Age-related upregulation of dense core vesicles in the central inferior colliculus.

Presbycusis is one of the most prevalent disabilities in aged populations of industrialized countries. As we age less excitation reaches the central auditory system from the periphery. To compensate, the central auditory system [e.g., the inferior colliculus (IC)], downregulates GABAergic inhibition to maintain homeostatic balance. However, the continued downregulation of GABA in the IC causes a disruption in temporal precision related to presbycusis. Many studies of age-related changes to neurotransmission in the IC have therefore focused on GABAergic systems. However, we have discovered that dense core vesicles (DCVs) are significantly upregulated with age in the IC. DCVs can carry neuropeptides, co-transmitters, neurotrophic factors, and proteins destined for the presynaptic zone to participate in synaptogenesis. We used immuno transmission electron microscopy across four age groups (3-month; 19-month; 24-month; and 28-month) of Fisher Brown Norway rats to examine the ultrastructure of DCVs in the IC. Tissue was stained post-embedding for GABA immunoreactivity. DCVs were characterized by diameter and by the neurochemical profile (GABAergic/non-GABAergic) of their location (bouton, axon, soma, and dendrite). Our data was collected across the dorsolateral to ventromedial axis of the central IC. After quantification, we had three primary findings. First, the age-related increase of DCVs occurred most robustly in non-GABAergic dendrites in the middle and low frequency regions of the central IC during middle age. Second, the likelihood of a bouton having more than one DCV increased with age. Lastly, although there was an age-related loss of terminals throughout the IC, the proportion of terminals that contained at least one DCV did not decline. We interpret this finding to mean that terminals carrying proteins packaged in DCVs are spared with age. Several recent studies have demonstrated a role for neuropeptides in the IC in defining cell types and regulating inhibitory and excitatory neurotransmission. Given the age-related increase of DCVs in the IC, it will be critical that future studies determine whether (1) specific neuropeptides are altered with age in the IC and (2) if these neuropeptides contribute to the loss of inhibition and/or increase of excitability that occurs during presbycusis and tinnitus.

Increasing physical activity among older adults with gynecologic cancers: a qualitative study.

PURPOSE: The purpose of this study was to gain an understanding of older gynecologic cancer patients' preferences and opinions related to physical activity during chemotherapy, including interventions to promote physical activity. METHODS: Gynecologic cancer patients 60 years or older receiving chemotherapy at a single institution within the last 12 months completed questionnaires and a semi-structured interview asking about their preferences for physical activity interventions aimed at promoting physical activity while receiving treatment. RESULTS: Among the 30 gynecologic cancer patients surveyed and interviewed, a majority agreed with the potential usefulness of a physical activity intervention during chemotherapy (67%) and most reported they would be willing to use an activity tracker during chemotherapy (73%). They expressed a preference for an aerobic activity intervention such as walking, indicated a desire for education from their clinical team on the effects physical activity can have on treatment symptoms, and stated a need for an intervention that could be accessed from anywhere and anytime. Additionally, they emphasized a need for an intervention that considered their treatment symptoms as these were a significant barrier to physical activity while on chemotherapy. CONCLUSION: In this study of older gynecologic cancer patients receiving chemotherapy, most were open to participating in a virtually accessible and symptom-tailored physical activity intervention to promote physical activity during chemotherapy.

Low serum creatinine levels are associated with major post-operative complications in patients undergoing surgery with gynecologic oncologists.

