Caregivers of People With Mild Cognitive Impairment and Dementia: Characterizing Social and Psychological Outcomes.

OBJECTIVE: Little is known about caregiving across the spectrum of cognitive impairment [mild cognitive impairment (MCI) to dementia] and how early life and sociocultural factors affect caregiver health. In this study, we characterized differences between caregivers of those with MCI versus those with dementia. METHODS: A total of 158 caregivers were enrolled in this cross-sectional study, most of whom were dementia caregivers (65%). Caregivers completed questionnaires on depressive symptoms, self-rated health (SRH), perceived burden and stress, as well as psychosocial and demographic measures. RESULTS: Caregivers of those with MCI reported fewer depressive symptoms and lower stress and burden compared with dementia caregivers. In adjusted analyses caregivers with greater stress reported more depressive symptoms. For SRH, at lower stress levels, having a sibling die before age 18 (ie, early life adversity) was associated with poorer SRH; at higher stress levels, having early life adversity was associated with better SRH. At lower burden levels, more live births were associated with worse SRH; at higher burden levels, more live births were associated with better SRH. CONCLUSIONS: Early life factors are relevant for caregivers of those with cognitive impairment and targeted prevention and early intervention may be helpful in alleviating caregiver burden and stress.

Clinical validation of a ctDNA-Based Assay for Multi-Cancer Detection: An Interim Report from a Vietnamese Longitudinal Prospective Cohort Study of 2795 Participants.

The SPOT-MAS assay "Screening for the Presence Of Tumor by Methylation And Size" detects the five most common cancers in Vietnam by evaluating circulating tumor DNA in the blood. Here, we validated its performance in a prospective multi-center clinical trial, K-DETEK. Our analysis of 2795 participants from 14 sites across Vietnam demonstrates its ability to detect cancers in asymptomatic individuals with a positive predictive value of 60%, with 83.3% accuracy in detecting tumor location. We present a case report to support further using SPOT-MAS as a complementary method to achieve early cancer detection and provide the opportunity for early treatment.

Fragment length profiles of cancer mutations enhance detection of circulating tumor DNA in patients with early-stage hepatocellular carcinoma.

BACKGROUND: Late detection of hepatocellular carcinoma (HCC) results in an overall 5-year survival rate of less than 16%. Liquid biopsy (LB) assays based on detecting circulating tumor DNA (ctDNA) might provide an opportunity to detect HCC early noninvasively. Increasing evidence indicates that ctDNA detection using mutation-based assays is significantly challenged by the abundance of white blood cell-derived mutations, non-tumor tissue-derived somatic mutations in plasma, and the mutational tumor heterogeneity. METHODS: Here, we employed concurrent analysis of cancer-related mutations, and their fragment length profiles to differentiate mutations from different sources. To distinguish persons with HCC (PwHCC) from healthy participants, we built a classification model using three fragmentomic features of ctDNA through deep sequencing of thirteen genes associated with HCC. RESULTS: Our model achieved an area under the curve (AUC) of 0.88, a sensitivity of 89%, and a specificity of 82% in the discovery cohort consisting of 55 PwHCC and 55 healthy participants. In an independent validation cohort of 54 PwHCC and 53 healthy participants, the established model achieved comparable classification performance with an AUC of 0.86 and yielded a sensitivity and specificity of 81%. CONCLUSIONS: Our study provides a rationale for subsequent clinical evaluation of our assay performance in a large-scale prospective study.

Ultra-Deep Sequencing of Plasma-Circulating DNA for the Detection of Tumor- Derived Mutations in Patients with Nonmetastatic Colorectal Cancer.

