👤 Murali Nagarajan

Disruption of metabolic interactions between astrocytes and neurons, in particular of the lactate shuttle, may contribute to neurodevelopmental and psychiatric disorders such as autism spectrum disorder (ASD) and schizophrenia. The enzyme glycine decarboxylase (GLDC), predominantly expressed in astrocytes, degrades glycine and plays a critical role in regulating NMDA receptor function and cellular metabolism. Here, we investigated whether administration of lactate would reverse schizophrenia-like phenotypes in a mouse model for psychosis with 4 copies of the Gldc gene (4cG mice). Adult male and female 4cG and wildtype mice were subjected to acute L-lactate intraperitoneal administration one hour before behavioral testing and brain collection for biochemical assays. Y-maze spontaneous alternation test, prepulse inhibition of acoustic startle test, and the three-chamber social interaction test were performed for behavioral analysis, and Western blots for protein estimations. In 4cG mice, acute lactate administration one hour before assessment rescued short-term memory deficits, acoustic startle habituation deficits, and normalized deficits in social preference behavior. Furthermore, lactate treatment restored the expression of PGC1α, a master regulator of mitochondrial biogenesis, and brain-derived neurotrophic factor (BDNF), a protein essential for synaptic plasticity. The results suggest a role for astrocytic metabolism in modulating neuronal function, and potential molecular mechanisms underlying the reversal of behavioral phenotypes. The results indicate that exogenous lactate may reverse key pathophysiological and behavioral deficits in a mouse model for schizophrenia and that lactate supplementation may be useful as a therapeutic strategy for schizophrenia and related disorders. Show less

Alzheimer's disease (AD) is a complex and progressive brain disorder marked by memory loss, cognitive decline, and behavioral changes. One of its defining features is the build-up of amyloid plaques, clumps of β-amyloid (Aβ) peptides, in the brain, along with the formation of neurofibrillary tangles. These Aβ peptides are generated when the amyloid precursor protein (APP) is cleaved by enzymes, with β-secretase (BACE1) playing a key role in the first step of this process. Because BACE1 starts the cascade that leads to harmful Aβ build-up, it has become an important target in the search for effective Alzheimer's treatments. As Aβ accumulates in neurons, it disrupts communication between brain cells and triggers oxidative stress, which worsens damage and accelerates disease progression. This is often exacerbated by imbalances in metal ions, such as copper and iron. While tacrine, an early acetylcholinesterase inhibitor, has shown benefits in managing AD symptoms, its limitations have led researchers to explore improved versions. One promising direction is the development of tacrine-based hybrid molecules. By combining tacrine with other chemical groups that have anti-β-amyloid (Aβ) effects, antioxidant properties, and metal-chelating properties, scientists aim to create compounds that target multiple aspects of the disease simultaneously. This review examines the emerging potential of tacrine hybrids, particularly their capacity to inhibit BACE1 and prevent Aβ aggregation, providing new hope for more effective and disease-modifying therapies for Alzheimer's disease. Show less

Preeclampsia (PE), a severe hypertensive disorder of pregnancy, is associated with circadian rhythm disruption, but the underlying placental molecular networks remain poorly understood. This study aimed to identify key hub genes, regulatory pathways, and novel biomarkers at the intersection of Early-Onset PE (EOPE) and the placental circadian clock. The placental transcriptomic dataset GSE114691 (20 EOPE vs. 20 gestational age-matched preterm controls) was analyzed to identify differentially expressed circadian genes (DECGs). Hub genes were prioritized via protein-protein interaction (PPI) networks. Hub gene expression was validated using effect size (Cohen's d) analysis, and diagnostic performance was evaluated using Receiver Operating Characteristic (ROC) curve analysis. An upstream TF-miRNA co-regulatory network and drug-gene interactions were also analyzed. This pipeline identified 33 DECGs and 10 central hub genes (TGFB1, SPP1, ENG, CD63, SNAI1, GPT2, APLN, EZR, NTRK2, and GLUD1), all significantly dysregulated in EOPE. Crucially, analysis of the core clock machinery revealed a specific uncoupling of the regulatory feedback loop. ROC analysis revealed exceptional diagnostic potential. Notably, NTRK2 emerged as a novel, near-perfect classifier (Area Under the Curve [AUC] = 0.99), outperforming the established marker ENG (AUC = 0.97). Upstream analysis identified key transcription factors (FOXC1, GATA2), and drug-gene analysis revealed clinically relevant interactions between TGFB1 and the chronotherapeutic agents melatonin and aspirin. This study provides a systems-level map of the disrupted placental circadian network in EOPE. Our findings suggest that circadian misalignment is a central feature of placental pathology, offering a molecular rationale for developing novel chronotherapeutic strategies. Show less

