial Cells: Protecting against the Proinflammatory and Oxidizing Effects of Diesel Exhaust Chemicals

The proinflammatory effects of particulate pollutants, including diesel exhaust particles (DEP), are related to their content of redox cycling chemicals and their ability to generate oxidative stress in the respiratory tract. An antioxidant defense pathway, which involves phase II enzyme expression, protects against the pro-oxidative and proinflammatory effects of DEP. The expression of enzymes, including heme oxygenase-1 (HO-1) and GST, is dependent on the activity of a genetic antioxidant response element in their promoters. In this study we investigated the mechanism by which redox cycling organic chemicals, prepared from DEP, induce phase II enzyme expression as a protective response. We demonstrate that aromatic and polar DEP fractions, which are enriched in polycyclic aromatic hydrocarbons and quinones, respectively, induce the expression of HO-1, GST, and other phase II enzymes in macrophages and epithelial cells. We show that HO-1 expression is mediated through accumulation of the bZIP transcription factor, Nrf2, in the nucleus, and that Nrf2 gene targeting significantly weakens this response. Nrf2 accumulation and subsequent activation of the antioxidant response element is regulated by the proteasomal degradation of Nrf2. This pathway is sensitive to pro-oxidative and electrophilic DEP chemicals and is also activated by ambient ultrafine particles. We propose that Nrf2-mediated phase II enzyme expression protects against the proinflammatory effects of particulate pollutants in the setting of allergic inflammation and asthma.

Degradation of transcription factor Nrf2 via the ubiquitin-proteasome pathway and stabilization by cadmium

Nrf2 mediates inducer-dependent activation of the heme oxygenase-1 (HO-1) gene (Alam, J., Stewart, D., Touchard, C., Boinapally, S., Choi, A. M., and Cook, J. L. (1999) J. Biol. Chem. 274, 26071-26078), but the mechanism by which HO-1 inducers regulate Nrf2 function is not known. Treatment of mouse hepatoma (Hepa) cells with 50 microm CdCl(2) increased the amount of Nrf2 protein in a time-dependent manner; induction was observed within 30 min, prior to the accumulation of HO-1 mRNA. Cadmium did not significantly affect the steady-state level of Nrf2 mRNA or the initial rate of Nrf2 protein synthesis but increased the half-life of Nrf2 from approximately 13 to 100 min. Proteasome inhibitors, but not other protease inhibitors, enhanced the expression of Nrf2, and ubiquitinylated Nrf2 was detected after proteasome inhibition. Cycloheximide inhibited cadmium-stimulated Nrf2 expression and DNA binding activity and attenuated HO-1 mRNA accumulation. Conversely, proteasome inhibitors enhanced HO-1 mRNA and protein accumulation by a Nrf2-dependent mechanism. Together, these results indicate that Nrf2 is targeted for rapid degradation by the ubiquitin-proteasome pathway and that cadmium delays the rate of Nrf2 degradation leading to ho-1 gene activation.

Heme activates the heme oxygenase-1 gene in renal epithelial cells by stabilizing Nrf2

The mechanism of heme oxygenase-1 gene (ho-1) activation by heme in immortalized rat proximal tubular epithelial cells was examined. Analysis of the ho-1 promoter identified the heme-responsive sequences as the stress-response element (StRE), multiple copies of which are present in two enhancer regions, E1 and E2. Electrophoretic mobility shift assays identified Nrf2, MafG, ATF3, and Jun and Fos family members as StRE-binding proteins; binding of Nrf2, MafG, and ATF3 was increased in response to heme. Dominant-negative mutants of Nrf2 and Maf, but not of c-Fos and c-Jun, inhibited basal and heme-induced expression of an E1-controlled luciferase gene. Heme did not affect the transcription activity of Nrf2, dimerization between Nrf2 and MafG, or the level of MafG, but did stimulate expression of Nrf2. Heme did not influence the level of Nrf2 mRNA but increased the half-life of Nrf2 protein from approximately 10 min to nearly 110 min. These results indicate that heme promotes stabilization of Nrf2, leading to accumulation of Nrf2. MafG dimers that bind to StREs to activate the ho-1 gene.