Identification of tumor-derived mutation (TDM) in liquid biopsies (LB), especially in early-stage patients, faces several challenges, including low variant-allele frequencies, interference by white blood cell (WBC)-derived mutations (WDM), benign somatic mutations and tumor heterogeneity. Here, we addressed the above-mentioned challenges in a cohort of 50 nonmetastatic colorectal cancer patients, via a workflow involving parallel sequencing of paired WBC- and tumor-gDNA. After excluding potential false positive mutations, we detected at least one TDM in LB of 56% (28/50) of patients, with the majority showing low-patient coverage, except for one TDM mapped to KMT2D that recurred in 30% (15/30) of patients.

Genetic landscape of recessive diseases in the Vietnamese population from large-scale clinical exome sequencing.

Accurate profiling of population-specific recessive diseases is essential for the design of cost-effective carrier screening programs. However, minority populations and ethnic groups, including Vietnamese, are still underrepresented in existing genetic studies. Here, we reported the first comprehensive study of recessive diseases in the Vietnamese population. Clinical exome sequencing data of 4503 disease-associated genes obtained from a cohort of 985 Vietnamese individuals was analyzed to identify pathogenic variants, associated diseases and their carrier frequencies in the population. A total of 118 recessive diseases associated with 164 pathogenic or likely pathogenic variants were identified, among which 28 diseases had carrier frequencies of at least 1% (1 in 100 individuals). Three diseases were prevalent in the Vietnamese population with carrier frequencies of 2-12 times higher than in the world populations, including beta-thalassemia (1 in 23), citrin deficiency (1 in 31), and phenylketonuria (1 in 40). Seven novel pathogenic and two likely pathogenic variants associated with nine recessive diseases were discovered. The comprehensive profile of recessive diseases identified in this study enables the design of cost-effective carrier screening programs specific to the Vietnamese population.

Fenfluramine for seizures associated with Sunflower syndrome.

AIM: To determine the efficacy of fenfluramine on seizure frequency in patients with Sunflower syndrome. Secondary endpoints were changes in electroencephalogram (EEG) characteristics, cognitive functioning, executive functioning, and quality of life. METHOD: In this open-label study, patients underwent a 4-week baseline period, followed by 3 months of treatment. An oral solution of fenfluramine was administered twice daily for 3 months. The dose was titrated up to a maximum dose of 0.7mg/kg/day or 26mg/day. Cardiac safety was monitored by transthoracic echocardiogram and electrocardiogram. EEGs, abbreviated neuropsychological testing, and questionnaires were administered before starting the study medication and again at the end of the treatment period. RESULTS: Ten patients (eight females, two males; mean age 13y 4mo [SD 4y 11mo], range 7-24y) were enrolled in the study. Nine of the 10 patients completed the core study, eight of whom met the primary endpoint. There were no observations of cardiac valvulopathy or pulmonary hypertension during the study. INTERPRETATION: Treatment with low-dose fenfluramine resulted in a clinically significant reduction in seizure frequency, including hand-waving episodes. Fenfluramine may be an effective treatment option for patients with Sunflower syndrome. What this paper adds Nine patients with Sunflower syndrome were treated with fenfluramine. Eight patients were responders, displaying a ≥30% reduction in seizure activity. Six patients experienced a ≥70% reduction in hand-waving episodes. Improvements on electroencephalogram were observed after treatment with fenfluramine. None of the patients developed evidence of cardiac valvulopathy or pulmonary hypertension.

Evaluation of a Liquid Biopsy Protocol using Ultra-Deep Massive Parallel Sequencing for Detecting and Quantifying Circulation Tumor DNA in Colorectal Cancer Patients.

The identification and quantification of actionable mutations are critical for guiding targeted therapy and monitoring drug response in colorectal cancer. Liquid biopsy (LB) based on plasma cell-free DNA analysis has emerged as a noninvasive approach with many clinical advantages over conventional tissue sampling. Here, we developed a LB protocol using ultra-deep massive parallel sequencing and validated its clinical performance for detection and quantification of actionable mutations in three major driver genes (KRAS, NRAS and BRAF). The assay showed a 92% concordance for mutation detection between plasma and paired tissues and great reliability in quantification of variant allele frequency.