OBJECTIVE: Serum creatinine is a byproduct of muscle metabolism, and low creatinine is postulated to be associated with diminished muscle mass. This study examined the association between low pre-operative serum creatinine and post-operative outcomes. METHODS: This retrospective cohort study utilized the 2014-2021 National Surgical Quality Improvement Program to identify patients undergoing surgery with gynecologic oncologists. Patients with missing pre-operative creatinine, end-stage renal disease, sepsis, septic shock, dialysis, or pregnancy were excluded. Pre-operative creatinine was categorized into markedly low (≤0.44 mg/dL), mildly low (0.45-0.64 mg/dL), normal (0.65-0.84 mg/dL), and four categories of elevated levels (0.85-1.04, 1.05-1.24, 1.25-1.44, and ≥1.45 mg/dL). Outcomes included major (≥Grade 3) 30-day complications, categorized into any complications, wound, cardiovascular and pulmonary, renal, infectious, and thromboembolic complications. Also examined were 30-day readmissions, reoperations, and mortality. Logistic regressions assessed the association between creatinine and complications, with stratification by albumin and sensitivity analysis with propensity score matching. RESULTS: Among 84 786 patients, 0.8% had markedly low, 19.6% mildly low, and 50.2% normal creatinine; the remainder had elevated creatinine. As creatinine decreased, the risks of major complications increased in a dose-dependent manner on univariable and multivariable analyses. A total of 9.6% (n=63) markedly low patients experienced major complications, second to creatinine ≥1.45 mg/dL (9.9%, n=141). On multivariable models, both markedly and mildly low creatinine were associated with higher odds of major complications (OR 1.715, 95% CI 1.299 to 2.264 and OR 1.093, 95% CI 1.001 to 1.193) and infections (OR 1.575, 95% CI 1.118 to 2.218 and OR 1.165, 95% CI 1.048 to 1.296) versus normal. Markedly low creatinine had similar ORs to creatinine ≥1.45 mg/dL and was further associated with higher odds of cardiovascular and pulmonary complications (OR 2.301, 95% CI 1.300 to 4.071), readmissions (OR 1.403, 95% CI 1.045 to 1.884), and mortality (OR 2.718, 95% CI 1.050 to 7.031). After albumin stratification, associations persisted for markedly low creatinine. Propensity-weighted analyses demonstrated congruent findings. CONCLUSIONS: Low creatinine levels are associated with major post-operative complications in gynecologic oncology in a dose-dependent manner. Low creatinine can offer useful information for pre-operative risk stratification, surgical counseling, and peri-operative management.

The activity advantage: Objective measurement of preoperative activity is associated with postoperative recovery and outcomes in patients undergoing surgery with gynecologic oncologists.

OBJECTIVE: To examine the association between objectively-measured preoperative physical activity with postoperative outcomes and recovery milestones in patients undergoing gynecologic oncology surgeries. METHODS: Prospective cohort study of patients undergoing surgery with gynecologic oncologists who wore wearable actigraphy rings before and after surgery from 03/2021-11/2023. Exposures encompassed preoperative activity intensity (moderate- and vigorous-intensity metabolic equivalent of task-minutes [MAVI MET-mins] over seven days) and level (average daily steps over seven days). Intensity was categorized as <500, 500-1000, and >1000 MAVI MET-mins; level categorized as <8000 and ≥8000 steps/day. Primary outcome was 30-day complications. Secondary outcomes included reaching postoperative goal (≥70% of recommended preoperative intensity and level thresholds) and return to baseline (≥70% of individual preoperative intensity and level). RESULTS: Among 96 enrolled, 87 met inclusion criteria, which constituted 39% (n = 34) with <500 MET-mins and 56.3% (n = 49) with <8000 steps preoperatively. Those with <500 MET-mins and <8000 steps had higher ECOG scores (p = 0.042 & 0.037) and BMI (p = 0.049 & 0.002) vs those with higher activity; all other perioperative characteristics were similar between groups. Overall, 29.9% experienced a 30-day complication, 29.9% reached postoperative goal, and 64.4% returned to baseline. On multivariable models, higher activity was associated with lower odds of complications: 500-1000 MET-mins (OR = 0.26,95%CI = 0.07-0.92) and >1000 MET-mins (OR = 0.25,95%CI = 0.07-0.94) vs <500 MET-mins; ≥8000 steps (OR = 0.25,95%CI = 0.08-0.73) vs <8000 steps. Higher preoperative activity was associated fewer days to reach postoperative goal. CONCLUSION: Patients with high preoperative activity are associated with fewer postoperative complications and faster attainment of recovery milestones. Physical activity may be considered a modifiable risk factor for adverse postoperative outcomes.

Low-Density Lipoproteins Increase Proliferation, Invasion, and Chemoresistance via an Exosome Autocrine Mechanism in MDA-MB-231 Chemoresistant Cells.

