Circulating biomarkers of kidney angiomyolipoma and cysts in tuberous sclerosis complex patients.

Patients with tuberous sclerosis complex (TSC) develop multi-organ disease manifestations, with kidney angiomyolipomas (AML) and cysts being one of the most common and deadly. Early and regular AML/cyst detection and monitoring are vital to lower TSC patient morbidity and mortality. However, the current standard of care involves imaging-based methods that are not designed for rapid screening, posing challenges for early detection. To identify potential diagnostic screening biomarkers of AML/cysts, we performed global untargeted metabolomics in blood samples from 283 kidney AML/cyst-positive or -negative TSC patients using mass spectrometry. We identified 7 highly sensitive chemical features, including octanoic acid, that predict kidney AML/cysts in TSC patients. Patients with elevated octanoic acid have lower levels of very long-chain fatty acids (VLCFAs), suggesting that dysregulated peroxisome activity leads to overproduction of octanoic acid via VLCFA oxidation. These data highlight AML/cysts blood biomarkers for TSC patients and offers valuable metabolic insights into the disease.

Patient organization perspective: a research roadmap for Okur-Chung Neurodevelopmental Syndrome.

Okur-Chung neurodevelopmental syndrome (OCNDS) is an ultra-rare disorder caused by variants in the CSNK2A1 gene. CSNK2A1 encodes for the alpha subunit of casein kinase 2 (CK2), a serine/threonine kinase critical in neural development. CK2 is implicated in many human pathologies, including viral infections, cancer, inflammation, cardiovascular, neurodegenerative, and psychiatric diseases. However, the mechanism of action for the CSNK2A1 variants observed in OCNDS is not fully understood, although studies suggest a loss of function or altered substrate specificity. There are no approved treatments for OCNDS, and current treatments focus on symptom management. The CSNK2A1 Foundation was established in 2018 and aims to find a cure for OCNDS and provide support to affected individuals. OCNDS presents with symptoms at varying severity, including developmental delay/intellectual disabilities, autism, disrupted sleep, speech delays/inability to speak, short stature, and, in ~25% of cases, epilepsy. The foundation has developed a research toolbox that is readily available to researchers worldwide and has awarded ~$1 million in grant funding. These efforts have provided valuable insights into CK2 biology and the natural history of OCNDS. However, additional efforts are needed to fully characterize the disease mechanism and investigate potential treatment interventions. Continued investigation into CK2 and its role in neural development holds promise for a better understanding of OCNDS and related disorders in the future. To accelerate research, we have developed a research roadmap highlighting key focus areas of landscape analysis/toolbox expansion, biomarker development, and therapeutic testing through a series of steps that are nonlinear; we expect these efforts to guide decision-making for therapeutic exploration whether that be drug repurposing, gene therapy, novel drug discovery, or a combination. In this perspective article, we describe OCNDS and the CSNK2A1 gene, highlight gaps in OCNDS research, discuss the research roadmap, and offer the founder's perspective on our growth and future opportunities.

Patient organization perspective: a research roadmap for Okur-Chung Neurodevelopmental Syndrome Okur-Chung Neurodevelopmental Syndrome (OCNDS) is an ultra-rare disorder caused by variants in the CSNK2A1 gene.CSNK2A1 creates a subunit of CK2, a critical protein in brain development among other biological processes.There are no approved treatments for OCNDS, and current suggested treatments focus on symptom management.Individuals with OCNDS exhibit many symptoms at varying severity levels, including developmental delay/intellectual disabilities, autism, disrupted sleep, speech delays/inability to speak, short stature, and in approximately 25% of cases, epilepsy. We think that seizure prevalence may be underreported due to lack of extended EEG recordings for OCNDS patients and that seizures may preferentially occur at night as has been observed in other autism spectrum disorders.The CSNK2A1 Foundation was established in 2018 and aims to find a cure for OCNDS and provide support to affected individuals. The CSNK2A1 Foundation's research tools and efforts have provided valuable insights into the biology of OCNDS and the natural history of the disorder. However, additional efforts are needed to fully understand how OCNDS affects the body and investigate potential treatment approaches.To accelerate OCNDS research, the foundation has developed a research roadmap that is presented in this perspective article. We describe OCNDS and the CSNK2A1 gene, highlight gaps in OCNDS research, discuss the research roadmap, and offer the founder's perspective on our growth and future opportunities.

