Disrupted-in-Schizophrenia-1 is essential for normal hypothalamic-pituitary-interrenal (HPI) axis function

Astrocyte-mediated regulation of BLAWFS1 neurons alleviates risk-assessment deficits in DISC1-N mice

Assessing and responding to threats is vital in everyday life. Unfortunately, many mental illnesses involve impaired risk assessment, affecting patients, families, and society. The brain processes behind these behaviors are not well understood. We developed a transgenic mouse model (disrupted-in-schizophrenia 1 [DISC1]-N) with a disrupted avoidance response in risky settings. Our study utilized single-nucleus RNA sequencing and path-clamp coupling with real-time RT-PCR to uncover a previously undescribed group of glutamatergic neurons in the basolateral amygdala (BLA) marked by Wolfram syndrome 1 (WFS1) expression, whose activity is modulated by adjacent astrocytes. These neurons in DISC1-N mice exhibited diminished firing ability and impaired communication with the astrocytes. Remarkably, optogenetic activation of these astrocytes reinstated neuronal excitability via D-serine acting on BLAWFS1 neurons' NMDA receptors, leading to improved risk-assessment behavior in the DISC1-N mice. Our findings point to BLA astrocytes as a promising target for treating risk-assessment dysfunctions in mental disorders.

Elevated glucocorticoid alters the developmental dynamics of hypothalamic neurogenesis in zebrafish

Exposure to excess glucocorticoid (GC) during early development is implicated in adult dysfunctions. Reduced adult hippocampal neurogenesis is a well-known consequence of exposure to early life stress or elevated GC, however the effects on neurogenesis during development and effects on other brain regions are not well understood. Using an optogenetic zebrafish model, here we analyse the effects of GC exposure on neurogenesis during development in the whole brain. We identify that the hypothalamus is a highly GC-sensitive region where elevated GC causes precocious development. This is followed by failed maturation and early decline accompanied by impaired feeding, growth, and survival. In GC-exposed animals, the developmental trajectory of hypothalamic progenitor cells is strikingly altered, potentially mediated by direct regulation of transcription factors such as rx3 by GC. Our data provide cellular and molecular level insight into GC-induced alteration of the hypothalamic developmental trajectory, a process crucial for health across the life-course.

The Zebrafish Model as a New Discovery Path for Medicinal Plants in the Treatment of Parkinson's Disease

Parkinson's disease (PD) is one of the most frequent degenerative central nervous system disorders affecting older adults. Dopaminergic neuron failure in the substantia nigra is a pathological sign connected with the motor shortfall of PD. Due to their low teratogenic and adverse effect potential, medicinal herbs have emerged as a promising therapy option for preventing and curing PD and other neurodegenerative disorders. However, the mechanism through which natural compounds provide neuroprotection against PD remains unknown. While testing compounds in vertebrates such as mice is prohibitively expensive and time-consuming, zebrafish (Danio rerio) may offer an appealing alternative because they are vertebrates and share many of the same characteristics as humans. Zebrafish are commonly used as animal models for studying many human diseases, and their molecular history and bioimaging properties are appropriate for the study of PD. However, a literature review indicated that only six plants, including Alpinia oxyhylla, Bacopa monnieri, Canavalia gladiate, Centella asiatica, Paeonia suffruticosa, and Stachytarpheta indica had been investigated as potential PD treatments using the zebrafish model. Only C. asiatica and B. monnieri were found to have potential anti-PD activity. In addition to reviewing the current state of research in this field, these plants' putative mechanisms of action against PD are explored, and accessible assays for investigation are made.

Glucocorticoid receptor regulates protein chaperone, circadian clock and affective disorder genes in the zebrafish brain

Glucocorticoid resistance is commonly observed in depression, and has been linked to reduced expression and/or function of the glucocorticoid receptor (NR3C1 in human, hereafter referred to as GR). Previous studies have shown that GR-mutant zebrafish exhibit behavioural abnormalities that are indicative of an affective disorder, suggesting that GR plays a role in brain function. We compared the brain methylomes and brain transcriptomes of adult wild-type and GR-mutant zebrafish, and identified 249 differentially methylated regions (DMRs) that are regulated by GR. These include a cluster of CpG sites within the first intron of fkbp5, the gene encoding the glucocorticoid-inducible heat shock protein co-chaperone Fkbp5. RNA-sequencing analysis revealed that genes associated with chaperone-mediated protein folding, the regulation of circadian rhythm and the regulation of metabolism are particularly sensitive to loss of GR function. In addition, we identified subsets of genes exhibiting GR-regulated transcription that are known to regulate behaviour, and are linked to unipolar depression and anxiety. Taken together, our results identify key biological processes and novel molecular mechanisms through which the GR is likely to mediate responses to stress in the adult zebrafish brain, and they provide further support for the zebrafish GR mutant as a model for the study of affective disorders.