Molecular Insights into the Mechanisms of SUN1 Oligomerization in the Nuclear Envelope.

The LINC complex is found in a wide variety of organisms and is formed by the transluminal interaction between outer- and inner-nuclear-membrane KASH and SUN proteins, respectively. Most extensively studied are SUN1 and SUN2 proteins, which are widely expressed in mammals. Although SUN1 and SUN2 play functionally redundant roles in several cellular processes, more recent studies have revealed diverse and distinct functions for SUN1. While several recent in vitro structural studies have revealed the molecular details of various fragments of SUN2, no such structural information is available for SUN1. Herein, we conduct a systematic analysis of the molecular relationships between SUN1 and SUN2, highlighting key similarities and differences that could lead to clues into their distinct functions. We use a wide range of computational tools, including multiple sequence alignments, homology modeling, molecular docking, and molecular dynamic simulations, to predict structural differences between SUN1 and SUN2, with the goal of understanding the molecular mechanisms underlying SUN1 oligomerization in the nuclear envelope. Our simulations suggest that the structural model of SUN1 is stable in a trimeric state and that SUN1 trimers can associate through their SUN domains to form lateral complexes. We also ask whether SUN1 could adopt an inactive monomeric conformation as seen in SUN2. Our results imply that the KASH binding domain of SUN1 is also inhibited in monomeric SUN1 but through weaker interactions than in monomeric SUN2.

Analytical validation and clinical utilization of K-4CARE™: a comprehensive genomic profiling assay with personalized MRD detection.

Background: Biomarker testing has gradually become standard of care in precision oncology to help physicians select optimal treatment for patients. Compared to single-gene or small gene panel testing, comprehensive genomic profiling (CGP) has emerged as a more time- and tissue-efficient method. This study demonstrated in-depth analytical validation of K-4CARE, a CGP assay that integrates circulating tumor DNA (ctDNA) tracking for residual cancer surveillance. Methods: The assay utilized a panel of 473 cancer-relevant genes with a total length of 1.7 Mb. Reference standards were used to evaluate limit of detection (LOD), concordance, sensitivity, specificity and precision of the assay to detect single nucleotide variants (SNVs), small insertion/deletions (Indels), gene amplification and fusion, microsatellite instability (MSI) and tumor mutational burden (TMB). The assay was then benchmarked against orthogonal methods using 155 clinical samples from 10 cancer types. In selected cancers, top tumor-derived somatic mutations, as ranked by our proprietary algorithm, were used to detect ctDNA in the plasma. Results: For detection of somatic SNVs and Indels, gene fusion and amplification, the assay had sensitivity of >99%, 94% and >99% respectively, and specificity of >99%. Detection of germline variants also achieved sensitivity and specificity of >99%. For TMB measurement, the correlation coefficient between whole-exome sequencing and our targeted panel was 97%. MSI analysis when benchmarked against polymerase chain reaction method showed sensitivity of 94% and specificity of >99%. The concordance between our assay and the TruSight Oncology 500 assay for detection of somatic variants, TMB and MSI measurement was 100%, 89%, and 98% respectively. When CGP-informed mutations were used to personalize ctDNA tracking, the detection rate of ctDNA in liquid biopsy was 79%, and clinical utility in cancer surveillance was demonstrated in 2 case studies. Conclusion: K-4CARE™ assay provides comprehensive and reliable genomic information that fulfills all guideline-based biomarker testing for both targeted therapy and immunotherapy. Integration of ctDNA tracking helps clinicians to further monitor treatment response and ultimately provide well-rounded care to cancer patients.

High Seroprevalence of Anti-SARS-CoV-2 Antibodies in Children in Vietnam: An Observational, Hospital-Based Study.