Dyslipidemias involving high concentrations of low-density lipoproteins (LDLs) increase the risk of developing triple-negative breast cancer (TNBC), wherein cholesterol metabolism and protein translation initiation mechanisms have been linked with chemoresistance. Doxorubicin (Dox) treatment, a member of the anthracycline family, represents a typical therapeutic strategy; however, chemoresistance remains a significant challenge. Exosomes (Exs) secreted by tumoral cells have been implicated in cell communication pathways and chemoresistance mechanisms; the content of exosomes is an outcome of cellular cholesterol metabolism. We previously induced Dox resistance in TNBC cell models, characterizing a variant denominated as variant B cells. Our results suggest that LDL internalization in parental and chemoresistant variant B cells is associated with increased cell proliferation, migration, invasion, and spheroid growth. We identified the role of eIF4F translation initiation factor and the down-regulation of tumor suppressor gene PDCD4, an inhibitor of eIF4A, in chemoresistant variant B cells. In addition, the exomes secreted by variant B cells were characterized by the protein content, electronic microscopy, and cell internalization assays. Critically, exosomes purified from LDL-treated variant B cell promoted cell proliferation, migration, and an increment in lactate concentration. Our results suggest that an autocrine phenomenon induced by exosomes in chemoresistant cells may induce modifications on signaling mechanisms of the p53/Mdm2 axis and activation of p70 ribosomal protein kinase S6. Moreover, the specific down-regulated profile of chaperones Hsp90 and Hsp70 secretion inside the exosomes of the chemoresistant variant could be associated with this phenomenon. Therefore, autocrine activation mediated by exosomes and the effect of LDL internalization may influence changes in exosome chaperone content and modulate proliferative signaling pathways, increasing the aggressiveness of MDA-MB-231 chemoresistant cells.

Characterization of pre-operative anemia in patients undergoing surgery by a gynecologic oncologist and association with post-operative complications.

OBJECTIVE: Anemia is prevalent in patients with gynecologic cancers and is associated with increased peri-operative morbidity. We aimed to characterize risk factors for pre-operative anemia and describe outcomes among patients undergoing surgery by a gynecologic oncologist to identify potential areas for impactful intervention. METHODS: We analyzed major surgical cases performed by a gynecologic oncologist in the National Surgical Quality Improvement Program (NSQIP) database from 2014 to 2019. Anemia was defined as hematocrit <36%. Demographic characteristics and peri-operative variables for patients with and without anemia were compared using bivariable tests. Odds of peri-operative complications in patients stratified by pre-operative anemia were calculated using logistic regression models. RESULTS: Among 60 017 patients undergoing surgery by a gynecologic oncologist, 23.1% had pre-operative anemia. Women with ovarian cancer had the highest rate of pre-operative anemia at 39.7%. Patients with advanced-stage cancer had a higher risk of anemia than early-stage disease (42.0% vs 16.3%, p≤0.001). In a logistic regression model adjusting for potential demographic, cancer-related, and surgical confounders, patients with pre-operative anemia had increased odds of infectious complications (odds ratio (OR) 1.16, 95% CI 1.07 to 1.26), thromboembolic complications (OR 1.39, 95% CI 1.15 to 1.68), and blood transfusion (OR 5.78, 95% CI 5.34 to 6.26). CONCLUSIONS: There is a high rate of anemia in patients undergoing surgery by a gynecologic oncologist, particularly those with ovarian cancer and/or advanced malignancy. Pre-operative anemia is associated with increased odds of peri-operative complications. Interventions designed to screen for and treat anemia in this population have the potential for significant impact on surgical outcomes.

"The simple life experiences that every other human gets": Desire for normalcy among adolescents and young adults with advanced cancer.

BACKGROUND: Adolescents and young adults (AYAs) with advanced cancer identify normalcy as an important component of quality end-of-life care. We sought to define domains of normalcy and identify ways in which clinicians facilitate or hinder normalcy during advanced cancer care. PROCEDURE: This was a secondary analysis of a qualitative study that aimed to identify priority domains for end-of-life care. Content analysis of semi-structured interviews among AYAs aged 12-39 years with advanced cancer, caregivers, and clinicians was used to evaluate transcripts. Coded excerpts were reviewed to identify themes related to normalcy. RESULTS: Participants included 23 AYAs with advanced cancer, 28 caregivers, and 29 clinicians. Participants identified five domains of normalcy including relationships, activities, career/school, milestones, and appearance. AYAs and caregivers identified that clinicians facilitate normalcy through exploration of these domains with AYAs, allowing flexibility in care plans, identification of short-term and long-term goals across normalcy domains, and recognizing losses of normalcy that occur during cancer care. CONCLUSIONS: AYAs with cancer experience multiple threats to normalcy during advanced cancer care. Clinicians can attend to normalcy and improve AYA quality of life by acknowledging these losses through ongoing discussions on how best to support domains of normalcy and by reinforcing AYA identities beyond a cancer diagnosis.

eIF4A/PDCD4 Pathway, a Factor for Doxorubicin Chemoresistance in a Triple-Negative Breast Cancer Cell Model.