Behavioral analysis through the lifespan of disc1 mutant zebrafish identifies defects in sensorimotor transformation

DISC1 is a genetic risk factor for multiple psychiatric disorders. Compared to the dozens of murine Disc1 models, there is a paucity of zebrafish disc1 models-an organism amenable to high-throughput experimentation. We conducted the longitudinal neurobehavioral analysis of disc1 mutant zebrafish across key stages of life. During early developmental stages, disc1 mutants exhibited abrogated behavioral responses to sensory stimuli across multiple testing platforms. Moreover, during exposure to an acoustic sensory stimulus, loss of disc1 resulted in the abnormal activation of neurons in the pallium, cerebellum, and tectum-anatomical sites involved in the integration of sensory perception and motor control. In adulthood, disc1 mutants exhibited sexually dimorphic reduction in anxiogenic behavior in novel paradigms. Together, these findings implicate disc1 in sensorimotor processes and the genesis of anxiogenic behaviors, which could be exploited for the development of novel treatments in addition to investigating the biology of sensorimotor transformation in the context of disc1 deletion.

Zebrafish as a model to investigate the CRH axis and interactions with DISC1

Release of corticotropin-releasing hormone (CRH) from CRH neurons activates the hypothalamo-pituitary-adrenal (HPA) axis, one of the main physiological stress response systems. Complex feedback loops operate in the HPA axis and understanding the neurobiological mechanisms regulating CRH neurons is of great importance in the context of stress disorders. In this article, we review how in vivo studies in zebrafish have advanced knowledge of the neurobiology of CRH neurons. Disrupted-in-schizophrenia 1 (DISC1) mutant zebrafish have blunted stress responses and can be used to model human stress disorders. We propose that DISC1 influences the development and functioning of CRH neurons as a mechanism linking DISC1 to psychiatric disorders.

Maternal Chronic Ethanol Exposure Decreases Stress Responses in Zebrafish Offspring

In humans, prenatal alcohol exposure can cause serious health issues in children, known collectively as Foetal Alcohol Spectrum Disorders (FASD). Despite the high prevalence of FASD and a lack of effective treatments, the underlying mechanisms causing the teratogenic action of ethanol are still obscure. The limitations of human studies necessitate the use of animal models for identifying the underlying processes, but few studies have investigated the effects of alcohol in the female germline. Here, we used the zebrafish Danio rerio to investigate the effects of chronic (repeated for seven days) exposure to alcohol. Specifically, we tested whether the offspring of females chronically exposed to ethanol during oogenesis exhibited hormonal abnormalities when subjected to a stressor (alarm cue) as larvae, and if they exhibited anxiety-like behaviours as adults. Exposure to alarm cue increased whole-body cortisol in control larvae but not in those of ethanol-treated females. Furthermore, adult offspring of ethanol-treated females showed some reduced anxiety-like behaviours. These findings suggest that the offspring of ethanol-treated females had reduced stress responses. This study is the first to investigate how maternal chronic ethanol exposure prior to fertilisation influences hormonal and behavioural effects in a non-rodent model.

Long lasting anxiety following early life stress is dependent on glucocorticoid signaling in zebrafish

Chronic adversity in early childhood is associated with increased anxiety and a propensity for substance abuse later in adulthood, yet the effects of early life stress (ELS) on brain development remain poorly understood. The zebrafish, Danio rerio, is a powerful model for studying neurodevelopment and stress. Here, we describe a zebrafish model of ELS and identify a role for glucocorticoid signaling during a critical window in development that leads to long-term changes in brain function. Larval fish subjected to chronic stress in early development exhibited increased anxiety-like behavior and elevated glucocorticoid levels later in life. Increased stress-like behavior was only observed when fish were subjected to ELS within a precise time window in early development, revealing a temporal critical window of sensitivity. Moreover, enhanced anxiety-like behavior only emerges after two months post-ELS, revealing a developmentally specified delay in the effects of ELS. ELS leads to increased levels of baseline cortisol, and resulted in a dysregulation of cortisol receptors' mRNA expression, suggesting long-term effects on cortisol signaling. Together, these findings reveal a 'critical window' for ELS to affect developmental reprogramming of the glucocorticoid receptor pathway, resulting in chronic elevated stress.