Background: The robustness of sero-surveillance has delineated the high burden of SARS-CoV-2 infection in children; however, these existing data showed wide variation. This study aimed to identify the serostatus of antibodies against SARS-CoV-2 and associated factors among children following the fourth pandemic wave in Vietnam. Methods: A cross-sectional study was conducted at Vietnam National Children's Hospital (VNCH) between March 13 and April 3, 2022. Thus, 4032 eligible children seeking medical care for any medical condition not related to acute COVID-19 infection were tested for IgG SARS-CoV-2 antibodies by ADVIA Centaur® SARS-CoV-2 IgG (sCOVG) assay using the residuals of routine blood samples. Results: The median age of enrolled children was 39 (IQR = 14−82) months. The overall seropositive prevalence was 59.2% (95%CI = 57.6−60.7) and the median antibody titer was 4.78 (IQR 2.38−9.57) UI/mL. The risk of seropositivity and the median antibody titer were not related to gender (58.6% versus 60.1%, 4.9 versus 4.6 UI/mL, all p > 0.05). Children aged ≤12 months were likely to be seropositive compared to children aged 36 to <60 months (59.2% versus 57.5%, p = 0.49) and those aged ≥144 months (59.2% versus 65.5%, p = 0.16). Children aged ≥144 months exhibited a significantly higher titer of protective COVID-19 antibodies than other age groups (p < 0.001). In multivariate logistic regression, we observed independent factors associated with SARS-CoV-2 seropositivity, including the age 13 to <36 months (OR = 1.29, 95%CI = 1.06−1.56, p = 0.01), 60 to <144 months (OR = 0.79, 95%CI = 0.67−0.95, p = 0.01), ≥144 months (OR = 1.84, 95%CI = 1.21−2.8, p = 0.005), the presence of infected household members (OR = 2.36, 95%CI = 2.06−2.70, p < 0.001), participants from Hanoi (OR = 1.54, 95%CI = 1.34−1.77, p < 0.001), underlying conditions (OR = 0.71, 95%CI = 0.60−0.85, p ≤ 0.001), and using corticosteroids or immunosuppressants (OR = 0.64, 95%CI = 0.48−0.86, p = 0.003). Conclusions: This study highlights a high seroprevalence of antibodies against SARS-CoV-2 among children seeking medical care for non-acute COVID-19-related conditions in a tertiary children's hospital in Hanoi, Vietnam. In the context of reopening in-person schools and future emerging COVID-19 variants, this point will also be a key message about the necessity of "rush-out" immunization coverage for children, especially those under the age of five years.

Baseline Assessment of Children's Meals and Healthy Beverage Options Prior to a State-Level Healthy Default Beverage (HDB) Law.

In January 2020, Hawai'i became the second state with a healthy default beverage (HDB) law, requiring restaurants to offer HDBs with their children's meals. This observational study presents baseline characteristics of restaurants with a children's menu and meal. The study describes pre-law beverage options to inform future HDB policy language, implementation, and evaluation. Between November and December 2019, data were collected from a statewide sample of unique restaurants (N = 383) with health inspection permits. Restaurants were assessed separately for a children's menu and meal using website reviews, telephone calls, and in-person visits. Meals were evaluated for pre-law beverage type and compliance. Logistic regression was used to estimate the likelihood of having a children's menu and meal. Most of the restaurants were full-service (70.2%) and non-chains (67.9%). While 49.3% of restaurants had a children's menu, only 16.7% had a children's meal. Significant predictors of having a children's menu were being full-service, national/international or local chains, neighbor island (non-Honolulu) locations, and hotel locations. Only being a national/international chain significantly predicted having a children's meal. Although 35.9% of children's meals offered a non-sugar-sweetened beverage (SSB) option, only 3.1% offered law-compliant beverages. Inclusion of an SSB default option (60.9%) and not specifying the type of default beverage were the predominant factors for pre-law non-compliance. Results support the need for HDB regulations, especially for national/international chains, which were most likely to have children's meals, and provide data to inform policies in other jurisdictions.