Cells employ several adaptive mechanisms under conditions of accelerated cell division, such as the unfolded protein response (UPR). The UPR is composed of a tripartite signaling system that involves ATF6, PERK, and IRE1, which maintain protein homeostasis (proteostasis). However, deregulation of protein translation initiation could be associated with breast cancer (BC) chemoresistance. Specifically, eukaryotic initiation factor-4A (eIF4A) is involved in the unfolding of the secondary structures of several mRNAs at the 5' untranslated region (5'-UTR), as well as in the regulation of targets involved in chemoresistance. Importantly, the tumor suppressor gene PDCD4 could modulate this process. This regulation might be disrupted in chemoresistant triple negative-BC (TNBC) cells. Therefore, we characterized the effect of doxorubicin (Dox), a commonly used anthracycline medication, on human breast carcinoma MDA-MB-231 cells. Here, we generated and characterized models of Dox chemoresistance, and chemoresistant cells exhibited lower Dox internalization levels followed by alteration of the IRE1 and PERK arms of the UPR and triggering of the antioxidant Nrf2 axis. Critically, chemoresistant cells exhibited PDCD4 downregulation, which coincided with a reduction in eIF4A interaction, suggesting a sophisticated regulation of protein translation. Likewise, Dox-induced chemoresistance was associated with alterations in cellular migration and invasion, which are key cancer hallmarks, coupled with changes in focal adhesion kinase (FAK) activation and secretion of matrix metalloproteinase-9 (MMP-9). Moreover, eIF4A knockdown via siRNA and its overexpression in chemoresistant cells suggested that eIF4A regulates FAK. Pro-atherogenic low-density lipoproteins (LDL) promoted cellular invasion in parental and chemoresistant cells in an MMP-9-dependent manner. Moreover, Dox only inhibited parental cell invasion. Significantly, chemoresistance was modulated by cryptotanshinone (Cry), a natural terpene purified from the roots of Salvia brandegeei. Cry and Dox co-exposure induced chemosensitization, connected with the Cry effect on eIF4A interaction. We further demonstrated the Cry binding capability on eIF4A and in silico assays suggest Cry inhibition on the RNA-processing domain. Therefore, strategic disruption of protein translation initiation is a druggable pathway by natural compounds during chemoresistance in TNBC. However, plasmatic LDL levels should be closely monitored throughout treatment.

Translation initiation and its relationship with metabolic mechanisms in cancer development, progression and chemoresistance.

Pathways that regulate protein homeostasis (proteostasis) in cells range from mRNA processing to protein degradation; perturbations in regulatory mechanisms of these pathways can lead to oncogenic cellular processes. Protein synthesis modulation failures are common phenomena in cancer cells, wherein specific conditions that promote the translation of protein factors promoting carcinogenesis are present. These specific conditions may be favored by metabolic lipid alterations like those found in metabolic syndrome and obesity. Protein translation modifications have been described in obesity, favoring the translation of protein targets that benefit lipid accumulation; a determining factor is the activity of the cap-binding eukaryotic translation initiation factor 4E (eIF4E), a crosstalk in protein translation and lipogenesis. Besides, alterations of protein translation initiation steps are critical participants for the development of both pathogenic conditions, cancer, and obesity. This chapter is focused on the regulation of recognition and processing of carcinogenic-mRNA and the connections among lipid metabolism and cell signaling pathways that promote oncogenesis, tumoral microenvironment generation and potentially the development of chemoresistance. We performed an in-depth analysis of events, such as those occurring in obesity and dyslipidemias, that may influence protein translation, driving the recognition of certain mRNAs and favoring cancer development and chemoresistance.

Patient, Family, and Clinician Perspectives on Location of Death for Adolescents and Young Adults With Cancer.

