Expansion and mechanistic insights into de novo DEAF1 variants in DEAF1-associated neurodevelopmental disorders

De novo deleterious and heritable biallelic mutations in the DNA binding domain (DBD) of the transcription factor deformed epidermal autoregulatory factor 1 (DEAF1) result in a phenotypic spectrum of disorders termed DEAF1-associated neurodevelopmental disorders (DAND). RNA-sequencing using hippocampal RNA from mice with conditional deletion of Deaf1 in the central nervous system indicate that loss of Deaf1 activity results in the altered expression of genes involved in neuronal function, dendritic spine maintenance, development, and activity, with reduced dendritic spines in hippocampal regions. Since DEAF1 is not a dosage-sensitive gene, we assessed the dominant negative activity of previously identified de novo variants and a heritable recessive DEAF1 variant on selected DEAF1-regulated genes in 2 different cell models. While no altered gene expression was observed in cells over-expressing the recessive heritable variant, the gene expression profiles of cells over-expressing de novo variants resulted in similar gene expression changes as observed in CRISPR-Cas9-mediated DEAF1-deleted cells. Altered expression of DEAF1-regulated genes was rescued by exogenous expression of WT-DEAF1 but not by de novo variants in cells lacking endogenous DEAF1. De novo heterozygous variants within the DBD of DEAF1 were identified in 10 individuals with a phenotypic spectrum including autism spectrum disorder, developmental delays, sleep disturbance, high pain tolerance, and mild dysmorphic features. Functional assays demonstrate these variants alter DEAF1 transcriptional activity. Taken together, this study expands the clinical phenotypic spectrum of individuals with DAND, furthers our understanding of potential roles of DEAF1 on neuronal function, and demonstrates dominant negative activity of identified de novo variants.

A subpopulation of oxytocin neurons initiate expression of CRF receptor 1 (CRFR1) in females post parturition

Oxytocin (OT) is essential for successful reproduction, particularly during parturition and lactation. During the postpartum period, OT also influences maternal behavior to promote bonding between mothers and their newborns, and increases stress resilience. However, the mechanism by which stress influences OT neuron activity and OT release has remained unclear. Here, we provide evidence that a subpopulation of OT neurons initiate expression of the receptor for the stress neuropeptide Corticotropin Releasing Factor (CRF), CRFR1, in reproductive females. OT neuron expression of CRFR1 begins at the first parturition and increases during the postpartum period until weaning. The percentage of OT neurons that express CRFR1 increases with successive breeding cycles until it reaches a plateau of 20-25% of OT neurons. OT neuron expression of CRFR1 in reproductive females is maintained after they are no longer actively breeding. CRFR1 expression leads to activation of OT neurons when animals are stressed. We propose a model in which direct CRF signaling to OT neurons selectively in reproductive females potentiates OT release to promote stress resilience in mothers.

Generation of a CRF1-Cre transgenic rat and the role of central amygdala CRF1 cells in nociception and anxiety-like behavior

Corticotropin-releasing factor type-1 (CRF1) receptors are critical to stress responses because they allow neurons to respond to CRF released in response to stress. Our understanding of the role of CRF1-expressing neurons in CRF-mediated behaviors has been largely limited to mouse experiments due to the lack of genetic tools available to selectively visualize and manipulate CRF1+ cells in rats. Here, we describe the generation and validation of a transgenic CRF1-Cre-tdTomato rat. We report that Crhr1 and Cre mRNA expression are highly colocalized in both the central amygdala (CeA), composed of mostly GABAergic neurons, and in the basolateral amygdala (BLA), composed of mostly glutamatergic neurons. In the CeA, membrane properties, inhibitory synaptic transmission, and responses to CRF bath application in tdTomato+ neurons are similar to those previously reported in GFP+ cells in CRFR1-GFP mice. We show that stimulatory DREADD receptors can be targeted to CeA CRF1+ cells via virally delivered Cre-dependent transgenes, that transfected Cre/tdTomato+ cells are activated by clozapine-n-oxide in vitro and in vivo, and that activation of these cells in vivo increases anxiety-like and nocifensive behaviors. Outside the amygdala, we show that Cre-tdTomato is expressed in several brain areas across the brain, and that the expression pattern of Cre-tdTomato cells is similar to the known expression pattern of CRF1 cells. Given the accuracy of expression in the CRF1-Cre rat, modern genetic techniques used to investigate the anatomy, physiology, and behavioral function of CRF1+ neurons can now be performed in assays that require the use of rats as the model organism.

