1,25-Dihydroxyvitamin D3 Suppresses UV-Induced Poly(ADP-Ribose) Levels in Primary Human Keratinocytes, as Detected by a Novel Whole-Cell ELISA.

Photoprotective properties of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) to reduce UV-induced DNA damage have been established in several studies. UV-induced DNA damage in skin such as single or double strand breaks is known to initiate several cellular mechanisms including activation of poly(ADP-ribose) (pADPr) polymerase-1 (PARP-1). DNA damage from UV also increases extracellular signal-related kinase (ERK) phosphorylation, which further increases PARP activity. PARP-1 functions by using cellular nicotinamide adenine dinucleotide (NAD+) to synthesise pADPr moieties and attach these to target proteins involved in DNA repair. Excessive PARP-1 activation following cellular stress such as UV irradiation may result in excessive levels of cellular pADPr. This can also have deleterious effects on cellular energy levels due to depletion of NAD+ to suboptimal levels. Since our previous work indicated that 1,25(OH)2D3 reduced UV-induced DNA damage in part through increased repair via increased energy availability, the current study investigated the effect of 1,25(OH)2D3 on UV-induced PARP-1 activity using a novel whole-cell enzyme- linked immunosorbent assay (ELISA) which quantified levels of the enzymatic product of PARP-1, pADPr. This whole cell assay used around 5000 cells per replicate measurement, which represents a 200-400-fold decrease in cell requirement compared to current commercial assays that measure in vitro pADPr levels. Using our assay, we observed that UV exposure significantly increased pADPr levels in human keratinocytes, while 1,25(OH)2D3 significantly reduced levels of UV-induced pADPr in primary human keratinocytes to a similar extent as a known PARP-1 inhibitor, 3-aminobenzamide (3AB). Further, both 1,25(OH)2D3 and 3AB as well as a peptide inhibitor of ERK-phosphorylation significantly reduced DNA damage in UV-exposed keratinocytes. The current findings support the proposal that reduction in pADPr levels may be critical for the function of 1,25(OH)2D3 in skin to reduce UV-induced DNA damage.

Barriers and co-designed strategies for the implementation of negative pressure wound therapy in acute pediatric burn care in Australia: A mixed method study.

PURPOSE: Pediatric burn injuries are a global clinical issue causing significant morbidity. Early adjunctive negative pressure wound therapy improves re-epithelialization rates in children with burns, yet adoption in acute burn care is inconsistent. This investigation aimed to determine barriers to the implementation of adjunctive negative pressure wound therapy for the acute management of pediatric burns and co-design targeted implementation strategies. METHODS: A sequential mixed methods design was used explore barriers to adjunctive negative pressure wound therapy implementation in acute pediatric burn care. An online questionnaire was disseminated to healthcare professionals within four major Australian pediatric hospitals, each with a dedicated burns service. Barriers were coded according to the Consolidated Framework for Implementation Research (CFIR). Semi-structured interviews with senior clinicians tailored implementation strategies to local contexts. A stakeholder consensus meeting consolidated implementation strategies and local processes. RESULTS: Sixty-three healthcare professionals participated in the questionnaire, and semi-structured interviews involved nine senior burn clinicians. We identified eight implementation barriers across all five CFIR domains then co-designed targeted strategies to address identified barriers. Barriers included lack of available resources, limited access to knowledge and information, individual stage of change, patient needs and resources, limited knowledge and beliefs about the intervention, lack of external policies, intervention complexity, and poor implementation planning. CONCLUSION: Multiple contextual factors affect negative pressure wound therapy uptake in acute pediatric burn settings. Results will inform a multi-state stepped-wedge cluster randomized controlled trial. Additional resources, education, training, updated policies, and guidelines are required for successful implementation. It is anticipated that adjunctive negative pressure wound therapy, in conjunction with tailored implementation strategies, will enhance adoption and sustainability. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry: ACTRN12622000166774. Registered 1 February 2022.

Inflammatory proteins and neutrophil extracellular traps increase in burn blister fluid 24h after burn.

Burn wound blister fluid is a valuable matrix for understanding the biological pathways associated with burn injury. In this study, 152 blister fluid samples collected from paediatric burn wounds at three different hospitals were analysed using mass spectrometry proteomic techniques. The protein abundance profile at different days after burn indicated more proteins were associated with cellular damage/repair in the first 24 h, whereas after this point more proteins were associated with antimicrobial defence. The inflammatory proteins persisted at a high level in the blister fluid for more than 7 days. This may indicate that removal of burn blisters prior to two days after burn is optimal to prevent excessive or prolonged inflammation in the wound environment. Additionally, many proteins associated with the neutrophil extracellular trap (NET) pathway were increased after burn, further implicating NETs in the post-burn inflammatory response. NET inhibitors may therefore be a potential treatment to reduce post-burn inflammation and coagulation pathology and enhance burn wound healing outcomes.

