Seasonal light hours modulate peripheral clocks and energy metabolism in mice

Immune-related adverse events in a nationwide cohort of real-world melanoma patients treated with adjuvant anti-PD1 - Seasonal variation and association with outcome

INTRODUCTION

Immune checkpoint inhibitors (ICIs) carry the risk of immune-related adverse events (irAEs), a significant concern as therapy has transitioned to the adjuvant setting. Balancing therapeutic benefits against potential risks is crucial, necessitating real-world data from an unselected patient population in addition to clinical trial data to ensure optimal clinical decision-making.

METHODS

This nationwide real-world study assessed irAEs in patients receiving adjuvant anti-PD1 therapy, primarily nivolumab, for resected stage III-IV melanoma between 2018-2022. Data were retrieved from two national databases: the IMMUNOTOX database and the Danish Metastatic Melanoma Database (DAMMED). IrAEs were sub-grouped according to organ systems graded using CTCAE ver. 5.0 ranging from mild toxicities (grade 1-2) to severe (grade 3-4) and fatal (grade 5).

RESULTS

Among 792 included patients, (55 % male, median age 62 years (range 16-88)), 697 patients (88 %) experienced an irAE. Severe irAEs occurred in 116 patients (15 %) and five (0.6 %) died due to toxicity. A landmark analysis showed that patients who experienced at least one irAE before the 1st evaluation at 90 days had an increased progression free survival (PFS) (p = 0.032) and overall survival (OS) (p = 0.0071). Additionally, a seasonal pattern was noted with higher incidence of irAEs during summer.

CONCLUSION

The prevalence of irAEs in real-world patients is comparable to the observed risk in clinical trials. Patients experiencing irAEs demonstrate a lower risk of melanoma relapse. Further, gender, age and seasonal variation may impact the incidence of irAEs.

Timing of acute cold exposure determines UCP1 and FGF21 expression - Possible interactions between the thermal environment, thermoregulatory responses, and peripheral clocks

Thermoregulation is synchronized across the circadian cycle to uphold thermal homeostasis. To test if time-of-day matters for the response to environmental cold exposure, mice were acclimated to thermoneutrality (27 °C) for 2 months were subjected acutely (8 h) to cold ambient conditions (15 °C), whereas controls were maintained at thermoneutral conditions. The thermal exposure was tested in separate groups (N = 8) at three distinct time-of-day periods: in the LIGHT phase (L); the DARK phase (D); and a mix of the two (D + L). The magnitude of UCP1 protein and mRNA induction in brown adipose tissue (BAT) in response to acute cold exposure was time-of-day sensitive, peaking in LIGHT, whereas lower induction levels were observed in D + L, and DARK. Plasma levels of FGF21 were induced 3-fold by acute cold exposure at LIGHT and D + L, compared to the time-matched thermoneutral controls, whereas cold in DARK did not cause a significant increase of FGF21 plasma levels. Cold exposure affected, in BAT, the temporal mRNA expression patterns of core circadian clock components: Bmal1, Clock, Per1, Per3, Cry1, Cry2 Nr1d1, and Nr1d2, but in the liver, none of the transcripts were modified. Behavioral assessment using the Thermal Gradient Test (TGT) showed that acute cold exposure reduced cold sensitivity in D + L, but not in DARK. RNA-seq analyses of somatosensory neurons in DRG highlighted the role of the core circadian components in these cells, as well as transcriptional changes due to acute cold exposure. This elucidates the sensory system as a gauge and potential regulator of thermoregulatory responses based on circadian physiology. In conclusion, acute cold exposure elicits time-of-day specific effects on thermoregulatory pathways, which may involve underlying changes in thermal perception. These results have implications for efforts aimed at reducing risks associated with the organization of shift work in cold environments.

Biological clock regulation by the PER gene family: a new perspective on tumor development

The Period (PER) gene family is one of the core components of the circadian clock, with substantial correlations between the PER genes and cancers identified in extensive researches. Abnormal mutations in PER genes can influence cell function, metabolic activity, immunity, and therapy responses, thereby promoting the initiation and development of cancers. This ultimately results in unequal cancers progression and prognosis in patients. This leads to variable cancer progression and prognosis among patients. In-depth studies on the interactions between the PER genes and cancers can reveal novel strategies for cancer detection and treatment. In this review, we aim to provide a comprehensive overview of the latest research on the role of the PER gene family in cancer.

Photoperiod and metabolic health: evidence, mechanism, and implications

Circadian rhythms are evolutionarily programmed biological rhythms that are primarily entrained by the light cycle. Disruption of circadian rhythms is an important risk factor for several metabolic disorders. Photoperiod is defined as total duration of light exposure in a day. With the extended use of indoor/outdoor light, smartphones, television, computers, and social jetlag people are exposed to excessive artificial light at night increasing their photoperiod. Importantly long photoperiod is not limited to any geographical region, season, age, or socioeconomic group, it is pervasive. Long photoperiod is an established disrupter of the circadian rhythm and can induce a range of chronic health conditions including adiposity, altered hormonal signaling and metabolism, premature ageing, and poor psychological health. This review discusses the impact of exposure to long photoperiod on circadian rhythms, metabolic and mental health, hormonal signaling, and ageing and provides a perspective on possible preventive and therapeutic approaches for this pervasive challenge.

Hepatic Vagal Afferents Convey Clock-Dependent Signals to Regulate Circadian Food Intake

Circadian desynchrony induced by shiftwork or jetlag is detrimental to metabolic health, but how synchronous/desynchronous signals are transmitted among tissues is unknown. Here we report that liver molecular clock dysfunction is signaled to the brain via the hepatic vagal afferent nerve (HVAN), leading to altered food intake patterns that are corrected by ablation of the HVAN. Hepatic branch vagotomy also prevents food intake disruptions induced by high-fat diet feeding and reduces body weight gain. Our findings reveal a previously unrecognized homeostatic feedback signal that relies on synchrony between the liver and the brain to control circadian food intake patterns. This identifies the hepatic vagus nerve as a therapeutic target for obesity in the setting of chrono-disruption.

One Sentence Summary

The hepatic vagal afferent nerve signals internal circadian desynchrony between the brain and liver to induce maladaptive food intake patterns.