Long interspersed nuclear elements safeguard neural progenitors from precocious differentiation

Long interspersed nuclear element-1 (L1 or LINE-1) is a highly abundant mobile genetic element in both humans and mice, comprising almost 20% of each genome. L1s are silenced by several mechanisms, as their uncontrolled expression has the potential to induce genomic instability. However, L1s are paradoxically expressed at high levels in differentiating neural progenitor cells. Using in vitro and in vivo techniques to modulate L1 expression, we report that L1s play a critical role in both human and mouse brain development by regulating the rate of neural differentiation in a reverse-transcription-independent manner.

An in vivo neuroimmune organoid model to study human microglia phenotypes

Microglia are specialized brain-resident macrophages that play crucial roles in brain development, homeostasis, and disease. However, until now, the ability to model interactions between the human brain environment and microglia has been severely limited. To overcome these limitations, we developed an in vivo xenotransplantation approach that allows us to study functionally mature human microglia (hMGs) that operate within a physiologically relevant, vascularized immunocompetent human brain organoid (iHBO) model. Our data show that organoid-resident hMGs gain human-specific transcriptomic signatures that closely resemble their in vivo counterparts. In vivo two-photon imaging reveals that hMGs actively engage in surveilling the human brain environment, react to local injuries, and respond to systemic inflammatory cues. Finally, we demonstrate that the transplanted iHBOs developed here offer the unprecedented opportunity to study functional human microglia phenotypes in health and disease and provide experimental evidence for a brain-environment-induced immune response in a patient-specific model of autism with macrocephaly.

Predictive factors for recurrence and outcomes in T1a renal cell carcinoma: Analysis of the INMARC (International Marker Consortium for Renal Cancer) database

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Background: Stage migration in renal cell carcinoma (RCC) has led to an increasing proportion of diagnoses at earlier clinical tumor stage and has rendered the phenomenon of the ‘small renal mass’ as a dominant presenting clinical paradigm. While thought of as being low risk, emerging knowledge about heterogeneity of RCC histologies and consequent impact on prognosis, in addition to awareness of impact of functional decline and demographic drivers on outcomes led us to further explore outcomes and predictive factors in T1a RCC patients treated with surgical resection. Methods: The INMARC database was queried for patients with small renal masses (≤ 4 cm) who underwent surgery via partial or radical nephrectomy and who presented without nodal or distant metastases. Patients were stratified into two groups based on having recurrence (distant or loco-regional) or not. Primary outcome was overall survival (OS). Multivariable analyses (MVA) were performed to analyze clinicopathological variables associated with recurrence and identify predictors of recurrence, cancer-specific mortality (CSM), and all-cause mortality (ACM). Kaplan-Meier analyses (KMA) were performed to compare recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS) between histology types clear cell, chromophobe, papillary, and “other.” Results: We analyzed 1,878 cT1aN0M0 RCC patients; 101 (5.4%) developed recurrence (median follow up 53.6 months; median time to recurrence 19.3 months); 51.1% developed distant recurrence, 35.6% had loco-regional recurrence, and 13.9% experienced distant and loco-regional recurrence. MVA demonstrated age (HR=1.02, p=0.02), sex (HR=1.71, p=0.045), diabetes (HR=1.94, p=0.006), high/unclassified grade (HR=2.82-4.40, p<0.001-0.007), papillary (HR=0.37, p=0.013) and other (HR=2.51, p=0.019) RCC as predictive factors for recurrence. MVA identified high/unclassified grade (HR=3.17-6.22, p=0.002-0.003) and papillary RCC (HR=0.12, p=0.036) as predictive factors for CSM. MVA for ACM demonstrated age (HR=1.03, p<0.001), non-Caucasian race (HR=0.85, p<0.001), high grade (HR=1.42, p=0.024), recurrence (HR=1.86, p=0.003), and GFR<45 (HR=2.89, p<0.001) to be independent risk factors. KMA comparing Clear Cell, Papillary, Chromophobe and Other RCC revealed significant differences for 5-year CSS (97.8% vs. 99.3% vs. 98.5% vs. 87.0%, p=0.018) and 5-year RFS (92.4% vs. 96.0% vs. 97.8% vs. 81.7%, p<0.001), but not 5-year OS (89.4% vs. 85.2% vs. 93.2% vs. 73.7%, p=0.34). Conclusions: We noted differential outcomes in T1a RCC based on histology and grade for recurrence and CSM, while renal functional decline in addition to pathological factors and recurrence were predictive for ACM. These findings suggest consideration to refine management and post treatment surveillance strategies in T1a RCC.