The Over-Irradiation Metabolite Derivative, 24-Hydroxylumister-ol3, Reduces UV-Induced Damage in Skin.

The hormonal form of vitamin D3, 1,25(OH)2D3, reduces UV-induced DNA damage. UV exposure initiates pre-vitamin D3 production in the skin, and continued UV exposure photoisomerizes pre-vitamin D3 to produce "over-irradiation products" such as lumisterol3 (L3). Cytochrome P450 side-chain cleavage enzyme (CYP11A1) in skin catalyzes the conversion of L3 to produce three main derivatives: 24-hydroxy-L3 [24(OH)L3], 22-hydroxy-L3 [22(OH)L3], and 20,22-dihydroxy-L3 [20,22(OH)L3]. The current study investigated the photoprotective properties of the major over-irradiation metabolite, 24(OH)L3, in human primary keratinocytes and human skin explants. The results indicated that treatment immediately after UV with either 24(OH)L3 or 1,25(OH)2D3 reduced UV-induced cyclobutane pyrimidine dimers and oxidative DNA damage, with similar concentration response curves in keratinocytes, although in skin explants, 1,25(OH)2D3 was more potent. The reductions in DNA damage by both compounds were, at least in part, the result of increased DNA repair through increased energy availability via increased glycolysis, as well as increased DNA damage recognition proteins in the nucleotide excision repair pathway. Reductions in UV-induced DNA photolesions by either compound occurred in the presence of lower reactive oxygen species. The results indicated that under in vitro and ex vivo conditions, 24(OH)L3 provided photoprotection against UV damage similar to that of 1,25(OH)2D3.

Impact of childhood burns on academic performance: a matched population-based cohort study.

OBJECTIVE: This study aimed to compare academic performance and high school completion of young people hospitalised for a burn compared with young people not hospitalised for an injury. DESIGN: A retrospective population-based matched case-comparison cohort study. PARTICIPANTS: Young people aged ≤18 years hospitalised for a burn during 2005-2018 in New South Wales, Australia, with age, sex and residential postcode-matched peers not hospitalised for any injury during 1 July 2001 and 31 December 2018. MAIN OUTCOME MEASURES: Performance below the national minimum standard (NMS) on the National Assessment Plan for Literacy and Numeracy assessments and not completing high school. RESULTS: Young females hospitalised for a burn had a 72% higher risk of poorer reading compared with their peers (adjusted relative risk (ARR) 1.72; 95% CI 1.33 to 2.23), while young males hospitalised with a burn showed no higher risk (ARR 1.14; 95% CI 0.91 to 1.43). Young males (ARR 1.05; 95% CI 0.81 to 1.35) and females (ARR 1.34; 95% CI 0.93 to 1.94) hospitalised with a burn had no higher risk of not reaching the NMS for numeracy compared with peers. Young people hospitalised with a burn had at least twice the risk of not completing year 10 (ARR 3.86; 95% CI 1.68 to 8.86), year 11 (ARR 2.45; 95% CI 1.89 to 3.18) and year 12 (ARR 2.09; 95% CI 1.63 to 2.67) compared with matched counterparts. CONCLUSIONS: Young females hospitalised with a burn displayed poorer academic performance for reading compared with matched peers, while males and females were more likely to leave school earlier. Identifying unmet learning support needs of young burn survivors should be investigated.

Discharge interventions for First Nations people with a chronic condition or injury: a systematic review.