Bacterial endophytome-mediated resistance in banana for the management of Fusarium wilt

Banana (Musa spp.), a major cash and staple fruit crop in many parts of the world, is infected by Fusarium wilt, which contributes up to 100% yield loss and causes social consequences. Race 1 and race 2 of Panama wilt caused by Fusarium oxysporum f. sp. cubense (Foc) are prevalent worldwide and seriously affect many traditional varieties. The threat of Foc tropical race 4 (Foc TR4) is looming large in African counties. However, its incidence in India has been confined to Bihar (Katihar and Purnea), Uttar Pradesh (Faizabad), Madhya Pradesh (Burhanpur) and Gujarat (Surat). Management of Foc races by employing fungicides is often not a sustainable option as the disease spread is rapid and they negatively alter the biodiversity of beneficial ectophytes and endophytes. Besides, soil drenching with carbendazim/trifloxystrobin + tebuconazole is also not effective in suppressing the Fusarium wilt of banana. Improvement of resistance to Fusarium wilt in susceptible cultivars is being addressed through both conventional and advanced breeding approaches. However, engineering of banana endosphere with bacterial endophytes from resistant genotypes like Pisang lilly and YKM5 will induce the immune response against Foc, irrespective of races. The composition of the bacterial endomicrobiome in different banana cultivars is dominated by the phyla Proteobacteria, Bacteroidetes and Actinobacteria. The major bacterial endophytic genera antagonistic to Foc are Bacillus, Brevibacillus, Paenibacillus, Virgibacillus, Staphylococcus, Cellulomonas, Micrococcus, Corynebacterium, Kocuria spp., Paracoccus sp., Acinetobacter spp. Agrobacterium, Aneurinibacillus, Enterobacter, Klebsiella, Lysinibacillus, Micrococcus, Rhizobium, Sporolactobacillus, Pantoea, Pseudomonas, Serratia, Microbacterium, Rhodococcus, Stenotrophomonas, Pseudoxanthomonas, Luteimonas, Dokdonella, Rhodanobacter, Luteibacter, Steroidobacter, Nevskia, Aquicella, Rickettsiella, Legionella, Tatlockia and Streptomyces. These bacterial endophytes promote the growth of banana plantlets by solubilising phosphate, producing indole acetic acid and siderophores. Application of banana endophytes during the hardening phase of tissue-cultured clones serves as a shield against Foc. Hitherto, MAMP molecules of endophytes including flagellin, liposaccharides, peptidoglycans, elongation factor, cold shock proteins and hairpins induce microbe-associated molecular pattern (MAMP)-triggered immunity to suppress plant pathogens. The cascade of events associated with ISR and SAR is induced through MAPK and transcription factors including WRKY and MYC. Studies are underway to exploit the potential of antagonistic bacterial endophytes against Foc isolates and to develop an understanding of the MAMP-triggered immunity and metabolomics cross talk modulating resistance. This review explores the possibility of harnessing the potential bacterial endomicrobiome against Foc and developing nanoformulations with bacterial endophytes for increased efficacy against lethal pathogenic races of Foc infecting banana.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-021-02833-5.

