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Endocrine Reviews Mar 2021Multiple endocrine neoplasia type 1 (MEN1), a rare tumor syndrome that is inherited in an autosomal dominant pattern, is continuing to raise great interest for... (Review)
Review
Multiple endocrine neoplasia type 1 (MEN1), a rare tumor syndrome that is inherited in an autosomal dominant pattern, is continuing to raise great interest for endocrinology, gastroenterology, surgery, radiology, genetics, and molecular biology specialists. There have been 2 major clinical practice guidance papers published in the past 2 decades, with the most recent published 8 years ago. Since then, several new insights on the basic biology and clinical features of MEN1 have appeared in the literature, and those data are discussed in this review. The genetic and molecular interactions of the MEN1-encoded protein menin with transcription factors and chromatin-modifying proteins in cell signaling pathways mediated by transforming growth factor β/bone morphogenetic protein, a few nuclear receptors, Wnt/β-catenin, and Hedgehog, and preclinical studies in mouse models have facilitated the understanding of the pathogenesis of MEN1-associated tumors and potential pharmacological interventions. The advancements in genetic diagnosis have offered a chance to recognize MEN1-related conditions in germline MEN1 mutation-negative patients. There is rapidly accumulating knowledge about clinical presentation in children, adolescents, and pregnancy that is translatable into the management of these very fragile patients. The discoveries about the genetic and molecular signatures of sporadic neuroendocrine tumors support the development of clinical trials with novel targeted therapies, along with advancements in diagnostic tools and surgical approaches. Finally, quality of life studies in patients affected by MEN1 and related conditions represent an effort necessary to develop a pharmacoeconomic interpretation of the problem. Because advances are being made both broadly and in focused areas, this timely review presents and discusses those studies collectively.
Topics: Adolescent; Animals; Germ-Line Mutation; Humans; Mice; Multiple Endocrine Neoplasia Type 1; Neuroendocrine Tumors; Quality of Life; Signal Transduction
PubMed: 33249439
DOI: 10.1210/endrev/bnaa031 -
Molecular Psychiatry Dec 2019Depression is a complex disorder that takes an enormous toll on individual health. As affected individuals display a wide variation in their clinical symptoms, the... (Review)
Review
Depression is a complex disorder that takes an enormous toll on individual health. As affected individuals display a wide variation in their clinical symptoms, the precise neural mechanisms underlying the development of depression remain elusive. Although it is impossible to phenocopy every symptom of human depression in rodents, the preclinical field has had great success in modeling some of the core affective and neurovegetative depressive symptoms, including social withdrawal, anhedonia, and weight loss. Adaptations in select cell populations may underlie these individual depressive symptoms and new tools have expanded our ability to monitor and manipulate specific cell types. This review outlines some of the most recent preclinical discoveries on the molecular and neurophysiological mechanisms in reward circuitry that underlie the expression of behavioral constructs relevant to depressive symptoms.
Topics: Anhedonia; Animals; Depression; Depressive Disorder, Major; Disease Models, Animal; Humans; Motivation; Reward; Social Behavior; Weight Loss
PubMed: 30967681
DOI: 10.1038/s41380-019-0415-3 -
Journal of Internal Medicine Jun 2020Mitochondrial disease presenting in childhood is characterized by clinical, biochemical and genetic complexity. Some children are affected by canonical syndromes, but... (Review)
Review
Mitochondrial disease presenting in childhood is characterized by clinical, biochemical and genetic complexity. Some children are affected by canonical syndromes, but the majority have nonclassical multisystemic disease presentations involving virtually any organ in the body. Each child has a unique constellation of clinical features and disease trajectory, leading to enormous challenges in diagnosis and management of these heterogeneous disorders. This review discusses the classical mitochondrial syndromes presenting most frequently in childhood and then presents an organ-based perspective including systems less frequently linked to mitochondrial disease, such as skin and hair abnormalities and immune dysfunction. An approach to diagnosis is then presented, encompassing clinical evaluation and biochemical, neuroimaging and genetic investigations, and emphasizing the problem of phenocopies. The impact of next-generation sequencing is discussed, together with the importance of functional validation of novel genetic variants never previously linked to mitochondrial disease. The review concludes with a brief discussion of currently available and emerging therapies. The field of mitochondrial medicine has made enormous strides in the last 30 years, with approaching 400 different genes across two genomes now linked to primary mitochondrial disease. However, many important questions remain unanswered, including the reasons for tissue specificity and variability of clinical presentation of individuals sharing identical gene defects, and a lack of disease-modifying therapies and biomarkers to monitor disease progression and/or response to treatment.