A comparison of radiographic and morphometric characteristics and outcomes in T3a pathologically upstaged and non-upstaged renal cell carcinoma

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Background: A significant portion of patients presenting with clinically localized stage 1-2 renal cell carcinoma are pathologically upstaged to Stage 3 following surgical intervention. This is due to previously undetected extension into the renal venous system, perirenal or renal sinus fat, or collecting system. Improved detection of potential T3 upstaging may prompt changes in disease management, which may impact patient survival. We sought to compare pathologically upstaged and non-upstaged T3a RCC cases to identify characteristics of upstaged masses, predictors of T3a disease, and impact on oncological outcomes. Methods: We conducted a single center retrospective analysis of patients with pathologic T3a RCC who underwent surgical intervention. The cohort was divided into a group of patients with masses not preoperatively identified as cT3a (upstaged, cT1-cT2/pT3a) and a group of patients with masses preoperatively identified as cT3a (non-upstaged, cT3a/pT3a) for descriptive and outcomes analyses. We sought to delineate proportion of under-diagnosed pT3a RCC, location of upstaged disease, and predictors of upstaging. Primary outcome was overall survival (OS) and secondary outcome was recurrence-free survival (RFS). Multivariate analyses (MVA) were performed to identify predictors of T3a invasion site and outcomes. Kaplan Meier survival analyses (KMA) were performed to compare survival outcomes. Results: We analyzed 185 patients, of which 120 (64.9%) were upstaged and 65 (35.1%) were non-upstaged. When compared to non-upstaged masses, upstaged masses were significant for smaller size (6.8 vs 8.2 cm, p=0.008), lower RENAL score (8.7 vs 9.9, p<0.001), less hilar involvement (29.2% vs 86.2%, p<0.001), and increased exophyticity (41.7% vs 23.1%, p=0.011). On pathology, upstaged masses had greater proportions of perirenal fat invasion (53.3% vs 33.8%, p=0.011), but less venous system (44.2% vs 78.5%, p<0.001) and sinus fat invasion (35.8% vs 63.1%, p<0.001) compared to non-upstaged masses. RENAL domains R (OR=2.30-2.49, p=0.037-0.042), E (OR=0.39-2.32, p=0.003-0.009), and L (OR=0.53-7.70, p=0.001-0.031) were independent predictors for T3a disease foci. MVA demonstrated an association between non-upstaged status and recurrence (HR=2.01, p=0.043) but not overall mortality (HR=1.27, p=0.581). KMA noted better RFS in upstaged patients compared to non-upstaged patients (80.8% vs 75.4%, p=0.002), but no OS differences between upstaged and non-upstaged patients (74.2% vs 83.1%, p=0.209). Conclusions: Pathologically upstaged T3a RCC is associated with distinct morphology and invasion patterns and higher recurrence-free survival outcomes compared to non-upstaged T3a RCC. RENAL domains can assist in identifying masses with upstaging potential, predicting their invasion site, and performing preoperative risk stratification.

Characteristics and outcomes of T1a renal cell carcinoma presenting with metastasis