BACKGROUND: Aboriginal and Torres Strait Islander peoples have a unique place in Australia as the original inhabitants of the land. Similar to other First Nations people globally, they experience a disproportionate burden of injury and chronic health conditions. Discharge planning ensures ongoing care to avoid complications and achieve better health outcomes. Analysing discharge interventions that have been implemented and evaluated globally for First Nations people with an injury or chronic conditions can inform the implementation of strategies to ensure optimal ongoing care for Aboriginal and Torres Strait Islander people. METHODS: A systematic review was conducted to analyse discharge interventions conducted globally among First Nations people who sustained an injury or suffered from a chronic condition. We included documents published in English between January 2010 and July 2022. We followed the reporting guidelines and criteria set in Preferred Reporting Items for Systematic Review (PRISMA). Two independent reviewers screened the articles and extracted data from eligible papers. A quality appraisal of the studies was conducted using the Mixed Methods Appraisal Tool and the CONSIDER statement. RESULTS: Four quantitative and one qualitative study out of 4504 records met inclusion criteria. Three studies used interventions involving trained health professionals coordinating follow-up appointments, linkage with community care services and patient training. One study used 48-hour post discharge telephone follow-up and the other text messages with prompts to attend check-ups. The studies that included health professional coordination of follow-up, linkage with community care and patient education resulted in decreased readmissions, emergency presentations, hospital length of stay and unattended appointments. CONCLUSION: Further research on the field is needed to inform the design and delivery of effective programs to ensure quality health aftercare for First Nations people. We observed that discharge interventions in line with the principal domains of First Nations models of care including First Nations health workforce, accessible health services, holistic care, and self-determination were associated with better health outcomes. REGISTRATION: This study was prospectively registered in PROSPERO (ID CRD42021254718).

Codesigning informative resources for families of Aboriginal and Torres Strait Islander children who sustained a burn injury: a protocol for a participatory action research study.

INTRODUCTION: Parents of children hospitalised in a burn unit experience psychological trauma and later post-traumatic stress. Aboriginal and Torres Strait Islander families whose child has been admitted to a burn unit encounter additional burdens through a culturally unsafe healthcare system. Psychosocial interventions can help reduce anxiety, distress and trauma among children and parents. There remains a lack of interventions or resources that reflect Aboriginal and Torres Strait Islander people's perspective of health. The objective of this study is to codevelop a culturally appropriate informative resource to assist Aboriginal and Torres Strait Islander parents whose child has been hospitalised in a burn unit. METHODS: In this participatory research study, the development of a culturally safe resource will build on Aboriginal and Torres Strait Islander families' experiences and voices, complemented by the knowledge and expertise of an Aboriginal Health Worker (AHW) and burn care experts. Data will be collected through recorded yarning sessions with families whose child has been admitted to a burn unit, the AHW and burn care experts. Audiotapes will be transcribed and data will be analysed thematically. Analysis of yarning sessions and resource development will follow a cyclical approach. ETHICS AND DISSEMINATION: This study has been approved by the Aboriginal Health and Medical Research Council (AH&MRC) (1690/20) and the Sydney Children's Hospitals Network ethics committee (2020/ETH02103). Findings will be reported to all participants and will be disseminated with the broader community, the funding body and health workers at the hospital. Dissemination with the academic community will be through peer-reviewed publications and presentations in relevant conferences.

Playground injury prevention: the need for consistent and national implementation of Australian safety standards.

OBJECTIVES: Hospitalisation rates for injury, including at playgrounds, have not changed in the past decade. There are nine Australian Standards specific to playgrounds. The impact (if any) of these standards on playground injury resulting in hospitalisation is unknown. METHODS: Retrospective data for patients under 18 years presenting to emergency departments and/or admitted between October 2015 and December 2019 due to an injury documented as occurring at a playground were retrieved by the Illawarra Shoalhaven Local Health District Planning, Information and Performance Department. Maintenance and Australian Standard (AS) compliance data for the 401 local playgrounds were requested from the four Local Governments in Illawarra Shoalhaven Local Health District. Descriptive statistics were used. RESULTS: A total of 548 children were treated in emergency departments and/or admitted following playground injury. There was an overall increase of 39.3% in playground injury across the study period, and expenditure rose from $43,478 in 2011 to $367,259 in 2019 (a 744.7% increase). CONCLUSIONS: Playground injury has not decreased in the Illawarra Shoalhaven. Data regarding maintenance and AS compliance are lacking. This is not unique to our region. IMPLICATIONS FOR PUBLIC HEALTH: Without a national approach to adequately resource and monitor playground injury, it is not possible to assess the impact of Australian Standards or any injury prevention program.

The CaSR Modulator NPS-2143 Reduced UV-Induced DNA Damage in Skh:hr1 Hairless Mice but Minimally Inhibited Skin Tumours.