CFTR and Wnt/beta-catenin signaling in lung development

BACKGROUND

Cystic fibrosis transmembrane conductance regulator (CFTR) was shown previously to modify stretch induced differentiation in the lung. The mechanism for CFTR modulation of lung development was examined by in utero gene transfer of either a sense or antisense construct to alter CFTR expression levels. The BAT-gal transgenic reporter mouse line, expressing beta-galactosidase under a canonical Wnt/beta-catenin-responsive promoter, was used to assess the relative roles of CFTR, Wnt, and parathyroid hormone-related peptide (PTHrP) in lung organogenesis. Adenoviruses containing full-length CFTR, a short anti-sense CFTR gene fragment, or a reporter gene as control were used in an intra-amniotic gene therapy procedure to transiently modify CFTR expression in the fetal lung.

RESULTS

A direct correlation between CFTR expression levels and PTHrP levels was found. An inverse correlation between CFTR and Wnt signaling activities was demonstrated.

CONCLUSION

These data are consistent with CFTR participating in the mechanicosensory process essential to regulate Wnt/beta-Catenin signaling required for lung organogenesis.

Small interfering peptide (siP) for in vivo examination of the developing lung interactonome

To understand the role of reactive oxygen species in mechanosensory control of lung development a new approach to interfere with protein-protein interactions by means of a short interacting peptide was developed. This technology was used in the developing rodent lung to examine the role of NADPH oxidase (NOX), casein kinase 2 (CK2), and the cystic fibrosis transmembrane conductance regulator (CFTR) in stretch-induced differentiation. Interactions between these molecules was targeted in an in utero system with recombinant adeno-associated virus (rAAV) containing inserted DNA sequences that express a control peptide or small interfering peptides (siPs) specific for subunit interaction or phosphorylation predicted to be necessary for multimeric enzyme formation. In all cases only siPs with sequences necessary for a predicted normal function were found to interfere with assembly of the multimeric enzyme. A noninterfering control siP to nonessential regions or reporter genes alone had no effect. Physiologically, it was shown that siPs that interfered with the NOX-CFTR-CK2 complex that we call an "interactonome" affected markers of stretch-induced lung organogenesis including Wnt/beta-catenin signaling.

Transient in utero disruption of cystic fibrosis transmembrane conductance regulator causes phenotypic changes in alveolar type II cells in adult rats

Background

Mechanicosensory mechanisms regulate cell differentiation during lung organogenesis. We have previously demonstrated that cystic fibrosis transmembrane conductance regulator (CFTR) was integral to stretch-induced growth and development and that transient expression of antisense-CFTR (ASCFTR) had negative effects on lung structure and function. In this study, we examined adult alveolar type II (ATII) cell phenotype after transient knock down of CFTR by adenovirus-directed in utero expression of ASCFTR in the fetal lung.

Results

In comparison to (reporter gene-treated) Controls, ASCFTR-treated adult rat lungs showed elevated phosphatidylcholine (PC) levels in the large but not in the small aggregates of alveolar surfactant. The lung mRNA levels for SP-A and SP-B were lower in the ASCFTR rats. The basal PC secretion in ATII cells was similar in the two groups. However, compared to Control ATII cells, the cells in ASCFTR group showed higher PC secretion with ATP or phorbol myristate acetate. The cell PC pool was also larger in the ASCFTR group. Thus, the increased surfactant secretion in ATII cells could cause higher PC levels in large aggregates of surfactant. In freshly isolated ATII cells, the expression of surfactant proteins was unchanged, suggesting that the lungs of ASCFTR rats contained fewer ATII cells. Gene array analysis of RNA of freshly isolated ATII cells from these lungs showed altered expression of several genes including elevated expression of two calcium-related genes, Ca²⁺-ATPase and calcium-calmodulin kinase kinase1 (CaMkk1), which was confirmed by real-time PCR. Western blot analysis showed increased expression of calmodulin kinase I, which is activated following phosphorylation by CaMkk1. Although increased expression of calcium regulating genes would argue in favor of Ca²⁺-dependent mechanisms increasing surfactant secretion, we cannot exclude contribution of alternate mechanisms because of other phenotypic changes in ATII cells of the ASCFTR group.