A large fraction of the genome interacts with the nuclear periphery through lamina-associated domains (LADs), repressive regions which play an important role in genome organization and gene regulation across development. Despite much work, LAD structure and regulation are not fully understood, and a mounting number of studies have identified numerous genetic and epigenetic differences within LADs, demonstrating they are not a uniform group. Here, we profile lamin B1, CBX1 (also known as HP1B), H3K9me3, H3K9me2, H3K27me3, H3K14ac, H3K27ac, and H3K9ac in MEF cell lines derived from the same mouse colony, and cluster LADs based on the abundance and distribution of these features across LADs. We find that LADs fall into three groups, each enriched in a unique set of histone modifications and genomic features. Each group is defined by a different heterochromatin modification (H3K9me3, H3K9me2, or H3K27me3), suggesting that all three of these marks play important roles in regulation of LAD chromatin and potentially of lamina association. We also discover unique features of LAD borders, including a LAD border-specific enrichment of H3K14ac. These results reveal important distinctions between LADs and highlight the rich diversity and complexity in LAD structure and regulatory mechanisms. Show less

Merkel cell carcinomas (MCCs) exhibit diverse molecular profiles, often categorized by their association with Merkel cell polyoma virus (MCPyV). MCPyV-associated MCCs typically display a low tumor mutational burden (TMB), lacking both somatic mutations and ultraviolet signature. By contrast, MCPyV-negative MCCs commonly arise in sun-exposed skin and frequently exhibit a high TMB, along with TERT promoter mutation (TPM) and somatic mutations, particularly in TP53 and RB1 . Gene fusions are exceedingly rare in MCCs, and their specific frequency and fusion transcripts remain largely unexplored. Here, we present a unique case of MCPyV-associated MCC characterized by NSD3::FGFR1 fusion, representing a novel fusion transcript not previously reported in MCCs. A 72-year-old White man presented with a cyst-like nodule on the left elbow, which had progressively increased in size over a span of 6 months. Excisional biopsy specimen revealed a neuroendocrine carcinoma diffusely expressing CK20 (perinuclear dot-like), synaptophysin, CD56, NSE, and MCPyV, consistent with MCC. Next-generation sequencing identified a NSD3::FGFR1 fusion without any additional somatic mutations, including TP53 and RB1 mutations, or TPM. Although NSD3::FGFR1 fusion has been sporadically reported in other solid tumors, such as pulmonary squamous cell carcinoma, its identification in an MCC is unprecedented to our knowledge. This novel finding not only underscores the uniqueness of our case but also contributes to the evolving understanding of the molecular landscape of MCCs, particularly MCPyV-associated MCCs. Show less

The poultry industry is significantly impacted by viral infections, particularly Newcastle Disease Virus (NDV), which leads to substantial economic losses. It is essential to comprehend how the sequence of development affects biological pathways and how early exposure to infections might affect immune responses. This study employed transcriptome analysis to investigate host-pathogen interactions by analyzing gene expression changes in NDV-infected chicken embryos' lungs. RNA-Seq reads were aligned with the chicken reference genome (Galgal7), revealing 594 differentially expressed genes: 264 upregulated and 330 downregulated. The most overexpressed genes, with logFC between 8.15 and 8.75, included C8A, FGG, PIT54, FETUB, APOC3, and FGA. Notably, downregulated genes included BPIFB3 (-4.46 logFC) and TRIM39.1 (-4.26 logFC). The analysis also identified 29 novel transcripts and 20 lncRNAs that were upregulated. Gene Ontology and KEGG pathways' analyses revealed significant alterations in gene expression related to immune function, metabolism, cell cycle, nucleic acid processes, and mitochondrial activity due to NDV infection. Key metabolic genes, such as ALDOB (3.27 logFC), PRPS2 (2.66 logFC), and XDH (2.15 logFC), exhibited altered expression patterns, while DCK2 (-1.99 logFC) and TK1 (-2.11 logFC) were also affected. Several immune-related genes showed significant upregulation in infected lung samples, including ALB (6.15 logFC), TLR4 (1.86 logFC), TLR2 (2.79 logFC), and interleukin receptors, such as IL1R2 (3.15 logFC) and IL22RA2 (1.37 logFC). Conversely, genes such as CXCR4 (-1.49 logFC), CXCL14 (-2.57 logFC), GATA3 (-1.51 logFC), and IL17REL (-2.93 logFC) were downregulated. The higher expression of HSP genes underscores their vital role in immune responses. Comprehension of these genes' interactions is essential for regulating viral replication and immune responses during infections, potentially aiding in the identification of candidate genes for poultry breed improvement amidst NDV challenges. Show less

The N-acyl-L-homoserine lactone (AHL) quorum sensing regulates virulence in the opportunistic pathogen, Pseudomonas aeruginosa. The LasI and RhlI AHL synthases use acyl carrier protein substrates to synthesize, respectively, the 3-oxododecanoyl-L-homoserine lactone (3-oxoC12-HSL) and butyryl-L-homoserine lactone (C4-HSL) QS signals for this bacterium. Although P. aeruginosa genome contains three open reading frames to encode three acyl carrier proteins, namely the ACP Show less