PURPOSE: Adolescents and young adults (AYAs) with cancer have high rates of hospital deaths. It is not clear if this reflects their preferences or barriers to dying at home. METHODS: Between December 2018 and January 2021, we conducted in-depth interviews with AYAs (age 12-39 years) with stage IV or recurrent cancer, family caregivers including bereaved caregivers, and clinicians of AYAs with cancer. Patients were asked about their priorities for care including location of death, caregivers were asked what was most important in the care of their AYA family member, and clinicians were asked to reflect on priorities identified through caring for AYAs. Directed content analysis was applied to interview data, and themes regarding location of death were developed. RESULTS: Eighty individuals (23 AYAs, 28 caregivers, and 29 clinicians) participated in interviews. Most AYAs and caregivers preferred a home death. However, some AYAs and caregivers opted for a hospital death to alleviate caregiver burden or protect siblings from the perceived trauma of witnessing a home death. Lack of adequate services to manage intractable symptoms at home and insufficient caregiver support led some AYAs/caregivers to opt for hospital death despite a preference for home death. Participants acknowledged the value of hospice while also pointing out its limitations in attaining a home death. CONCLUSION: Although most AYAs prefer to die at home, this preference is not always achieved. Robust home-based services for effective symptom management and caregiver support are needed to close the gap between preferred and actual location of death for AYAs.

LDL Promotes Disorders in ß-Cell Cholesterol Metabolism, Implications on Insulin Cellular Communication Mediated by EVs.

Dyslipidemia is described as a hallmark of metabolic syndrome, promoting a stage of metabolic inflammation (metainflammation) that could lead to misbalances in energetic metabolism, contributing to insulin resistance, and modifying intracellular cholesterol pathways and the renin-angiotensin system (RAS) in pancreatic islets. Low-density lipoprotein (LDL) hypercholesterolemia could disrupt the tissue communication between Langerhans ß-cells and hepatocytes, wherein extracellular vesicles (EVs) are secreted by ß-cells, and exposition to LDL can impair these phenomena. ß-cells activate compensatory mechanisms to maintain insulin and metabolic homeostasis; therefore, the work aimed to characterize the impact of LDL on ß-cell cholesterol metabolism and the implication on insulin secretion, connected with the regulation of cellular communication mediated by EVs on hepatocytes. Our results suggest that ß-cells can endocytose LDL, promoting an increase in de novo cholesterol synthesis targets. Notably, LDL treatment increased mRNA levels and insulin secretion; this hyperinsulinism condition was associated with the transcription factor PDX-1. However, a compensatory response that maintains basal levels of intracellular calcium was described, mediated by the overexpression of calcium targets PMCA1/4, SERCA2, and NCX1, together with the upregulation of the unfolded protein response (UPR) through the activation of IRE1 and PERK arms to maintain protein homeostasis. The LDL treatment induced metainflammation by IL-6, NF-κB, and COX-2 overexpression. Furthermore, LDL endocytosis triggered an imbalance of the RAS components. LDL treatment increased the intracellular levels of cholesterol on lipid droplets; the adaptive ß-cell response was portrayed by the overexpression of cholesterol transporters ABCA1 and ABCG1. Therefore, lipotoxicity and hyperinsulinism induced by LDL were regulated by the natural compound auraptene, a geranyloxyn coumarin modulator of cholesterol-esterification by ACAT1 enzyme inhibition. EVs isolated from ß-cells impaired insulin signaling via mTOR/p70S6Kα in hepatocytes, a phenomenon regulated by auraptene. Our results show that LDL overload plays a novel role in hyperinsulinism, mechanisms associated with a dysregulation of intracellular cholesterol, lipotoxicity, and the adaptive UPR, which may be regulated by coumarin-auraptene; these conditions explain the affectations that occur during the initial stages of insulin resistance.

Patient, Family, and Clinician Perspectives on End-of-Life Care Quality Domains and Candidate Indicators for Adolescents and Young Adults With Cancer.