The calcium-sensing receptor (CaSR) is an important regulator of epidermal function. We previously reported that knockdown of the CaSR or treatment with its negative allosteric modulator, NPS-2143, significantly reduced UV-induced DNA damage, a key factor in skin cancer development. We subsequently wanted to test whether topical NPS-2143 could also reduce UV-DNA damage, immune suppression, or skin tumour development in mice. In this study, topical application of NPS-2143 (228 or 2280 pmol/cm2) to Skh:hr1 female mice reduced UV-induced cyclobutane pyrimidine dimers (CPD) (p < 0.05) and oxidative DNA damage (8-OHdG) (p < 0.05) to a similar extent as the known photoprotective agent 1,25(OH)2 vitamin D3 (calcitriol, 1,25D). Topical NPS-2143 failed to rescue UV-induced immunosuppression in a contact hypersensitivity study. In a chronic UV photocarcinogenesis protocol, topical NPS-2143 reduced squamous cell carcinomas for only up to 24 weeks (p < 0.02) but had no other effect on skin tumour development. In human keratinocytes, 1,25D, which protected mice from UV-induced skin tumours, significantly reduced UV-upregulated p-CREB expression (p < 0.01), a potential early anti-tumour marker, while NPS-2143 had no effect. This result, together with the failure to reduce UV-induced immunosuppression, may explain why the reduction in UV-DNA damage in mice with NPS-2143 was not sufficient to inhibit skin tumour formation.

Patient journey mapping to investigate quality and cultural safety in burn care for Aboriginal and Torres Strait Islander children and families - development, application and implications.

BACKGROUND: Quality and safety in Australian healthcare is inequitably distributed, highlighted by gaps in the provision of quality care for Aboriginal and Torres Strait Islander children. Burns have potential for long-term adverse outcomes, and quality care, including culturally safe care, is critical to recovery. This study aimed to develop and apply an Aboriginal Patient Journey Mapping (APJM) tool to investigate the quality of healthcare systems for burn care with Aboriginal and Torres Strait Islander children. STUDY DESIGN: Interface research methodology, using biomedical and cultural evidence, informed the modification of an existing APJM tool. The tool was then applied to the journey of one family accessing a paediatric tertiary burn care site. Data were collected through yarning with the family, case note review and clinician interviews. Data were analysed using Emden's core story and thematic analysis methods. Reflexivity informed consideration of the implications of the APJM tool, including its effectiveness and efficiency in eliciting information about quality and cultural safety. RESULTS: Through application of a modified APJM tool, gaps in quality care for Aboriginal and Torres Strait Islander children and families were identified at the individual, service and system levels. Engagement in innovative methodology incorporating more than biomedical standards of care, uncovered critical information about the experiences of culturally safe care in complex patient journeys. CONCLUSION: Based on our application of the tool, APJM can identify and evaluate specific aspects of culturally safe care as experienced by Aboriginal and Torres Strait Islander peoples and be used for quality improvement.

Discharge Interventions for First Nations People with Injury or Chronic Conditions: A Protocol for a Systematic Review.

Severe injury and chronic conditions require long-term management by multidisciplinary teams. Appropriate discharge planning ensures ongoing care to mitigate the long-term impact of injuries and chronic conditions. However, First Nations peoples in Australia face ongoing barriers to aftercare. This systematic review will locate and analyse global evidence of discharge interventions that have been implemented to improve aftercare and enhance health outcomes among First Nations people with an injury or chronic condition. A systematic search will be conducted using five databases, Google, and Google scholar. Global studies published in English will be included. We will analyse aftercare interventions implemented and the health outcomes associated. Two independent reviewers will screen and select studies and then extract and analyse the data. Quality appraisal of the included studies will be conducted using the Mixed Methods Appraisal Tool and the CONSIDER statement. The proposed study will analyse global evidence on discharge interventions that have been implemented for First Nations people with an injury or chronic conditions and their associated health outcomes. Our findings will guide healthcare quality improvement to ensure Aboriginal and Torres Strait Islander peoples have ongoing access to culturally safe aftercare services.

Paediatric pelvic fractures - an updated literature review.

BACKGROUND: Pelvic fractures in children are indicative of significant trauma. Patients will often have associated injuries - some of which require urgent intervention to prevent death and disability. Paediatric and adult pelvises respond to traumatic forces differently and distinct approaches are required for each population. Historically, pelvic fractures have been treated conservatively, but this trend is changing with a better understanding of the pelvis' inability to remodel significant deformity, as well as new techniques for operative fixation. METHODS: A comprehensive search of the literature was conducted for articles published between 2000 and 2020 on paediatric pelvic fractures using medical databases including PubMed, Embase and the Cochrane Library. RESULTS: We included 143 studies in our literature review and summarized the incidence, pathophysiology, assessment, management and complications associated with paediatric pelvic fractures. CONCLUSIONS: The rarity of paediatric pelvic fractures corresponds with a paucity of randomized clinical trials covering this topic. Trends such as the screening pelvic x-ray are derived from adult populations but are now questioned in children. Other aspects of assessment and management of these children warrant such levels of scrutiny.