Pathogenic Variant Profile of Hereditary Cancer Syndromes in a Vietnamese Cohort.

BACKGROUND: Hereditary cancer syndromes (HCS) are responsible for 5-10% of cancer cases. Genetic testing to identify pathogenic variants associated with cancer predisposition has not been routinely available in Vietnam. Consequently, the prevalence and genetic landscape of HCS remain unknown. METHODS: 1165 Vietnamese individuals enrolled in genetic testing at our laboratory in 2020. We performed analysis of germline mutations in 17 high- and moderate- penetrance genes associated with HCS by next generation sequencing. RESULTS: A total of 41 pathogenic variants in 11 genes were detected in 3.2% individuals. The carrier frequency was 4.2% in people with family or personal history of cancer and 2.6% in those without history. The percentage of mutation carriers for hereditary colorectal cancer syndromes was 1.3% and for hereditary breast and ovarian cancer syndrome was 1.6%. BRCA1 and BRCA2 mutations were the most prevalent with the positive rate of 1.3% in the general cohort and 5.1% in breast or ovarian cancer patients. Most of BRCA1 mutations located at the BRCA C-terminus domains and the top recurrent mutation was NM_007294.3:c.5251C>T (p.Arg1751Ter). One novel variant NM_000038.6(APC):c.6665C>A (p.Pro2222His) was found in a breast cancer patient with a strong family history of cancer. A case study of hereditary cancer syndrome was illustrated to highlight the importance of genetic testing. CONCLUSION: This is the first largest analysis of carrier frequency and mutation spectrum of HCS in Vietnam. The findings demonstrate the clinical significance of multigene panel testing to identify carriers and their at-risk relatives for better cancer surveillance and management strategies.

Liquid biopsy uncovers distinct patterns of DNA methylation and copy number changes in NSCLC patients with different EGFR-TKI resistant mutations.

Targeted therapy with tyrosine kinase inhibitors (TKI) provides survival benefits to a majority of patients with non-small cell lung cancer (NSCLC). However, resistance to TKI almost always develops after treatment. Although genetic and epigenetic alterations have each been shown to drive resistance to TKI in cell line models, clinical evidence for their contribution in the acquisition of resistance remains limited. Here, we employed liquid biopsy for simultaneous analysis of genetic and epigenetic changes in 122 Vietnamese NSCLC patients undergoing TKI therapy and displaying acquired resistance. We detected multiple profiles of resistance mutations in 51 patients (41.8%). Of those, genetic alterations in EGFR, particularly EGFR amplification (n = 6), showed pronounced genome instability and genome-wide hypomethylation. Interestingly, the level of hypomethylation was associated with the duration of response to TKI treatment. We also detected hypermethylation in regulatory regions of Homeobox genes which are known to be involved in tumor differentiation. In contrast, such changes were not observed in cases with MET (n = 4) and HER2 (n = 4) amplification. Thus, our study showed that liquid biopsy could provide important insights into the heterogeneity of TKI resistance mechanisms in NSCLC patients, providing essential information for prediction of resistance and selection of subsequent treatment.

Positive association between neighborhood retail alcohol outlet access and hospital admissions for alcohol withdrawal syndrome in New Orleans.

Objectives: We used treatment for alcohol withdrawal syndrome as an objective surrogate marker to investigate the relationship between alcohol-related health outcomes and home neighborhood alcohol outlet density and alcohol advertising density.Methods: Mixed effects logistic regression examined whether alcohol outlet density or alcohol advertisement density within either one-quarter mile or one-half mile of individuals' home address was associated with treatment for alcohol withdrawal.Results: Adjusted models showed outlet and advertising density, particularly off-sale outlet density within one-quarter mile of the home, increased the risk of hospital admission for alcohol withdrawal syndrome (AOR = 1.15).Conclusion/impact: These data inform public policy initiatives to reduce the harmful effects of alcohol by regulating the neighborhood alcohol environment.