Dissociable Roles of Pallidal Neuron Subtypes in Regulating Motor Patterns

We have previously established that PV+ neurons and Npas1+ neurons are distinct neuron classes in the external globus pallidus (GPe): they have different topographical, electrophysiological, circuit, and functional properties. Aside from Foxp2+ neurons, which are a unique subclass within the Npas1+ class, we lack driver lines that effectively capture other GPe neuron subclasses. In this study, we examined the utility of Kcng4-Cre, Npr3-Cre, and Npy2r-Cre mouse lines (both males and females) for the delineation of GPe neuron subtypes. By using these novel driver lines, we have provided the most exhaustive investigation of electrophysiological studies of GPe neuron subtypes to date. Corroborating our prior studies, GPe neurons can be divided into two statistically distinct clusters that map onto PV+ and Npas1+ classes. By combining optogenetics and machine learning-based tracking, we showed that optogenetic perturbation of GPe neuron subtypes generated unique behavioral structures. Our findings further highlighted the dissociable roles of GPe neurons in regulating movement and anxiety-like behavior. We concluded that Npr3+ neurons and Kcng4+ neurons are distinct subclasses of Npas1+ neurons and PV+ neurons, respectively. Finally, by examining local collateral connectivity, we inferred the circuit mechanisms involved in the motor patterns observed with optogenetic perturbations. In summary, by identifying mouse lines that allow for manipulations of GPe neuron subtypes, we created new opportunities for interrogations of cellular and circuit substrates that can be important for motor function and dysfunction.SIGNIFICANCE STATEMENT Within the basal ganglia, the external globus pallidus (GPe) has long been recognized for its involvement in motor control. However, we lacked an understanding of precisely how movement is controlled at the GPe level as a result of its cellular complexity. In this study, by using transgenic and cell-specific approaches, we showed that genetically-defined GPe neuron subtypes have distinct roles in regulating motor patterns. In addition, the in vivo contributions of these neuron subtypes are in part shaped by the local, inhibitory connections within the GPe. In sum, we have established the foundation for future investigations of motor function and disease pathophysiology.

Understanding the molecular basis on the biological suppression of bacterial leaf blight of anthurium exerted by Bacillus subtilis (BIO3) through proteomic approach

We attempted to study the antibacterial activity of rhizospheric Bacillus spp., to curb the bacterial blight of anthurium caused by Xanthomonas axonopodis pv. dieffenbachiae (Xad). Twenty-eight bacterial isolates from rhizospheric regions were identified as different Bacillus spp. and Ochrobactrum sp. using 16S rRNA gene sequencing. B. subtilis BIO3 effectively inhibited the growth of Xad up to 1450.7 mm², and extracted volatile organic metabolites from the isolate BIO3 inhibited the growth of Xad up to 1024 mm². Tritrophic interaction of anthurium leaves bacterized with B. subtilis BIO3 and challenged with Xad resulted in the expression of 12 unique proteins compared to untreated control. Mascot Peptide Mass Fingerprint-based identification indicated that one was glutathione peroxidase, involved in defence mechanism, other six proteins were identified as leghemoglobin II, CTP synthase-like, predicted protein (Physcomitrella patens), centromere-associated protein E, grain size protein, and five proteins were hypothetical proteins. Foliar application with 1% liquid formulations (10⁸ CFU/ml) of B. subtilis BIO3 significantly suppressed the bacterial leaf blight of anthurium up to 78% over untreated control and also increased the stem length and flower yield.

Flagellin of Bacillus amyloliquefaciens works as a resistance inducer against groundnut bud necrosis virus in chilli (Capsicum annuum L.)

Groundnut bud necrosis virus (GBNV), a member of the genus Tospovirus, has an extensive host range and is associated with necrosis disease of chilli (Capsicum annuum L.), which is a major threat to commercial production. Plant growth promoting rhizobacteria (PGPR) have been investigated for their antiviral activity in several crops and for their potential use in viral disease management. However, the microbial mechanisms associated with PGPR in triggered immunity against plant viruses have rarely been studied. To understand the innate immune responses activated by Bacillus spp. against GBNV, we studied microbe-associated molecular pattern (MAMP) triggered immunity (MTI) in chilli using transient expression of the flagellin gene of Bacillus amyloliquefaciens CRN9 from Agrobacterium clones, which also induced the expression of EAS1 gene transcripts coding for epi-aristolochene synthase, which is responsible for the accumulation of capsidiol phytoalexin. In addition, the transcript levels of WRKY33 transcription factor and salicylic acid (SA)-responsive defense genes such as NPR1, PAL, PO and SAR8.2 were increased. Jasmonate (JA)-responsive genes, viz., PDF, and LOX genes, were also upregulated in chilli plants challenged with GBNV. Further analysis revealed significant induction of these genes in chilli plants treated with B. amyloliquefaciens CRN9 and benzothiadiazole (BTH). The transcript levels of defense response genes and pathogenesis-related proteins were significantly higher in plants treated with Bacillus and BTH and remained significantly higher at 72 h post-inoculation and compared to the inoculated control. The plants treated with flagellin using the agrodrench method and exogenous treatment with B. amyloliquefaciens and BTH showed resistance to GBNV upon mechanical inoculation and a reduced virus titre which was confirmed by qPCR assays. Thus, transient expression of flagellin, a MAMP molecule from B. amyloliquefaciens CRN9, is able to trigger innate immunity and restrain virus growth in chilli via induced systemic resistance (ISR) activated by both the SA and JA/ET signalling pathways.