Topics: Child; Humans; Mitochondria; Mitochondrial Diseases; Mutation; Phenotype
PubMed: 32176382
DOI: 10.1111/joim.13054 -
Progress in Retinal and Eye Research Nov 2020The ABCA4 protein (then called a "rim protein") was first identified in 1978 in the rims and incisures of rod photoreceptors. The corresponding gene, ABCA4, was cloned... (Review)
Review
The ABCA4 protein (then called a "rim protein") was first identified in 1978 in the rims and incisures of rod photoreceptors. The corresponding gene, ABCA4, was cloned in 1997, and variants were identified as the cause of autosomal recessive Stargardt disease (STGD1). Over the next two decades, variation in ABCA4 has been attributed to phenotypes other than the classically defined STGD1 or fundus flavimaculatus, ranging from early onset and fast progressing cone-rod dystrophy and retinitis pigmentosa-like phenotypes to very late onset cases of mostly mild disease sometimes resembling, and confused with, age-related macular degeneration. Similarly, analysis of the ABCA4 locus uncovered a trove of genetic information, including >1200 disease-causing mutations of varying severity, and of all types - missense, nonsense, small deletions/insertions, and splicing affecting variants, of which many are located deep-intronic. Altogether, this has greatly expanded our understanding of complexity not only of the diseases caused by ABCA4 mutations, but of all Mendelian diseases in general. This review provides an in depth assessment of the cumulative knowledge of ABCA4-associated retinopathy - clinical manifestations, genetic complexity, pathophysiology as well as current and proposed therapeutic approaches.
Topics: ATP-Binding Cassette Transporters; DNA; Genetic Therapy; Humans; Mutation; Phenotype; Retinal Diseases
PubMed: 32278709
DOI: 10.1016/j.preteyeres.2020.100861 -
Biochimica Et Biophysica Acta.... Apr 2022ARPKD is a genetically inherited kidney disease that manifests by bilateral enlargement of cystic kidneys and liver fibrosis. It shows a range of severity, with 30% of... (Review)
Review
ARPKD is a genetically inherited kidney disease that manifests by bilateral enlargement of cystic kidneys and liver fibrosis. It shows a range of severity, with 30% of individuals dying early on and the majority having good prognosis if they survive the first year of life. The reasons for this variability remain unclear. Two genes have been shown to cause ARPKD when mutated, PKHD1, mutations in which lead to most of ARPKD cases and DZIP1L, which is associated with moderate ARPKD. This mini review will explore the genetics of ARPKD and discuss potential genetic modifiers and phenocopies that could affect diagnosis.
Topics: Adaptor Proteins, Signal Transducing; Animals; Humans; Polycystic Kidney, Autosomal Recessive; Polymorphism, Genetic; Prognosis; Receptors, Cell Surface; Signal Transduction; Transcription Factors
PubMed: 35032595
DOI: 10.1016/j.bbadis.2022.166348 -
Nature Cell Biology Aug 2023Lipid mobilization through fatty acid β-oxidation is a central process essential for energy production during nutrient shortage. In yeast, this catabolic process starts...
Lipid mobilization through fatty acid β-oxidation is a central process essential for energy production during nutrient shortage. In yeast, this catabolic process starts in the peroxisome from where β-oxidation products enter mitochondria and fuel the tricarboxylic acid cycle. Little is known about the physical and metabolic cooperation between these organelles. Here we found that expression of fatty acid transporters and of the rate-limiting enzyme involved in β-oxidation is decreased in cells expressing a hyperactive mutant of the small GTPase Arf1, leading to an accumulation of fatty acids in lipid droplets. Consequently, mitochondria became fragmented and ATP synthesis decreased. Genetic and pharmacological depletion of fatty acids phenocopied the arf1 mutant mitochondrial phenotype. Although β-oxidation occurs in both mitochondria and peroxisomes in mammals, Arf1's role in fatty acid metabolism is conserved. Together, our results indicate that Arf1 integrates metabolism into energy production by regulating fatty acid storage and utilization, and presumably organelle contact sites.
Topics: Animals; Mitochondria; Peroxisomes; Fatty Acids; Oxidation-Reduction; Lipid Metabolism; Homeostasis; Mammals
PubMed: 37400497
DOI: 10.1038/s41556-023-01180-2 -
Cell Feb 2024Human brain development involves an orchestrated, massive neural progenitor expansion while a multi-cellular tissue architecture is established. Continuously expanding...
Human brain development involves an orchestrated, massive neural progenitor expansion while a multi-cellular tissue architecture is established. Continuously expanding organoids can be grown directly from multiple somatic tissues, yet to date, brain organoids can solely be established from pluripotent stem cells. Here, we show that healthy human fetal brain in vitro self-organizes into organoids (FeBOs), phenocopying aspects of in vivo cellular heterogeneity and complex organization. FeBOs can be expanded over long time periods. FeBO growth requires maintenance of tissue integrity, which ensures production of a tissue-like extracellular matrix (ECM) niche, ultimately endowing FeBO expansion. FeBO lines derived from different areas of the central nervous system (CNS), including dorsal and ventral forebrain, preserve their regional identity and allow to probe aspects of positional identity. Using CRISPR-Cas9, we showcase the generation of syngeneic mutant FeBO lines for the study of brain cancer. Taken together, FeBOs constitute a complementary CNS organoid platform.