Insights in Public Health: Development, Implementation, and Evaluation of the Prevent Diabetes, Hawai'i Campaign.

The Prevent Diabetes, Hawai'i campaign aimed to increase awareness of prediabetes by encouraging adults to take a Diabetes Risk Test and share the results with their doctors or healthcare providers. The campaign was developed based on social marketing principles, and focus groups were used to inform the marketing mix. Television, radio, digital, and print advertisements featured local actor and comedian Frank De Lima, and a website with an online Diabetes Risk Test and resources for patients and providers were promoted in all advertisements. From March 2017 to November 2019, more than 55,000 Hawai'i residents visited the campaign website. Campaign outcomes were assessed through state-added questions to the 2017 Behavioral Risk Factor Surveillance System. Overall, 35.0% of adults said that they remembered seeing or hearing an advertisement featuring Frank De Lima and/or the Prevent Diabetes, Hawai'i message. Five percent of respondents reported taking an online or paper version of the Diabetes Risk Test in the past 12 months, and an additional 19.7% said that they planned to take it. Among those who reported taking the Diabetes Risk Test, 60.2% said they had already spoken to their doctor or other healthcare provider about the test results or risk for type 2 diabetes. The State Department of Health will continue efforts to increase awareness of type 2 diabetes and prediabetes, reach priority populations most at risk, and expand availability of evidence-based lifestyle change programs.

Genetic profiling of Vietnamese population from large-scale genomic analysis of non-invasive prenatal testing data.

The under-representation of several ethnic groups in existing genetic databases and studies have undermined our understanding of the genetic variations and associated traits or diseases in many populations. Cost and technology limitations remain the challenges in performing large-scale genome sequencing projects in many developing countries, including Vietnam. As one of the most rapidly adopted genetic tests, non-invasive prenatal testing (NIPT) data offers an alternative untapped resource for genetic studies. Here we performed a large-scale genomic analysis of 2683 pregnant Vietnamese women using their NIPT data and identified a comprehensive set of 8,054,515 single-nucleotide polymorphisms, among which 8.2% were new to the Vietnamese population. Our study also revealed 24,487 disease-associated genetic variants and their allele frequency distribution, especially 5 pathogenic variants for prevalent genetic disorders in Vietnam. We also observed major discrepancies in the allele frequency distribution of disease-associated genetic variants between the Vietnamese and other populations, thus highlighting a need for genome-wide association studies dedicated to the Vietnamese population. The resulted database of Vietnamese genetic variants, their allele frequency distribution, and their associated diseases presents a valuable resource for future genetic studies.

Actionable Mutation Profiles of Non-Small Cell Lung Cancer patients from Vietnamese population.

Comprehensive profiling of actionable mutations in non-small cell lung cancer (NSCLC) is vital to guide targeted therapy, thereby improving the survival rate of patients. Despite the high incidence and mortality rate of NSCLC in Vietnam, the actionable mutation profiles of Vietnamese patients have not been thoroughly examined. Here, we employed massively parallel sequencing to identify alterations in major driver genes (EGFR, KRAS, NRAS, BRAF, ALK and ROS1) in 350 Vietnamese NSCLC patients. We showed that the Vietnamese NSCLC patients exhibited mutations most frequently in EGFR (35.4%) and KRAS (22.6%), followed by ALK (6.6%), ROS1 (3.1%), BRAF (2.3%) and NRAS (0.6%). Interestingly, the cohort of Vietnamese patients with advanced adenocarcinoma had higher prevalence of EGFR mutations than the Caucasian MSK-IMPACT cohort. Compared to the East Asian cohort, it had lower EGFR but higher KRAS mutation prevalence. We found that KRAS mutations were more commonly detected in male patients while EGFR mutations was more frequently found in female. Moreover, younger patients (<61 years) had higher genetic rearrangements in ALK or ROS1. In conclusions, our study revealed mutation profiles of 6 driver genes in the largest cohort of NSCLC patients in Vietnam to date, highlighting significant differences in mutation prevalence to other cohorts.