CRF signaling between neurons in the paraventricular nucleus of the hypothalamus (PVN) coordinates stress responses

The importance of a precisely coordinated neuroendocrine, autonomic, and behavioral stress response was a primary theme at the Stress Neurobiology Workshop 2018, held in the beautiful setting of Banff Provincial Park in Alberta, Canada. Much of the research featured at this meeting reinforced the importance of appropriately responding to stress in order to avoid various neuropsychiatric pathologies, including Post-Traumatic Stress Disorder (PTSD), depression, and addiction. Corticotropin-Releasing Factor (CRF) neurons in the paraventricular nucleus of the hypothalamus (PVN) are central players in the stress response, integrating both external and visceral stress-relevant information, then directing neuroendocrine, autonomic and behavioral adaptations via endocrine and neural outputs of the PVN. The PVN contains a densely packed array of neuron types that respond to stress, including CRF neurons that activate the Hypothalamic-Pituitary-Adrenal (HPA) axis. Recently, identification of a new population of neurons in the PVN that express CRF Receptor 1 (CRFR1) has suggested that CRF release in the PVN signals to neighboring CRF responsive neurons, potentially functioning in HPA axis feedback, neuroendocrine coordination, and autonomic signaling. Here, we review our recent work characterizing an intra-PVN microcircuit in which locally released CRF release activates CRFR1+ neurons that make recurrent inhibitory GABAergic synapses onto CRF neurons to dampen excitability , therebylimiting HPA axis hyperactivity in response to stress and promoting stress recovery, which we presented in a poster session at the conference. We then discuss questions that have arisen following publication of our initial characterization of the microcircuit, regarding specific features of intra-PVN CRF signaling and its potential role in coordinating neuroendocrine, autonomic, and behavioral outputs of the PVN. Our presented work, as well as many of the presentations at the Stress Neurobiology Workshop 2018 together establish intra-PVN signaling as an important regulatory node in stress response pathways, which are central to the pathogenesis of neuropsychiatric disorders.

Paraventricular hypothalamic and amygdalar CRF neurons synapse in the external globus pallidus

Stress evokes directed movement to escape or hide from potential danger. Corticotropin-releasing factor (CRF) neurons are highly activated by stress; however, it remains unclear how this activity participates in stress-evoked movement. The external globus pallidus (GPe) expresses high levels of the primary receptor for CRF, CRFR1, suggesting the GPe may serve as an entry point for stress-relevant information to reach basal ganglia circuits, which ultimately gate motor output. Indeed, projections from CRF neurons are present within the GPe, making direct contact with CRFR1-positive neurons. CRFR1 expression is heterogenous in the GPe; prototypic GPe neurons selectively express CRFR1, while arkypallidal neurons do not. Moreover, CRFR1-positive GPe neurons are excited by CRF via activation of CRFR1, while nearby CRFR1-negative neurons do not respond to CRF. Using monosynaptic rabies viral tracing techniques, we show that CRF neurons in the stress-activated paraventricular nucleus of the hypothalamus (PVN), central nucleus of the amygdala (CeA), and bed nucleus of the stria terminalis (BST) make synaptic connections with CRFR1-positive neurons in the GPe an unprecedented circuit connecting the limbic system with the basal ganglia. CRF neurons also make synapses on Npas1 neurons, although the majority of Npas1 neurons are arkypallidal and do not express CRFR1. Interestingly, prototypic and arkypallidal neurons receive different patterns of innervation from CRF-rich nuclei. Hypothalamic CRF neurons preferentially target prototypic neurons, while amygdalar CRF neurons preferentially target arkypallidal neurons, suggesting that these two inputs to the GPe may have different impacts on GPe output. Together, these data describe a novel neural circuit by which stress-relevant information carried by the limbic system signals in the GPe via CRF to influence motor output.