Systemic long-term metabolic effects of acute non-severe paediatric burn injury.

A growing body of evidence supports the concept of a systemic response to non-severe thermal trauma. This provokes an immunosuppressed state that predisposes paediatric patients to poor recovery and increased risk of secondary morbidity. In this study, to understand the long-term systemic effects of non-severe burns in children, targeted mass spectrometry assays for biogenic amines and tryptophan metabolites were performed on plasma collected from child burn patients at least three years post injury and compared to age and sex matched non-burn (healthy) controls. A panel of 12 metabolites, including urea cycle intermediates, aromatic amino acids and quinolinic acid were present in significantly higher concentrations in children with previous burn injury. Correlation analysis of metabolite levels to previously measured cytokine levels indicated the presence of multiple cytokine-metabolite associations in the burn injury participants that were absent from the healthy controls. These data suggest that there is a sustained immunometabolic imprint of non-severe burn trauma, potentially linked to long-term immune changes that may contribute to the poor long-term health outcomes observed in children after burn injury.

Paediatric intestinal pseudo-obstruction: a scoping review.

Paediatric intestinal pseudo-obstruction (PIPO) encompasses a group of rare disorders in which patients present with the clinical features of bowel obstruction in the absence of mechanical occlusion. The management of PIPO presents a challenge as evidence remains limited on available medical and surgical therapy. Parenteral nutrition is often the mainstay of therapy. Long-term therapy may culminate in life-threatening complications including intestinal failure-related liver disease, central line thrombosis and sepsis. Intestinal transplantation remains the only definitive cure in PIPO but is a complex and resource-limited solution associated with its own morbidity and mortality. We conducted a scoping review to present a contemporary summary of the epidemiology, aetiology, pathophysiology, diagnosis, management and complications of PIPO.Conclusion: PIPO represents a rare disorder that is difficult to diagnose and challenging to treat, with significant morbitity and mortality. The only known cure is intestinal transplantation. What is Known: • Paediatric intestinal pseudo-obstruction is a rare, heterogeneous disorder that confers a high rate of morbidity and mortality • Complications of paediatric intestinal pseudo-obstruction include chronic pain, small intestine bacterial overgrowth and malrotation. Other complications can occur related to its management, such as line infections with parenteral nutrition or cardiac side effects of prokinetic medications What is New: • Progress in medical and surgical therapy in recent years has led to improved patient outcomes • Enteral autonomy has been reported in most patients at as early as 1 month post-transplantation.

UV-induced DNA Damage in Skin is Reduced by CaSR Inhibition.

The epidermis maintains a cellular calcium gradient that supports keratinocyte differentiation from its basal layers (low) to outer layers (high) leading to the development of the stratum corneum, which resists penetration of UV radiation. The calcium-sensing receptor (CaSR) expressed in keratinocytes responds to the calcium gradient with signals that promote differentiation. In this study, we investigated whether the CaSR is involved more directly in protection from UV damage in studies of human keratinocytes in primary culture and in mouse skin studied in vivo. siRNA-directed reductions in CaSR protein levels in human keratinocytes significantly reduced UV-induced direct cyclobutane pyrimidine dimers (CPD) by ~80% and oxidative DNA damage (8-OHdG) by ~65% compared with control transfected cells. Similarly, in untransfected cells, the CaSR negative modulator, NPS-2143 (500 nm), reduced UV-induced CPD and 8-OHdG by ~70%. NPS-2143 also enhanced DNA repair and reduced reactive oxygen species (ROS) by ~35% in UV-exposed keratinocytes, consistent with reduced DNA damage after UV exposure. Topical application of NPS-2143 also protected hairless Skh:hr1 mice from UV-induced CPD, oxidative DNA damage and inflammation, similar to the reductions observed in response to the well-known photoprotection agent 1,25(OH)2 D3 (calcitriol). Thus, negative modulators of the CaSR offer a new approach to reducing UV-induced skin damage.

Management of non-severe burn wounds in children and adolescents: optimising outcomes through all stages of the patient journey.