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Background: T1a renal cell carcinoma (RCC) is associated with excellent cure rates. However, a small fraction present with metastasis. We sought to determine the clinical characteristics, variables associated with synchronous metastasis, and survival outcomes in patients with pT1a and cT1a RCC using the National Cancer Database (NCDB). We secondarily evaluated whether surgery impacted risk of all cause mortality in cT1a RCC with synchronous lung and bone metastasis. Methods: From 2004 to 2019, all cases of RCC in patients age ≥18 were extracted from NCDB. pT1a and cT1a RCC were characterized as those 1) with no metastasis at diagnosis, 2) with synchronous metastasis [pT1aNxM1 at diagnosis]. Impact of surgery on all cause mortality was not evaluated for cT1a with synchronous metastasis to liver and brain due to low sample sizes. Results: The table describes selected characteristics of the cohorts. On multivariable logistic regression, diagnosis of pT1a with synchronous metastasis was associated with age (OR 1.02), male sex (OR 1.64), tumor size (OR 1.84), cN1 (OR 1.08), sarcomatoid (OR 5.50), tumor grade (OR 2.84) (p<0.005 for these variables); and inversely with diagnosis in 2016-2019 (OR 0.66, p=0.044) and papillary histology (OR 0.45, p<0.001). On multivariable Cox regression of the cT1a cohort, ACM was associated with Charlson score (HR 1.50, p<0.001), metastasis to >1 site (HR 2.48, p=0.032), and inversely with radical (HR 0.42, p<0.001) and partial nephrectomy (HR 0.31, p<0.001). In cT1a with lung metastasis, partial (HR 0.06, p=0.049) and radical nephrectomy (HR 0.17, p=0.006) was inversely associated with ACM, while surgery of distant site was not. In cT1a with bone metastasis, partial (HR 0.21, p<0.001) and radical nephrectomy (HR 0.32, p<0.001) were the only variables inversely associated with ACM. 5-year overall survival for pT1a with synchronous metastasis is 39.4%; for cT1a with synchronous metastasis is 20.9%. Conclusions: Known prognostic features were associated with synchronous metastasis in T1a RCC. Surgical resection of primary site may impact risk of all cause mortality in select cases of synchronous metastatic disease. [Table: see text]

Proposal for reclassification of upstaged T1 and T2 and pathological T3 RCC based on improved alignment of survival analyses

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Background: Patients with pathologically upstaged tumors have worse survival outcomes than their non-upstaged matched counterparts. However, we do know that original clinical tumor staging does still predict outcomes. We sought to examine if pathologic upstaging incrementally may more rationally stratify cancer specific survival outcomes. Methods: Multi-institutional (Emory, TMDU, UCSD) retrospective analysis of patients with renal cell carcinoma who underwent partial or radical nephrectomy between 1998-2020. Patients were divided into cT1 upstaged to pT3 (cT1/pT3), cT2 non-upstaged (cT2/pT2), cT2 upstaged to pT3 (cT2/pT3), and cT3 non-upstaged (cT3/pT3). Patients were analyzed for demographics, clinical parameters, and post-surgical outcomes. Primary outcome was cancer specific mortality (CSM). Secondary outcomes were all cause mortality and recurrence free survival. Cox regression was utilized to analyze factors associated with outcomes. Kaplan Meier analysis (KMA) was performed to analyze 5-year cancer specific survival. ROC analysis was utilized to compare predictive value of AJCC 8th edition TNM staging vs proposed staging. Results: 1093 patients were analyzed (283 cT1/pT3, 237 cT2/pT2, 244 cT2/pT3, and 329 cT3/pT3). Median follow-up was 25.9 months. Cox regression demonstrated that cT2/pT3 (HR 2.7, p<0.001 vs. cT1/pT3 [referent]) and cT3/pT3 (HR 2.6, p<0.001 vs. cT1/pT3 [referent]) were significantly associated with worsened cancer specific mortality, while cT1/pT3 (HR 0.4, p<0.001 vs. cT3/pT3 [referent]) and cT2/pT2 (HR 0.4, p<0.001 vs. cT3/pT3 [referent]) were associated with improved cancer specific mortality. Based on this, we proposed to realign cT1/pT3 with cT2/pT2 and cT2/pT3 with cT3/pT3. KMA revealed significant differences in 5-year cancer specific survival (cT1/pT3 82%, cT2/pT2 81%, cT2/pT3 67%, and cT3/pT3 60%, p<0.001). There were significant differences in 5-year overall survival (cT1/pT3 63%, cT2/pT2 67%, cT2/pT3 49%, and cT3/pT3 49%, p<0.001), and 5-year recurrence free survival (cT1/pT3 80%, cT2/pT2 83%, cT2/pT3 70%, and cT3/pT3 59%, p<0.001) on KMA. ROC analysis revealed an AUC of 0.529 for CSM and AUC of 0.502 for ACM using the current AJCC 8th edition TNM staging. ROC analysis revealed an AUC of 0.597 for CSM and AUC of 0.545 for our new proposal. Conclusions: Our analysis suggests that cT1 tumors pathologically upstaged to pT3 behave more similarly to pT2 tumors. Further delineation of pathologically upstaged tumors may more rationally stratify cancer specific survival outcomes to guide patient counseling and clinical decision making.