Abstract P6-06-04: Targeting replication stress in triple negative breast cancer treatment regimen: An emerging approach

Triple-negative breast cancers (TNBCs) represent aggressive heterogeneous subtype of breast cancer with poor clinical outcome. TNBCs have been reported to have high levels of replication stress due to i) various oncogene activations (C-myc or EGFR) ii) germline BRCA mutations iii) “BRCAness” in the absence of BRCA mutations in sporadic TNBCs. Replication stress is known to cause genomic instability, promote tumorigenesis and plays a critical role in therapy resistance in TNBCs. Therefore, targeting replication stress has emerged as an effective approach for better TNBC treatment through further downregulation of the remaining checkpoints to induce catastrophic failure of TNBC cells proliferation. Herein, we evaluated the anticancer efficacy of Carbazole Blue (CB), a synthetic analogue of Carbazole, on TNBC cells growth and progression. Our results demonstrated that CB inhibits short and long term viability of TNBC (MDA-MB-231, MDA-MB-468 and BT549) cells in a dose dependent manner without affecting normal mammary epithelial (MCF-10A) cells. In addition, CB treatment significantly reduced proliferation of TNBC cells, as evidenced by the BrdU proliferation assay. Consistent with this, our results further demonstrated that CB treatment induced G1/S cell cycle arrest and apoptosis in TNBCs. Importantly, systemic delivery of CB using nanoparticle-based delivery approach suppressed breast cancer growth without inducing toxicity, in preclinical orthotopic xenograft and PDX mouse models of TNBC. Furthermore, our gene microarray analysis revealed that CB treatment modulates the expression and activity of several genes known to be involved in DNA replication (CDC6, CDT1, MCMs, Claspin, POLE and PCNA) and associated DNA repair machinery such as (XRCC3, Exo1 and RAD51), which play pivotal roles in replication stress. Our results for the first time highlight the potential use of CB as a novel and potent therapeutic agent for treating TNBCs. As exploiting replication stress to treat cancer is gaining major interest, compound/s that may induce replication stress and inhibit DNA repair ability of cancer cells, has immense translational potential.

Citation Format: Rajamanickam S, Park JH, Bates K, Timilsina S, Eedunuri VK, Onyeagucha B, Subbarayalu P, Abdelfattah N, Jung KH, Favours E, Mohammad TA, Chen H-IH, Vadlamudi RK, Chen Y, Kaipparettu BA, Arbiser JL, Rao MK. Targeting replication stress in triple negative breast cancer treatment regimen: An emerging approach [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-06-04.

Abstract P4-07-06: Imipramine Blue - A safe and potent therapeutic regimen that suppresses breast cancer growth and progression by targeting DNA damage surveillance pathway

Despite improvement in overall survival of breast cancer patients, many women don't survive this disease. Moreover, the quality of life for patients who do survive is often substantially reduced due to the toxicity associated with the chemotherapy. Here, we report that imipramine blue (IB), a novel analogue of anti-depressant imipramine that we recently synthesized, may serve as a safe and potent therapeutic agent for treating breast cancers. We show that IB reduced cell growth, migration and invasion of breast cancer cells. Systemic delivery of IB using nanoparticle-based drug delivery approach suppressed breast cancer growth and metastasis without inducing any toxicity in pre-clinical orthotropic mouse models. Notably, using ex-vivo model of tumor explants from breast cancer patients, we demonstrated that IB inhibited breast cancer growth without affecting normal mammary epithelial cell proliferation. Furthermore, IB improved the sensitivity of breast cancer cells to chemotherapy drugs paclitaxel and doxorubicin. Our results revealed that IB mediated its anti-tumor effect by targeting genes involved in cell cycle progression, microtubule dynamics and DNA damage surveillance pathway including Forkhead Box M1 (FOXM1), stathmin1, S-phase kinase-associated protein 2 (Skp2) and XRCC3, which we show to be highly expressed in breast cancer patients. Importantly, we demonstrated that IB inhibited breast cancer cell's ability to repair DNA strand breaks by impairing homologous recombination events. These findings highlight the potential of IB to be used as a potent therapeutic regimen for treating breast cancer patients. Since IB-1 is derived from a FDA approved drug it has potential to be rapidly translated to the clinic.