Racial differences in the dermatological manifestations of tuberous sclerosis complex and the potential effects on diagnosis and care.

Background: Tuberous sclerosis complex (TSC) is an autosomal dominant neurocutaneous disorder of non-malignant tumor growths throughout major organ systems and neurological, neuropsychiatric, renal, and pulmonary co-morbidities. Skin manifestations are readily visible, often develop early in life, and are major features that contribute to TSC diagnosis. Medical photographs of such manifestations are commonly shown as examples from White individuals creating a potential barrier to accurately identifying these features in darker skinned individuals. Objectives: The aim of this report is to raise awareness of dermatological manifestations associated with TSC, compare their appearance by race, and consider how recognition of these features could impact diagnosis and treatment of TSC. Design and Methods: We conducted a retrospective chart review at the TSC Center of Excellence (TSCOE) at the Kennedy Krieger Institute, which included all patients in the center from 2009 (inception) through the end of the calendar year 2015 and analyzed data from the TSC Alliance Natural History Database (NHD). Results: Among TSCOE patients, 50% of Black patients were diagnosed before the age of 1 year, compared with 70% of White patients. NHD data corroborated this trend showing a significant difference with only 38% of Blacks as compared with 50% of Whites were diagnosed at age ⩽1 year. A significant difference was observed where White participants had higher odds of having received genetic testing in both data sets. While no differences in the total number of TSC features was observed in either data set, shagreen patches and cephalic fibrous plaques were more frequently recorded in the NHD for Black individuals. Conclusion: We highlight a disparity in the representation of Black participants within the NHD, TSCOE, and TSC trials, in addition to differences in utilization of molecular testing and topical mechanistic target of rapamycin (mTOR) inhibitor therapy between Black and White individuals. We show a trend toward later diagnosis age in Black individuals. These differences between races warrant further study across additional clinical sites and other minority groups.

Differences in skin manifestations between races in individuals with tuberous sclerosis complex and the potential effects of these differences on diagnosis and care Background: To our knowledge, tuberous sclerosis complex (TSC) does not affect races at different frequencies; however, observations in clinical settings anecdotally, and results from research studies, suggest a disparity in the representation and diagnosis of Black individuals with TSC. Historically, it has been noted that TSC facial features, such as angiofibromas, present differently in individuals with darker skin tones and are often misdiagnosed leading to delays in TSC diagnosis and treatment. Objectives: The aim of this publication is to identify differences in TSC skin features between Black and White individuals to raise awareness in the clinics and community. In addition, we provide insight into how these differences can affect the timing of TSC diagnosis and subsequent treatment regimens. We aim to highlight these potential disparities to ensure improved timing in diagnosis and treatment regimens for all affected by TSC in the future. Design and Methods: Differences between Black and White individuals with TSC were observed looking at historical medical data collected at a TSC Center of Excellence (TSCOE) on all patients seen in the center from 2009 through the end of 2015 and in the TSC Alliance Natural History Database (NHD) that has been collecting clinical data on individuals with TSC since 2006. Results: We observed that Black individuals are less likely to be diagnosed at ⩽1 year of age as compared with White individuals within the NHD. Data from the TSCOE support these findings but were not statistically significant. We observed a difference in NHD participation with only 150 Black individuals participating, representing 6% of total NHD participants. Our data indicate a difference between Black and White individuals both in the TSCOE and NHD showing that Black individuals are less likely to receive genetic testing, utilize topical mTOR therapy, and participate in TSC clinical trials. Conclusion: Given the observed trends, outreach and education to clinicians and other healthcare providers is needed to inform of these differences. Given that skin manifestations play an essential role in early recognition of TSC and timely referral to TSC specialists, we hope these data lead to improvement in the recognition of TSC in darker skinned individuals at earlier ages, thus improving clinical outcomes associated with TSC manifestations by optimizing treatment early in life.