Larval Zebrafish as a Model for Mechanistic Discovery in Mental Health

Animal models are essential for the discovery of mechanisms and treatments for neuropsychiatric disorders. However, complex mental health disorders such as depression and anxiety are difficult to fully recapitulate in these models. Borrowing from the field of psychiatric genetics, we reiterate the framework of 'endophenotypes' - biological or behavioral markers with cellular, molecular or genetic underpinnings - to reduce complex disorders into measurable behaviors that can be compared across organisms. Zebrafish are popular disease models due to the conserved genetic, physiological and anatomical pathways between zebrafish and humans. Adult zebrafish, which display more sophisticated behaviors and cognition, have long been used to model psychiatric disorders. However, larvae (up to 1 month old) are more numerous and also optically transparent, and hence are particularly suited for high-throughput screening and brain-wide neural circuit imaging. A number of behavioral assays have been developed to quantify neuropsychiatric phenomena in larval zebrafish. Here, we will review these assays and the current knowledge regarding the underlying mechanisms of their behavioral readouts. We will also discuss the existing evidence linking larval zebrafish behavior to specific human behavioral traits and how the endophenotype framework can be applied. Importantly, many of the endophenotypes we review do not solely define a diseased state but could manifest as a spectrum across the general population. As such, we make the case for larval zebrafish as a promising model for extending our understanding of population mental health, and for identifying novel therapeutics and interventions with broad impact.

Polysialylation in a DISC1 Mutant Mouse

Schizophrenia is a serious psychiatric disorder that affects the social life of patients. Psychiatric disorders are caused by a complex combination of genetic (G) and environmental (E) factors. Polysialylation represents a unique posttranslational modification of a protein, and such changes in neural cell adhesion molecules (NCAMs) have been reported in postmortem brains from patients with psychiatric disorders. To understand the G × E effect on polysialylated NCAM expression, in this study, we performed precise measurements of polySia and NCAM using a disrupted-in-schizophrenia 1 (DISC1)-mutant mouse (G), a mouse model of schizophrenia, under acute stress conditions (E). This is the first study to reveal a lower number and smaller length of polySia in the suprachiasmatic nucleus of DISC1 mutants relative to those in wild-type (WT) mice. In addition, an analysis of polySia and NCAM responses to acute stress in five brain regions (olfactory bulb, prefrontal cortex, suprachiasmatic nucleus, amygdala, and hippocampus) revealed that the pattern of changes in these responses in WT mice and DISC1 mutants differed by region. These differences could indicate the vulnerability of DISC1 mutants to stress.

Neural correlates of state transitions elicited by a chemosensory danger cue

BACKGROUND

Detection of predator cues changes the brain state in prey species and helps them avoid danger. Dysfunctionality in changing the central state appropriately in stressful situations is proposed to be an underlying cause of multiple psychiatric disorders in humans.

METHODS

Here, we investigate the dynamics of neural circuits mediating response to a threat, to characterize these states and to identify potential control networks. We use resonant scanning 2-photon microscopy for in vivo brain-wide imaging and custom designed behavioral assays for the study.

RESULTS

We first show that 5-7 day old zebrafish larvae react to an alarm pheromone (Schreckstoff) with reduced mobility. They subsequently display heightened vigilance, as evidenced by increased dark avoidance. Calcium imaging indicates that exposure to Schreckstoff elicits stimulus-locked activity in olfactory sensory neurons innervating a lateral glomerulus and in telencephalic regions including the putative medial amygdala and entopeduncular nucleus. Sustained activity outlasting the stimulus delivery was detected in regions regulating neuromodulator release, including the lateral habenula, posterior tuberculum, superior raphe, and locus coeruleus.

CONCLUSION

We propose that these latter regions contribute to the network that defines the "threatened" state, while neurons with transient activity serve as the trigger. Our study highlights the utility of the zebrafish larval alarm response system to examine neural circuits during stress dependent brain state transitions and to discover potential therapeutic agents when such transitions are disrupted.

The Effects of Early Life Stress on the Brain and Behaviour: Insights From Zebrafish Models

The early life period represents a window of increased vulnerability to stress, during which exposure can lead to long-lasting effects on brain structure and function. This stress-induced developmental programming may contribute to the behavioural changes observed in mental illness. In recent decades, rodent studies have significantly advanced our understanding of how early life stress (ELS) affects brain development and behaviour. These studies reveal that ELS has long-term consequences on the brain such as impairment of adult hippocampal neurogenesis, altering learning and memory. Despite such advances, several key questions remain inadequately answered, including a comprehensive overview of brain regions and molecular pathways that are altered by ELS and how ELS-induced molecular changes ultimately lead to behavioural changes in adulthood. The zebrafish represents a novel ELS model, with the potential to contribute to answering some of these questions. The zebrafish offers some important advantages such as the ability to non-invasively modulate stress hormone levels in a whole animal and to visualise whole brain activity in freely behaving animals. This review discusses the current status of the zebrafish ELS field and its potential as a new ELS model.