Citation Format: Rajamanickam S, Subbarayalu P, Timilsina S, Gorthi A, Drake MT, Chen Y, Vadlamudi R, Bishop AJR, Arbiser JL, Rao MK. Imipramine Blue - A safe and potent therapeutic regimen that suppresses breast cancer growth and progression by targeting DNA damage surveillance pathway. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-07-06.

DEAF1 binds unmethylated and variably spaced CpG dinucleotide motifs

DEAF1 is a transcriptional regulator associated with autoimmune and neurological disorders and is known to bind TTCG motifs. To further ascertain preferred DEAF1 DNA ligands, we screened a random oligonucleotide library containing an "anchored" CpG motif. We identified a binding consensus that generally conformed to a repeated TTCGGG motif, with the two invariant CpG dinucleotides separated by 6-11 nucleotides. Alteration of the consensus surrounding the dual CpG dinucleotides, or cytosine methylation of a single CpG half-site, eliminated DEAF1 binding. A sequence within the Htr1a promoter that resembles the binding consensus but contains a single CpG motif was confirmed to have low affinity binding with DEAF1. A DEAF1 binding consensus was identified in the EIF4G3 promoter and ChIP assay showed endogenous DEAF1 was bound to the region. We conclude that DEAF1 preferentially binds variably spaced and unmethylated CpG-containing half-sites when they occur within an appropriate consensus.

Mutations affecting the SAND domain of DEAF1 cause intellectual disability with severe speech impairment and behavioral problems

Recently, we identified in two individuals with intellectual disability (ID) different de novo mutations in DEAF1, which encodes a transcription factor with an important role in embryonic development. To ascertain whether these mutations in DEAF1 are causative for the ID phenotype, we performed targeted resequencing of DEAF1 in an additional cohort of over 2,300 individuals with unexplained ID and identified two additional individuals with de novo mutations in this gene. All four individuals had severe ID with severely affected speech development, and three showed severe behavioral problems. DEAF1 is highly expressed in the CNS, especially during early embryonic development. All four mutations were missense mutations affecting the SAND domain of DEAF1. Altered DEAF1 harboring any of the four amino acid changes showed impaired transcriptional regulation of the DEAF1 promoter. Moreover, behavioral studies in mice with a conditional knockout of Deaf1 in the brain showed memory deficits and increased anxiety-like behavior. Our results demonstrate that mutations in DEAF1 cause ID and behavioral problems, most likely as a result of impaired transcriptional regulation by DEAF1.

Papillary thyroid carcinoma: debate at rest

INTRODUCTION

Papillary thyroid cancer (PTC) is the most common well-differentiated cancer of the thyroid and is one of the fastest growing group of cancers probably because of the increased use of ultrasound (HRUSG) in the evaluation of the thyroid in recent years.

MATERIALS AND METHODS

A MEDLINE and OVID database search was performed to collect information on papillary thyroid carcinoma. Recently published consensus guidelines were also used as an additional resource.

CONCLUSIONS

The controversy regarding the extent of thyroidectomy in patients of PTC is relatively settled, with total thyoidectomy being the preferred approach with nodules> 1.5 cm in size. Lymph node (LN) metastases do not seem to affect the overall survival, but they do increase the recurrence rate. It is worthwhile to offer LN dissection at initial surgery if LNs are ultrasonologically diagnosed to harbor malignancy. In experts hands, the rate of recurrent laryngeal nerve injury and hypoparathyroidism is negligible in a neck dissection in initial surgery and remains negligible if carried out in a redo or completion scenario.