Unexpected effects of ivermectin and selamectin on inducible CreER activity in mice.

BACKGROUND: Anti-parasitics are frequently used in research animal facilities to treat a multitude of common infections, with pinworms and fur mites being amongst the most common. Ivermectin and selamectin are common oral and topical treatments for these infections, respectively. Although commonly thought to be innocuous to both the research animals and any transgenic elements that the animals may carry, evidence exists that ivermectin is capable of activating the recombinase activity of at least one CreER. The goal of the current study was to determine if there was an effect of either anti-parasitic agent on the activity of CreER proteins in transgenic mice. CASE PRESENTATION: We analyzed the offspring of transgenic mice exposed to either ivermectin or selamectin during pregnancy and nursing. Through analysis of reporter genes co-expressed with multiple, independently generated transgenic CreER drivers, we report here that ivermectin and selamectin both alter recombinase activity and thus may have unintended consequences on gene inactivation studies in mice. CONCLUSIONS: Although the mechanisms by which ivermectin and selamectin affect CreER activity in the offspring of treated dams remain unclear, the implications are important nonetheless. Treatment of pregnant transgenic mice with these anti-parasitics has the potential to alter transgene activity in the offspring. Special considerations should be made when planning treatment of transgenic mice with either of these pharmacologics.

DEPDC5 haploinsufficiency drives increased mTORC1 signaling and abnormal morphology in human iPSC-derived cortical neurons.

Mutations in the DEPDC5 gene can cause epilepsy, including forms with and without brain malformations. The goal of this study was to investigate the contribution of DEPDC5 gene dosage to the underlying neuropathology of DEPDC5-related epilepsies. We generated induced pluripotent stem cells (iPSCs) from epilepsy patients harboring heterozygous loss of function mutations in DEPDC5. Patient iPSCs displayed increases in both phosphorylation of ribosomal protein S6 and proliferation rate, consistent with elevated mTORC1 activation. In line with these findings, we observed increased soma size in patient iPSC-derived cortical neurons that was rescued with rapamycin treatment. These data indicate that human cells heterozygous for DEPDC5 loss-of-function mutations are haploinsufficient for control of mTORC1 signaling. Our findings suggest that human pathology differs from mouse models of DEPDC5-related epilepsies, which do not show consistent phenotypic differences in heterozygous neurons, and support the need for human-based models to affirm and augment the findings from animal models of DEPDC5-related epilepsy.

Heterogeneity of Neural Stem Cells in the Ventricular-Subventricular Zone.

In this chapter, heterogeneity is explored in the context of the ventricular-subventricular zone, the largest stem cell niche in the mammalian brain. This niche generates up to 10,000 new neurons daily in adult mice and extends over a large spatial area with dorso-ventral and medio-lateral subdivisions. The stem cells of the ventricular-subventricular zone can be subdivided by their anatomical position and transcriptional profile, and the stem cell lineage can also be further subdivided into stages of pre- and post-natal quiescence and activation. Beyond the stem cells proper, additional differences exist in their interactions with other cellular constituents of the niche, including neurons, vasculature, and cerebrospinal fluid. These variations in stem cell potential and local interactions are discussed, as well as unanswered questions within this system.

Location-dependent maintenance of intrinsic susceptibility to mTORC1-driven tumorigenesis.

Neural stem/progenitor cells (NSPCs) of the ventricular-subventricular zone (V-SVZ) are candidate cells of origin for many brain tumors. However, whether NSPCs in different locations within the V-SVZ differ in susceptibility to tumorigenic mutations is unknown. Here, single-cell measurements of signal transduction intermediates in the mechanistic target of rapamycin complex 1 (mTORC1) pathway reveal that ventral NSPCs have higher levels of signaling than dorsal NSPCs. These features are linked with differences in mTORC1-driven disease severity: introduction of a pathognomonic Tsc2 mutation only results in formation of tumor-like masses from the ventral V-SVZ. We propose a direct link between location-dependent intrinsic growth properties imbued by mTORC1 and predisposition to tumor development.