Conclusion

Developmental changes due to transient disruption of CFTR in fetal lung reflect in altered ATII cell phenotype in the adult life.

Adult onset lung disease following transient disruption of fetal stretch-induced differentiation

One of the mechanisms by which adult disease can arise from a fetal origin is by in utero disruption of organogenesis. These studies were designed to examine respiratory function changes in aging rats following transient disruption of lung growth at 16 days gestation. Fetuses were treated in utero with a replication deficient adenovirus containing the cystic fibrosis conductance transmembrane regulator (CFTR) gene fragment cloned in the anti-sense direction. The in utero-treated rats demonstrated abnormal lung function beginning as early as 30 days of age and the pathology progressed as the animals aged. The pulmonary function abnormalities included decreased static compliance as well as increased conducting airway resistance, tissue damping, and elastance. Pressure volume (PV) curves demonstrated a slower early rise to volume and air trapping at end-expiration. The alterations of pulmonary function correlated with lung structural changes determined by morphometric analysis. These studies demonstrate how transient disruption of lung organogensis by single gene interference can result in progressive change in lung function and structure. They illustrate how an adult onset disease can arise from subtle changes in gene expression during fetal development.

99 ASSESSMENT AND MANAGEMENT OF PAIN IN OLDER ADULTS WITH ACUTE FRACTURE ADMITTED UNDER AN ORTHOPAEDIC SERVICE

Background

Older adults with acute fractures often have suboptimal pain control, in particular those with cognitive impairment. Effective pain management improves rehabilitation engagement and earlier discharge from acute care. Our study aimed to evaluate pain management of older adults with acute fracture admitted under an orthopaedic service in a tertiary hospital.

Methods

Prospective review of patients over 65 years with an acute fracture admitted under an orthopaedic service. Review of chart, medication prescription and pain status. Data included type of fracture, comorbidities, cognitive status and analgesia prescribed. Data analysed using Excel.

Results

40 inpatients included. Median age 82 years (range 65-93 years), 70% female. 53% had cognitive impairment, ranging from mild to severe dementia. 75% had >5 regular medications pre-admission. 80% had >5 comorbidities.

Two-thirds (73%) had an acute hip fracture. Most (80%) inpatients had a surgical intervention, the remaining were managed conservatively.

Analgesia prescriptions included paracetamol for almost all patients (95%), non-steroidal anti-inflammatory drugs for 3 (8%) and regular opioids in only 3 (8%).

43% of patients reported pain at time of data collection. 13% had analgesia changed in the 24 hours beforehand. Pain adversely affected function in 205 and mobility in 28%.

2 patients were unable to verbalise pain however no pain scales or visual assessments were used.

Documentation of pain assessment was best by nurses (100%) followed by doctors (60%) and allied health professionals (40%).

Conclusion

Older adults with acute fracture are often multimorbid with cognitive impairment. This patient population are often untreated for pain with suboptimal pain assessment and analgesia review or prescriptions. Consequently we developed a pain policy for use on our orthopaedic service as a guide for effective pain assessment and management for older adults with acute fracture.

254 OPTIMISING COMMUNICATION WITH FAMILIES OF PATIENTS ON ACUTE STROKE AND GERIATRIC MEDICINE WARDS IN A LARGE TERTIARY HOSPITAL

Background

Good communication with patients and families is important for older adults admitted to acute stroke or geriatric medicine wards, particularly with COVID19-related restricted visiting. These patients often have communication difficulties including aphasia, delirium, cognitive or hearing impairment, limiting their own communication with relatives. Using the Plan, Do, Study, Act (PDSA) approach we undertook a quality improvement project to optimise communication with families of patients on above wards in a large tertiary hospital.