Paediatric burn injuries are common, especially in children younger than 5 years, and can lead to poor physical and psychosocial outcomes in the long term. In this Review, we aim to summarise the key factors and interventions before hospital admission and following discharge that can improve the long-term outcomes of paediatric burns. Care can be optimised through first aid treatment, correct initial assessment of burn severity, and appropriate patient referral to a burns centre. Scar prevention or treatment and patient follow-up after discharge are also essential. As most burn injuries in children are comparatively small and readily survivable, this Review does not cover the perioperative management associated with severe burns that require fluid resuscitation, or inhalational injury. Burns disproportionately affect children from low socioeconomic backgrounds and those living in low-income and middle-income countries, with ample evidence to suggest that there remains scope for low-cost interventions to improve care for those patients with the greatest burden of burn injury. Current knowledge gaps and future research directions are discussed.

Review of the requirements for effective mass casualty preparedness for trauma systems. A disaster waiting to happen?

Mass casualty incidents (MCIs) are diverse, unpredictable, and increasing in frequency, but preparation is possible and necessary. The nature of MCIs requires a trauma response but also requires effective and tested disaster preparedness planning. From an international perspective, the aims of this narrative review are to describe the key components necessary for optimisation of trauma system preparedness for MCIs, whether trauma systems and centres meet these components and areas for improvement of trauma system response. Many of the principles necessary for response to MCIs are embedded in trauma system design and trauma centre function. These include robust communication networks, established triage systems, and capacity to secure centres from threats to safety and quality of care. However, evidence from the current literature indicates the need to strengthen trauma system preparedness for MCIs through greater trauma leader representation at all levels of disaster preparedness planning, enhanced training of staff and simulated disaster training, expanded surge capacity planning, improved staff management and support during the MCI and in the post-disaster recovery phase, clear provision for the treatment of paediatric patients in disaster plans, and diversified and pre-agreed systems for essential supplies and services continuity. Mass casualty preparedness is a complex, iterative process that requires an integrated, multidisciplinary, and tiered approach. Through effective preparedness planning, trauma systems should be well-placed to deliver an optimal response when faced with MCIs.

Local burn wound environment versus systemic response: Comparison of proteins and metabolites.

In this study, paired blood plasma (BP) and blister fluid (BF) samples from five paediatric burn patients were analysed using mass spectrometry to compare their protein and metabolite composition. The relative quantification of proteins was achieved through a label-free data independent acquisition mode. The relative quantification of metabolites was achieved using a Shimadzu Smart Metabolite Database gas chromatography mass spectrometry (GCMS) targeted assay. In total, 562 proteins and 141 individual metabolites were identified in the samples. There was 81% similarity in the proteins present in the BP and BF, with 50 and 54 unique proteins found in each sample type respectively. BF contained keratinocyte proliferation-related proteins and blood plasma contained abundant blood clotting proteins and apolipoproteins. BF contained more carbohydrates and less alpha-hydroxy acid metabolites than the BP. In this study, there were unique proteins and metabolites in BF and BP which were reflective of the local wound environment and systemic environments respectively. The results from this study demonstrate that the biomolecule content of BF is mostly the same as blood, but it also contains information specific to the local wound environment.

Evidence for Involvement of Nonclassical Pathways in the Protection From UV-Induced DNA Damage by Vitamin D-Related Compounds.

The vitamin D hormone, 1,25dihydroxyvitamin D3 (1,25(OH)2D3), and related compounds derived from vitamin D3 or lumisterol as a result of metabolism via the enzyme CYP11A1, have been shown, when applied 24 hours before or immediately after UV irradiation, to protect human skin cells and skin from DNA damage due to UV exposure, by reducing both cyclobutane pyrimidine dimers (CPD) and oxidative damage in the form of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-OHdG). We now report that knockdown of either the vitamin D receptor or the endoplasmic reticulum protein ERp57 by small, interfering RNA (siRNA) abolished the reductions in UV-induced DNA damage with 20-hydroxyvitamin D3 or 24-hydroxylumisterol3, as previously shown for 1,25(OH)2D3. Treatment with 1,25(OH)2D3 reduced oxygen consumption rates in UV-exposed and sham-exposed human keratinocytes and reduced phosphorylation of cyclic AMP response binding element protein (CREB). Both these actions have been shown to inhibit skin carcinogenesis after chronic UV exposure, consistent with the anticarcinogenic activity of 1,25(OH)2D3. The requirement for a vitamin D receptor for the photoprotective actions of 1,25(OH)2D3 and of naturally occurring CYP11A1-derived vitamin D-related compounds may explain why mice lacking the vitamin D receptor in skin are more susceptible to UV-induced skin cancers, whereas mice lacking the 1α-hydroxylase and thus unable to make 1,25(OH)2D3 are not more susceptible. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.