Radical nephrectomy in medically underserved patients: Selection bias and disparity in surgical health care delivery

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Background: Disparities in outcomes of renal cell carcinoma (RCC) exist with respect to survival outcomes between different ethnic, and socioeconomic groups. We sought to evaluate disparities in delivery of surgical care between medically underserved (MU) and non-medically underserved (NMU) patients. Methods: We conducted a single-center retrospective analysis of consecutive patients presenting with localized renal cortical neoplasms who underwent surgical excision [Radical (RN) or Partial Nephrectomy (PN)] at an academic tertiary-care referral center. The cohort was divided into MU and NMU groups and descriptive analyses were conducted for demographics and clinical disease characteristics, type of surgery, time to surgery, estimated blood loss, and 30-day total and major complications (Clavien-Dindo, ≥3). Cochran-Armitage trend analysis was conducted to evaluate for surgical trends, and logistic regression multivariable analyses (MVA) were conducted for type of surgery and major complications. Results: 1418 patients were analyzed (MU n=334/NMU n=1084). Comparing MU vs. NMU, no differences were noted for age (p=0.612), Charlson Comorbidity Index (p=0.803), tumor size (p=0.236), or time to surgery (p=0.482). Significantly greater proportions of white patients were noted in NMU (60.6% vs. MU=45.5%, p<0.001) and higher proportion of RN in MU (47% vs. NMU=40.4%, p=0.028). Subgroup analyses of PN groups revealed no differences with respect to demographics, tumor size (p=0.33), major complications (p=0.66), or blood loss (p=0.583). Subgroup analysis of RN revealed significantly higher proportion of non-white patients (p=0.019) and patients with diabetes (p=0.019). MVA for predictors for receipt of RN were non-white (OR1.4, p=0.002), MU (OR=1.32, p=0.043), age (OR=1.01, p=0.009) and treatment year (OR=0.913, p<0.001). MVA for predictors for 30 day major complications demonstrated RN (OR=0.913 p<0.001). Cochran-Armitage trend analysis indicated that both MU and NMU had significant increases in PN between 2003 and 2021 (p<0.0001). Conclusions: Despite overall similarities with respect to demographics and clinical disease characteristics and time to surgery, MU status was associated with a significantly higher odds of receiving a RN at a tertiary care referral center, which represents a disparity in care and possible selection bias. Nonetheless, RN was also associated with a decreased risk of complications. While trends have demonstrated an increase in proportion of PN for both NMU and MU groups, comparative underutilization of PN in MU patients may be associated with increased downstream risks to health. Further investigation is requisite.

Consideration for reclassification of pathologically upstaged T3a renal cell carcinomas

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Background: Pathological upstaging to pT3a disease can occur after the surgical treatment of clinical T1 and T2 Renal Cell Carcinomas (RCCs), and this upstaging has been previously shown to be associated with poorer outcomes. With an intent to delve deeper into the disparateness in outcomes of pT3a disease, we investigated the survival of patients with an initial clinical stage of cT1, cT2 and cT3a. Methods: Using the National Cancer Database (NCDB), patients with RCC were categorized by pathological and clinical staging of RCC according to the American Joint Committee on Cancer Guidelines (AJCC). The primary outcome was measured as overall survival (OS) at the end of follow up. Five-year survival rates and Kaplan-Meier Analysis assessed the differences between cT1 → pT3a, cT2 → pT2, cT2 → pT3a, and cT3a → pT3a. Multivariable cox regression (MVA) assessed predictors OS with age, sex, ethnicity, Charlson Score, socioeconomic status, geography, tumor size histology and grade, lymph node metastasis, surgical margins, and surgery type (partial versus radical nephrectomy) as covariates. Results: 53908 patients were analyzed (10789 cT1 → pT3a, 22183 cT2 → pT2, 9676 cT2 → pT3a, 11260 cT3a → pT3a, mean follow up 62.3 months). Of all pT3a patients, 64.5% were upstaged from cT1-2. MVA for OS demonstrated Hispanic ethnicity to be protective (hazard ratio [HR]=0.88, P<0.001) and revealed different histologic risks. MVA for OS demonstrated that cT2 → pT3a (HR=1.33, P<0.001, cT1 → pT3a [ref]) and cT3a → pT3a (HR=1.35, P<0.001, cT1 → pT3a [ref]) were associated with worsened OS, and that cT1 → pT3a and cT2 → pT2 (HR=0.96, P<0.052, cT1 → pT3a [ref]) were associated with improved OS. Kaplan-Meier analysis revealed a difference in 5 year overall survival as well (cT1→pT3a 72%, cT2→pT2 77%, cT2→pT3a 61%, and cT3a→pT3a 59%, p < 0.001). Conclusions: Patients with cT1 upstaged to pT3a have similar outcomes to cT2 staged to pT2 and better outcomes than cT2 upstaged with the latter’s outcomes being more like cT3a staged to pT3a. The TNM staging system from AJCC for RCCs should consider these outcomes and adjust the grouping for RCCs accordingly.