Ultra-Deep Massive Parallel Sequencing of Plasma Cell-Free DNA Enables Large-Scale Profiling of Driver Mutations in Vietnamese Patients With Advanced Non-Small Cell Lung Cancer.

Population-specific profiling of mutations in cancer genes is of critical importance for the understanding of cancer biology in general as well as the establishment of optimal diagnostics and treatment guidelines for that particular population. Although genetic analysis of tumor tissue is often used to detect mutations in cancer genes, the invasiveness and limited accessibility hinders its application in large-scale population studies. Here, we used ultra-deep massive parallel sequencing of plasma cell free DNA (cfDNA) to identify the mutation profiles of 265 Vietnamese patients with advanced non-small cell lung cancer (NSCLC). Compared to a cohort of advanced NSCLC patients characterized by sequencing of tissue samples, cfDNA genomic testing, despite lower mutation detection rates, was able to detect major mutations in tested driver genes that reflected similar mutation composition and distribution pattern, as well as major associations between mutation prevalence and clinical features. In conclusion, ultra-deep sequencing of plasma cfDNA represents an alternative approach for population-wide genetic profiling of cancer genes where recruitment of patients is limited to the accessibility of tumor tissue site.

CCR5 Signaling Promotes Murine and Human Hematopoietic Regeneration following Ionizing Radiation.

Hematopoietic stem and progenitor cells (HSPCs) depend on regulatory cytokines from the marrow microenvironment. From an unbiased cytokine screen of murine marrow supernatants, we identified C-C motif chemokine ligand 5 (CCL5) as an endothelial cell-secreted hematopoietic growth factor. Following treatment with CCL5, hematopoietic regeneration is accelerated and survival is prolonged after radiation. In mice with deletion of Ccr5, hematopoietic regeneration is delayed compared to control mice. Deletion of Ccr5 specifically in hematopoietic cells was sufficient to delay regeneration, while the deletion of Ccr5 in stromal/endothelial cells was not. Mechanistically, CCL5 promotes hematopoietic cell cycling and cell survival. Like murine hematopoietic cells, human hematopoietic cells (cord blood, healthy marrow, and peripheral blood) increase CCR5 expression after radiation exposure to promote cell survival. These data establish that CCL5 and CCR5 signaling play critical roles in hematopoietic regeneration and could serve as therapeutic targets to shorten the duration of myelosuppression.

Role of KASH domain lengths in the regulation of LINC complexes.

The linker of the nucleoskeleton and cytoskeleton (LINC) complex is formed by the conserved interactions between Sad-1 and UNC-84 (SUN) and Klarsicht, ANC-1, SYNE homology (KASH) domain proteins, providing a physical coupling between the nucleoskeleton and cytoskeleton that mediates the transfer of physical forces across the nuclear envelope. The LINC complex can perform distinct cellular functions by pairing various KASH domain proteins with the same SUN domain protein. For example, in Caenorhabditis elegans, SUN protein UNC-84 binds to two KASH proteins UNC-83 and ANC-1 to mediate nuclear migration and anchorage, respectively. In addition to distinct cytoplasmic domains, the luminal KASH domain also varies among KASH domain proteins of distinct functions. In this study, we combined in vivo C. elegans genetics and in silico molecular dynamics simulations to understand the relation between the length and amino acid composition of the luminal KASH domain, and the function of the SUN-KASH complex. We show that longer KASH domains can withstand and transfer higher forces and interact with the membrane through a conserved membrane proximal EEDY domain that is unique to longer KASH domains. In agreement with our models, our in vivo results show that swapping the KASH domains of ANC-1 and UNC-83, or shortening the KASH domain of ANC-1, both result in a nuclear anchorage defect in C. elegans.