Neural stem cell heterogeneity through time and space in the ventricular-subventricular zone.

BACKGROUND: The origin and classification of neural stem cells (NSCs) has been a subject of intense investigation for the past two decades. Efforts to categorize NSCs based on their location, function and expression have established that these cells are a heterogeneous pool in both the embryonic and adult brain. The discovery and additional characterization of adult NSCs has introduced the possibility of using these cells as a source for neuronal and glial replacement following injury or disease. To understand how one could manipulate NSC developmental programs for therapeutic use, additional work is needed to elucidate how NSCs are programmed and how signals during development are interpreted to determine cell fate. OBJECTIVE: This review describes the identification, classification and characterization of NSCs within the large neurogenic niche of the ventricular-subventricular zone (V-SVZ). METHODS: A literature search was conducted using Pubmed including the keywords "ventricular-subventricular zone," "neural stem cell," "heterogeneity," "identity" and/or "single cell" to find relevant manuscripts to include within the review. A special focus was placed on more recent findings using single-cell level analyses on neural stem cells within their niche(s). RESULTS: This review discusses over 20 research articles detailing findings on V-SVZ NSC heterogeneity, over 25 articles describing fate determinants of NSCs, and focuses on 8 recent publications using distinct single-cell analyses of neural stem cells including flow cytometry and RNA-seq. Additionally, over 60 manuscripts highlighting the markers expressed on cells within the NSC lineage are included in a chart divided by cell type. CONCLUSIONS: Investigation of NSC heterogeneity and fate decisions is ongoing. Thus far, much research has been conducted in mice however, findings in human and other mammalian species are also discussed here. Implications of NSC heterogeneity established in the embryo for the properties of NSCs in the adult brain are explored, including how these cells may be redirected after injury or genetic manipulation.

PhDAHP1 is required for floral volatile benzenoid/phenylpropanoid biosynthesis in Petunia × hybrida cv 'Mitchell Diploid'.

Floral volatile benzenoid/phenylpropanoid (FVBP) biosynthesis consists of numerous enzymatic and regulatory processes. The initial enzymatic step bridging primary metabolism to secondary metabolism is the condensation of phosphoenolpyruvate (PEP) and erythrose-4-phosphate (E4P) carried out via 3-DEOXY-D-ARABINO-HEPTULOSONATE-7-PHOSPHATE (DAHP) synthase. Here, identified, cloned, localized, and functionally characterized were two DAHP synthases from the model plant species Petunia × hybrida cv 'Mitchell Diploid' (MD). Full-length transcript sequences for PhDAHP1 and PhDAHP2 were identified and cloned using cDNA SMART libraries constructed from pooled MD corolla and leaf total RNA. Predicted amino acid sequence of PhDAHP1 and PhDAHP2 proteins were 76% and 80% identical to AtDAHP1 and AtDAHP2 from Arabidopsis, respectively. PhDAHP1 transcript accumulated to relatively highest levels in petal limb and tube tissues, while PhDAHP2 accumulated to highest levels in leaf and stem tissues. Through floral development, PhDAHP1 transcript accumulated to highest levels during open flower stages, and PhDAHP2 transcript remained constitutive throughout. Radiolabeled PhDAHP1 and PhDAHP2 proteins localized to plastids, however, PhDAHP2 localization appeared less efficient. PhDAHP1 RNAi knockdown petunia lines were reduced in total FVBP emission compared to MD, while PhDAHP2 RNAi lines emitted 'wildtype' FVBP levels. These results demonstrate that PhDAHP1 is the principal DAHP synthase protein responsible for the coupling of metabolites from primary metabolism to secondary metabolism, and the ultimate biosynthesis of FVBPs in the MD flower.