Trends and outcomes in localized renal cell carcinoma with sarcomatoid dedifferentiation: Analysis of the National Cancer Database

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Background: Sarcomatoid dedifferentiation in Renal Cell Carcinoma (sRCC) is well known to be a subtype with poor prognosis with a high rate of synchronous metastases at presentation. Nonetheless, outcomes in a contemporary cohort of patients with localized sRCC are not well characterized in a population-based study. We sought to determine the clinical characteristics, temporal trends in prevalence, and survival outcomes in patients with localized sarcomatoid RCC. Methods: From 2004-2019, all 440,230 cases of RCC in patients ≥18 years were extracted from the National Cancer Database; of these, 3.3% (14,713) had sarcomatoid dedifferentiation. Trend analyses were conducted using Cochran-Armitage test of trend. Multivariable Cox Proportional-Hazards regression was used to determine the impact of clinical and pathologic characteristics on all cause mortality (ACM) in patients with non-metastatic sRCC. Actuarial Overall Survival (OS) was computed with Kaplan-Meier analysis (KMA), with sub-analysis performed for patients with AJCC Prognostic Stages I-III (Stage). Clear cell was reference histology for all analyses. Holm adjustment for multiple comparisons was applied when necessary. Results: Sarcomatoid dedifferentiation increased from 1.9% in 2004 to 4.1% in 2019, average annual percentage change (AAPC) 0.060 (p<0.001). sRCC with synchronous metastasis decreased from 48.7% in 2004 to 38.7% in 2019, AAPC -0.028 (p<0.001). Of all sRCC, 39.3% had synchronous metastasis to lung, 17.9% to bone, 5.3% to liver, 2.2% to brain, 35.3% to >1 site. On Cox regression for non-metastatic sRCC, ACM was associated with age (HR 1.02, p<0.001), Charlson comorbidity (HR 1.21, p<0.001), tumor size (HR 1.04, p<0.001), cN1 (HR 1.01, p<0.001), collecting duct (HR 2.33, p=0.002), medullary (HR 4.75, p=0.031), and RCC unspecified (HR 1.46, p<0.001) histology, tumor grade (HR 1.30, p<0.001); and inversely with partial (HR 0.19, p<0.001) and radical (HR 0.32, p<0.001) nephrectomy. In non-metastatic sRCC, 5-year OS was 52.9%. Substratification showed 5-year OS of 72.9% for Stage I, 60.4% Stage II, and 40.9% for Stage III sRCC (p<0.001). Conclusions: The findings constitute the largest retrospective characterization of localized RCC with sarcomatoid dedifferentiation; sRCC has increased in prevalence, while patients presenting with synchronous metastases have decreased. Despite the latter trend, outcomes in patients with localized sRCC are poor and associated with patient comorbidity, stage, and associated histological findings. While partial and radical nephrectomy was associated with improved outcomes, these findings must be interpreted with caution and are likely secondary to significant selection bias. Future studies investigating the underlying biology driving increased sarcomatoid dedifferentiation despite generalized downward stage migration in RCC are requisite.