Importance: End-of-life care quality indicators specific to adolescents and young adults (AYAs) aged 12 to 39 years with cancer have not been developed. Objective: To identify priority domains for end-of-life care from the perspectives of AYAs, family caregivers, and clinicians, and to propose candidate quality indicators reflecting priorities. Design, Setting, and Participants: This qualitative study was conducted from December 6, 2018, to January 5, 2021, with no additional follow-up. In-depth interviews were conducted with patients, family caregivers, and clinicians and included a content analysis of resulting transcripts. A multidisciplinary advisory group translated priorities into proposed quality indicators. Interviews were conducted at the Dana-Farber Cancer Institute, Kaiser Permanente Northern California, Kaiser Permanente Southern California, and an AYA cancer support community (lacunaloft.org). Participants included 23 AYAs, 28 caregivers, and 29 clinicians. Exposure: Stage IV or recurrent cancer. Main Outcomes and Measures: Care priorities. Results: Interviews were conducted with 23 patients (mean [SD] age, 29.3 [7.3] years; 12 men [52%]; 18 White participants [78%]), 28 family caregivers (23 women [82%]; 14 White participants [50%]), and 29 clinicians (20 women [69%]; 13 White participants [45%]). Caregivers included 22 parents (79%), 5 spouses or partners (18%), and 1 other family member (4%); the 29 clinicians included 15 physicians (52%), 6 nurses or nurse practitioners (21%), and 8 social workers or psychologists (28%). Interviews identified 7 end-of-life priority domains: attention to physical symptoms, attention to quality of life, psychosocial and spiritual care, communication and decision-making, relationships with clinicians, care and treatment, and independence. Themes were consistent across the AYA age range and participant type. Although some domains were represented in quality indicators developed for adults, unique domains were identified, as well as AYA-specific manifestations of existing domains. For example, quality of life included global quality of life; attainment of life goals, legacy, and meaning; support of personal relationships; and normalcy. Within communication and decision-making, domains included communication early in the disease course, addressing prognosis and what to expect at the end of life, and opportunity for AYAs to hold desired roles in decision-making. Care and treatment domains relevant to cancer therapy, use of life-prolonging measures, and location of death emphasized the need for preference sensitivity rather than a standard path. This finding differs from existing adult indicators that propose that late-life chemotherapy, intensive measures, and hospital death should be rare. Conclusions and Relevance: The findings of this qualitative study suggest that AYAs with cancer have priorities for care at the end of life that are not fully encompassed in existing indicators for adults. Use of new indicators for this young population may better reflect patient- and family-centered experiences of quality care.

Recent Advances by In Silico and In Vitro Studies of Amyloid-ß 1-42 Fibril Depicted a S-Shape Conformation.

The amyloid-ß 1-42 (Aß1-42) peptide is produced by proteolytic cleavage of the amyloid precursor protein (APP) by sequential reactions that are catalyzed by γ and ß secretases. Aß1-42, together with the Tau protein are two principal hallmarks of Alzheimer's disease (AD) that are related to disease genesis and progression. Aß1-42 possesses a higher aggregation propensity, and it is able to form fibrils via nucleated fibril formation. To date, there are compounds available that prevent Aß1-42 aggregation, but none have been successful in clinical trials, possibly because the Aß1-42 structure and aggregation mechanisms are not thoroughly understood. New molecules have been designed, employing knowledge of the Aß1-42 structure and are based on preventing or breaking the ionic interactions that have been proposed for formation of the Aß1-42 fibril U-shaped structure. Recently, a new Aß1-42 fibril S-shaped structure was reported that, together with its aggregation and catalytic properties, could be helpful in the design of new inhibitor molecules. Therefore, in silico and in vitro methods have been employed to analyze the Aß1-42 fibril S-shaped structure and its aggregation to obtain more accurate Aß1-42 oligomerization data for the design and evaluation of new molecules that can prevent the fibrillation process.

Exploring the structure and conformational landscape of human leptin. A molecular dynamics approach.

Leptin is a hormone that regulates energy homeostasis, inflammation, hematopoiesis and immune response, among other functions (Houseknecht et al., 1998; Zhang et al., 1995; Paz-Filho et al., 2010). To obtain its crystallographic structure, it was necessary to substitute a tryptophan for a glutamic acid at position 100, thus creating a mutant leptin that has been reported to have biological activity comparable to the activity of the wild type but that crystallizes more readily. Here, we report a comparative study of the conformational space of WT and W100E leptin using molecular dynamics simulations performed at 300, 400, and 500 K. We detected differences between the interactions of the two proteins with local and distal effects, resulting in changes in the conformation, accessible surface area, compactness, electrostatic potential and dynamic behavior. Additionally, the series of unfolding events that occur when leptin is subjected to high temperature differs for the two constructs. We observed that both proteins are mostly unstructured after 20 ns of MD simulation at 500 K. However, WT leptin maintains a significant amount of secondary structure in helix α2, while the most stable region of W100E leptin is helix α3. Furthermore, we found that the region between residues 25 and 42 might adopt interconverting secondary structures ranging from α-helices and random coils to ß-strand structures. Thus, this region can be considered an intrinsically disordered region. This atomistic description supports our understanding of leptin signaling and consequently might facilitate the use of leptin in treatments for the pathophysiologies in which it is implicated.