Methods

PDSA cycle 1: Staff were surveyed to identify satisfaction level with communication and ways to optimise communication. Inpatients on study wards were identified, we recorded demographic and clinical details and prevalence of communication difficulties. We created a designated folder with individual ‘communication sheets’ in conjunction with ward doctors and the nurse manager. PDSA cycle 2: We performed a rapid interval audit of the communication folder use. ‘Outlier’ patients were excluded as their teams did not receive education about folder use.

Results

PDSA cycle 1: A total of 90 inpatients on three wards were included, mean age 78y (SD ±14.4y), 47% were male. Three-quarters (73%) had a communication difficulty noted, reported by nursing staff. Two patients were intubated and six had stroke-related aphasia. Half of surveyed staff reported communication with families was suboptimal. Most (86%) suggested a centrally-located communication logbook would be helpful. PDSA cycle 2: Over two weeks, communication sheets were reviewed for all included patients. Median frequency of calls to families was 4 days (range 0–14). Most (79%) had the name of the primary contact clearly documented. Many (52%) included no contact number. Only 9% had secondary contact information documented.

Conclusion

Communication with families of patients on acute stroke and geriatric medicine wards was suboptimal. Over a short interval this improved with regular phone calls using specific centrally-located communication folders. Further optimisation of their use is needed.

154 SAFEGUARDING ADULTS AT RISK OF ABUSE—IDENTIFYING KNOWLEDGE GAPS AMONGST HOSPITAL STAFF TO GUIDE POLICY IMPLEMENTATION AND TRAINING

Background

Safeguarding is the protection of health, wellbeing and life free from abuse. Abuse is a a violation of a person’s human and civil rights; forms include psychological, financial, physical, sexual, neglect and self-neglect. Health Service Executive (HSE) drafted the 2019 ‘Adult Safeguarding Policy’ for adults at risk of abuse to replace the 2014 version. In preparation for implementation a tertiary hospital founded a Safeguarding Committee in 2021. A core objective was establishing staff understanding, experience of safeguarding and education needs to guide future training.

Methods

10-question survey of 223 staff; included doctors, nurses, allied health professionals, medical social workers, healthcare assistants, porters, psychologists.

Results

91% response rate.

184 (91%) staff were familiar with the term ‘safeguarding’; only 44% were aware of the HSE 2019 policy. 129 (64%) had experience with a case of suspected abuse. Most common forms were financial, psychological and self-neglect (n = 60, 47, 39 respectively). Sexual abuse was least common (n = 10).

47% felt ‘somewhat’ confident recognising possible abuse compared to 42% who felt ‘extremely’ or ‘very’ confident.

61% were ‘somewhat’ or ‘not so’ confident about the next steps for suspected abuse; only 11% were ‘extremely’ confident.

49% felt ‘extremely’ or ‘very’ confident in reporting a suspected abuse case; 50% felt ‘somewhat’ or ‘not so’ confident.

Most common reasons for lack of confidence were lack of training, unclear reporting process and lack of experience with cases of abuse. Medical social workers were most confident; doctors were the least.

170 (84%) wanted more safeguarding training—the most popular options were online or in-person training.

Conclusion

Gaps in knowledge and confidence were identified amongst staff for cases of suspected abuse. This will guide future training in the hospital in line with the HSE Adult Safeguarding policy.

744 3 YEAR FOLLOW-UP OF SEDATIVE PRESCRIBING FOR RESPONSIVE BEHAVIOURS IN NURSING HOME RESIDENTS, AN IRISH STUDY

Introduction

Sedative medications are commonly prescribed for older adults; these include neuroleptics, benzodiazepines, opioids, ‘z’ drugs and trazadone. The prevalence of sedative drug prescriptions is increasing (1). Nursing home residents are three times more likely to be prescribed benzodiazepines (2). Regular medication review and education have been shown to reduce rates of sedative use in nursing homes (3). We previously demonstrated a significant reduction in prescription of these target medications at an Irish nursing home with specific focus, within scheduled medication reviews, on reduction or discontinuation of the target drugs in combination with education on management of Behavioural and Psychological symptoms (BPSD). This audit examines the prescribing patterns 3 years on from the initial audit.