Impact of number of positive lymph nodes on prognostic stratification in renal cell carcinoma: Analysis of the National Cancer Database

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Background: Lymph node positivity in Renal Cell Carcinoma (RCC) is associated with worsened oncologic outcomes. However, the actual prognostic significance of node positivity is poorly understood. Currently, American Joint Committee on Cancer (AJCC) Stage III RCC includes both node-positive pN1 and node-negative pN0 disease. We hypothesize that (1) there is a threshold in number of pathologic node positivity that distinguishes favorable risk from poor risk nodal disease, and (2) current categorization of pN1 can be subdivided into pN1 and pN2 based this threshold. We tested our hypothesis using the National Cancer Database (NCDB). Methods: From 2004-2019, all cases of RCC were queried in patients age ≥18. Patients with pathologic node positive disease and without synchronous metastasis were selected for analysis to minimize confounding from metastatic burden. Multivariable Cox Proportional-Hazards regression tested association between number of pathologically positive lymph nodes and all-cause mortality (ACM), adjusting for clinical and pathologic co-variables. Receiver Operator Characteristic (ROC) Curve analyses employing the concordance probability method evaluated performance of potential cut-points for pN2 node-positivity. Kaplan-Meier analyses (KMA) compared these thresholds against overall survival (OS) in non-metastatic Stage IV RCC. Results: 28,590 patients with above criteria were identified, of which 13.6% had pN1. On multivariable analyses, increased pathologic node positivity was associated with increased hazard of ACM (HR 1.19, 95% Confidence Interval [CI] 1.17-1.20, p<0.001). ROC mapping of all possible lymph node thresholds from ≥2 to ≥10, with stage IV as the highest point, showed comparable concordance probability among these cutoffs 0.26-0.33, AUC=0.656. On KMA, when threshold was set at ≥3, 5-year OS was no longer significantly different from non-metastatic Stage IV RCC as illustrated by overlapping confidence intervals. We designated pN1 as 1-2 pathologic positive nodes, and pN2 as ≥3 pathologic positive nodes. 5-year OS for Stage III pN0 was 69.4% (95% CI 68.4-70.5), for Stage III pN1 was 41.4% (95% CI 39.0-43.8), for Stage III pN2 was 31.8% (95% CI 28.2-35.9%), and for non-metastatic Stage IV was (30.0%, 95% CI 28.2-32.0%). On multivariable analyses, pN2 exhibited 38% greater hazard of ACM (HR 3.31, 95% CI 2.24-2.54, p<0.001) compared to pN1 (HR 2.39, 95% CI 2.24-2.54, p<0.001). Conclusions: These findings represent one of the largest characterizations of impact of positive nodal counts on prognostic stratification in RCC. Pathologic node positivity could be stratified to pN1 and pN2, with pN2 conferring poor prognostic risk comparable to non-metastatic Stage IV pN0 disease. Although further validation studies are warranted, consideration should be given towards stratifying Stage III pN2 patients to a higher risk group.

Diagnosis of systemic lupus erythematosus with early manifestation of an eosinophilic pleural effusion

A woman in her 70s with a history of Crohn’s disease presented to the emergency department with dyspnoea, cough and intermittent fevers. Evaluation revealed a pleural effusion with neutrophil predominance, and initial suspicion of infection prompted a short course of antibiotic therapy. However, the patient subsequently developed recurrent pleural effusion with eosinophilic predominance. Serological data confirmed a diagnosis of systemic lupus erythematosus (SLE) and the patient was started on appropriate treatment.

This case presents an initial manifestation of eosinophilic-dominant pleural effusion in SLE. Current guidelines in treating pleural effusions do not explore rheumatological causes. However, we believe that our case demonstrates the value of a prompt investigation for rheumatological aetiologies in an otherwise unclassified eosinophilic-predominant pleural effusion. Such an investigation should include serological data as an important confirmatory marker for the diagnosis of SLE.

Lamin B1 decline underlies age-related loss of adult hippocampal neurogenesis

Neurogenesis in the adult hippocampus declines with age, a process that has been implicated in cognitive and emotional impairments. However, the mechanisms underlying this decline have remained elusive. Here, we show that the age-dependent downregulation of lamin B1, one of the nuclear lamins in adult neural stem/progenitor cells (ANSPCs), underlies age-related alterations in adult hippocampal neurogenesis. Our results indicate that higher levels of lamin B1 in ANSPCs safeguard against premature differentiation and regulate the maintenance of ANSPCs. However, the level of lamin B1 in ANSPCs declines during aging. Precocious loss of lamin B1 in ANSPCs transiently promotes neurogenesis but eventually depletes it. Furthermore, the reduction of lamin B1 in ANSPCs recapitulates age-related anxiety-like behavior in mice. Our results indicate that the decline in lamin B1 underlies stem cell aging and impacts the homeostasis of adult neurogenesis and mood regulation.