Topics: Humans; Brain; Central Nervous System; Extracellular Matrix; Organoids; Pluripotent Stem Cells; Prosencephalon; Tissue Culture Techniques; Stem Cells; Morphogenesis
PubMed: 38194967
DOI: 10.1016/j.cell.2023.12.012 -
Cell Reports May 2022The MDM2 oncoprotein antagonizes the tumor suppressor p53 by physical interaction and ubiquitination. However, it also sustains the progression of DNA replication forks,...
The MDM2 oncoprotein antagonizes the tumor suppressor p53 by physical interaction and ubiquitination. However, it also sustains the progression of DNA replication forks, even in the absence of functional p53. Here, we show that MDM2 binds, inhibits, ubiquitinates, and destabilizes poly(ADP-ribose) polymerase 1 (PARP1). When cellular MDM2 levels are increased, this leads to accelerated progression of DNA replication forks, much like pharmacological inhibition of PARP1. Conversely, overexpressed PARP1 restores normal fork progression despite elevated MDM2. Strikingly, MDM2 profoundly reduces the frequency of fork reversal, revealed as four-way junctions through electron microscopy. Depletion of RECQ1 or the primase/polymerase (PRIMPOL) reverses the MDM2-mediated acceleration of the nascent DNA elongation rate. MDM2 also increases the occurrence of micronuclei, and it exacerbates camptothecin-induced cell death. In conclusion, high MDM2 levels phenocopy PARP inhibition in modulation of fork restart, representing a potential vulnerability of cancer cells.
Topics: DNA; DNA Damage; DNA Primase; DNA Replication; Tumor Suppressor Protein p53
PubMed: 35649362
DOI: 10.1016/j.celrep.2022.110879 -
The Journal of Clinical Investigation Sep 2022Myelodysplastic syndromes (MDS) are age-related myeloid neoplasms with increased risk of progression to acute myeloid leukemia (AML). The mechanisms of transformation of...
Myelodysplastic syndromes (MDS) are age-related myeloid neoplasms with increased risk of progression to acute myeloid leukemia (AML). The mechanisms of transformation of MDS to AML are poorly understood, especially in relation to the aging microenvironment. We previously established an mDia1/miR-146a double knockout (DKO) mouse model phenocopying MDS. These mice develop age-related pancytopenia with oversecretion of proinflammatory cytokines. Here, we found that most of the DKO mice underwent leukemic transformation at 12-14 months of age. These mice showed myeloblast replacement of fibrotic bone marrow and widespread leukemic infiltration. Strikingly, depletion of IL-6 in these mice largely rescued the leukemic transformation and markedly extended survival. Single-cell RNA sequencing analyses revealed that DKO leukemic mice had increased monocytic blasts that were reduced with IL-6 knockout. We further revealed that the levels of surface and soluble IL-6 receptor (IL-6R) in the bone marrow were significantly increased in high-risk MDS patients. Similarly, IL-6R was also highly expressed in older DKO mice. Blocking of IL-6 signaling significantly ameliorated AML progression in the DKO model and clonogenicity of CD34-positive cells from MDS patients. Our study establishes a mouse model of progression of age-related MDS to AML and indicates the clinical significance of targeting IL-6 signaling in treating high-risk MDS.
Topics: Animals; Bone Marrow; Interleukin-6; Leukemia, Myeloid, Acute; Mice; Myelodysplastic Syndromes; Signal Transduction; Tumor Microenvironment
PubMed: 35900794
DOI: 10.1172/JCI152673 -
Neuronal Signaling Sep 2023Mutations in the leucine-rich repeat kinase 2 () gene are associated with familial and sporadic forms of Parkinson's disease (PD). Sporadic PD and LRRK2 PD share main... (Review)
Review
Mutations in the leucine-rich repeat kinase 2 () gene are associated with familial and sporadic forms of Parkinson's disease (PD). Sporadic PD and LRRK2 PD share main clinical and neuropathological features, namely hypokinesia, degeneration of nigro-striatal dopamine neurons and α-synuclein aggregates in the form of Lewy bodies. Animals harboring the most common LRRK2 mutations, i.e. p.G2019S and p.R1441C/G, have been generated to replicate the parkinsonian phenotype and investigate the underlying pathogenic mechanisms. Disappointingly, however, LRRK2 rodents did not consistently phenocopy hypokinesia and nigro-striatal degeneration, or showed Lewy body-like aggregates. Instead, LRRK2 rodents manifested non-motor signs and dysregulated transmission at dopaminergic and non-dopaminergic synapses that are reminiscent of behavioral and functional network changes observed in the prodromal phase of the disease. LRRK2 rodents also manifested greater susceptibility to different parkinsonian toxins or stressors when subjected to dual-hit or multiple-hit protocols, confirming LRRK2 mutations as genetic risk factors. In conclusion, LRRK2 rodents represent a unique tool to identify the molecular mechanisms through which LRRK2 modulates the course and clinical presentations of PD and to study the interplay between genetic, intrinsic and environmental protective/risk factors in PD pathogenesis.
PubMed: 37601008
DOI: 10.1042/NS20220040