Methods

Point prevalence study of sedative prescriptions and BPSD of all 95 nursing home residents on 6/5/21. Comparison with data from two previous audits in the same unit. All data was anonymised. Data analysed with SPSS statistical software.

Results

Sustained significant drop in quetiapine use from 30% of residents to 14% post-intervention in 2018 and three-year follow-up (p = 0.06). Borderline significant reduction in overall neuroleptics (from 39% to 25%, p = 0.06). Significant rise in ‘z’ drug prescription (from 8% to 17%, p = 0.03). BPSD reported in 33%, compared to 49% pre-intervention.

Conclusion

Regularly scheduled medication reviews can effectively rationalise sedative prescription rates in nursing home residents. Increasing ‘z’ drug prescription likely represents the appropriate replacement of neuroleptics. Reduced BPSD may be due to reporting bias of staff since regular education has been introduced or changing cohort of residents. References numbered above not included given limited word count.

Transient in utero nicotine exposure stimulates mechanosensory-dependent lung development

Nicotine receptors are present in the developing lung yet their function is unknown. The transient role of nicotine receptors in lung development has not been addressed. In this study, nicotine's direct effect on smooth muscle contraction, necessary for mechanosensory-dependent fetal lung development, is examined after transient nicotine stimulation to determine the relationship between nicotine exposure, smooth muscle contraction, and fetal lung development. Rat fetuses at 16 days’ gestation were exposed in utero to 5 different concentrations of nicotine or control injected directly into the amniotic fluid. Specific concentrations of in utero nicotine increased the phosphorylated Western blot analysis and immunohistochemistry of muscle contraction proteins. Respiratory function tests on nicotine-exposed rat pups showed a statistically significant decrease in airway resistance earlier in life compared to control and an upward shift of the pressure-volume curve pointing towards a structural maturation of the in utero nicotine-exposed lung. These results are consistent with transient nicotine exposure during intrauterine life stimulating stretch-induced lung organogenesis by altering phosphorylation of muscle contraction proteins. The increase in smooth muscle phosphorylation may stimulate stretch-induced lung organogenesis, which affects lung development and accelerates lung maturation in rats.

98 SCHEDULED MEDICATION REVIEWS AND EDUCATION ON SEDATIVE PRESCRIBING FOR RESPONSIVE BEHAVIOURS IN NURSING HOME RESIDENTS, A 3 YEAR FOLLOW-UP STUDY

Background

Sedative medications including neuroleptics, benzodiazepines, opioids, ‘z’ drugs and trazadone are commonly prescribed for older adults. Nursing home residents are three times more likely to be prescribed benzodiazepines. Sedative medications are associated with significant risks including falls and delirium in older adults. Neuroleptics also increase risk of cerebrovascular disease and functional decline. Regular medication review and education have been shown to reduce rates of sedative use in nursing homes. Scheduled medication reviews were introduced in an Irish nursing home with a specific focus on reduction or discontinuation of these target medications in combination with education of management of Behavioural and Psychological symptoms (BPSD). We demonstrated previously a significant reduction in prescribing following these interventions. This audit examines the prescribing patterns 3 years on from the initial audit.

Methods

Point prevalence study of sedative prescriptions and BPSD on 6/5/21 of all 95 nursing home residents. Data compared with two preceding audits in 2018 in the same unit. All data anonymised. Data analysed with SPSS statistical software.

Results

Significant reduction in quetiapine use sustained from 30% of residents pre-intervention to 14% post-intervention in 2018 and 2021 (p = 0.06).

Neuroleptic prescription reduced from 39% to 25% (p = 0.06).

‘Z’ drug prescribing increased from 8% to 17% (p = 0.03).

33% of residents had BPSD reported compared to 49% pre-intervention.

Conclusion

3 year follow-up showed regularly scheduled medication reviews and education in a nursing home can effectively rationalise sedative prescription rates. Sustained reduction in neuroleptics and increased ‘z’ drug prescriptions may represent appropriate replacement. Reduced BPSD may be due to changing nursing home resident cohort or reporting bias of staff since the introduction of regular education.