Reduced Firing of Nucleus Accumbens Parvalbumin Interneurons Impairs Risk Avoidance in DISC1 Transgenic Mice

A strong animal survival instinct is to approach objects and situations that are of benefit and to avoid risk. In humans, a large proportion of mental disorders are accompanied by impairments in risk avoidance. One of the most important genes involved in mental disorders is disrupted-in-schizophrenia-1 (DISC1), and animal models in which this gene has some level of dysfunction show emotion-related impairments. However, it is not known whether DISC1 mouse models have an impairment in avoiding potential risks. In the present study, we used DISC1-N terminal truncation (DISC1-N^TM) mice to investigate risk avoidance and found that these mice were impaired in risk avoidance on the elevated plus maze (EPM) and showed reduced social preference in a three-chamber social interaction test. Following EPM tests, c-Fos expression levels indicated that the nucleus accumbens (NAc) was associated with risk-avoidance behavior in DISC1-N^TM mice. In addition, in vivo electrophysiological recordings following tamoxifen administration showed that the firing rates of fast-spiking neurons (FS) in the NAc were significantly lower in DISC1-N^TM mice than in wild-type (WT) mice. In addition, in vitro patch clamp recording revealed that the frequency of action potentials stimulated by current injection was lower in parvalbumin (PV) neurons in the NAc of DISC1-N^TM mice than in WT controls. The impairment of risk avoidance in DISC1-N^TM mice was rescued using optogenetic tools that activated NAc^PV neurons. Finally, inhibition of the activity of NAc^PV neurons in PV-Cre mice mimicked the risk-avoidance impairment found in DISC1-N^TM mice during tests on the elevated zero maze. Taken together, our findings confirm an impairment in risk avoidance in DISC1-N^TM mice and suggest that reduced excitability of NAc^PV neurons is responsible.

Behavioral Effects of Developmental Exposure to JWH-018 in Wild-Type and Disrupted in Schizophrenia 1 (disc1) Mutant Zebrafish

Synthetic cannabinoids can cause acute adverse psychological effects, but the potential impact when exposure happens before birth is unknown. Use of synthetic cannabinoids during pregnancy may affect fetal brain development, and such effects could be moderated by the genetic makeup of an individual. Disrupted in schizophrenia 1 (DISC1) is a gene with important roles in neurodevelopment that has been associated with psychiatric disorders in pedigree analyses. Using zebrafish as a model, we investigated (1) the behavioral impact of developmental exposure to 3 μM 1-pentyl-3-(1-naphthoyl)-indole (JWH-018; a common psychoactive synthetic cannabinoid) and (2) whether disc1 moderates the effects of JWH-018. As altered anxiety responses are seen in several psychiatric disorders, we focused on zebrafish anxiety-like behavior. Zebrafish embryos were exposed to JWH-018 from one to six days post-fertilization. Anxiety-like behavior was assessed using forced light/dark and acoustic startle assays in larvae and novel tank diving in adults. Compared to controls, both acutely and developmentally exposed zebrafish larvae had impaired locomotion during the forced light/dark test, but anxiety levels and response to startle stimuli were unaltered. Adult zebrafish developmentally exposed to JWH-018 spent less time on the bottom of the tank, suggesting decreased anxiety. Loss-of-function in disc1 increased anxiety-like behavior in the tank diving assay but did not alter sensitivity to JWH-018. Results suggest developmental exposure to JWH-018 has a long-term behavioral impact in zebrafish, which is not moderated by disc1.

The implications of hypothalamic abnormalities for schizophrenia

Until a few years ago, the hypothalamus was believed to play only a marginal role in schizophrenia pathophysiology. However, recent findings show that this rather small brain region involved in many pathways found disrupted-in schizophrenia. Gross anatomic abnormalities (volume changes of the third ventricle, the hypothalamus, and its individual nuclei) as well as alterations at the cellular level (circumscribed loss of neurons) can be observed. Further, increased or decreased expression of hypothalamic peptides such as oxytocin, vasopressin, several factors involved in the regulation of appetite and satiety, endogenous opiates, products of schizophrenia susceptibility genes as well as of enzymes involved in neurotransmitter and neuropeptide metabolism have been reported in schizophrenia and/or animal models of the disease. Remarkably, although profound disturbances of the hypothalamus-pituitary-adrenal axis, hypothalamus-pituitary-thyroid axis, and the hypothalamus-pituitary-gonadal axis are typical signs of schizophrenia, there is currently no evidence for alterations in the expression of hypothalamic-releasing and inhibiting factors that control these hormonal axes. Finally, the implications of hypothalamus for disease-related disturbances of the sleep-wakefulness cycle and neuroimmune dysfunctions in schizophrenia are outlined.

Marijuana and Opioid Use during Pregnancy: Using Zebrafish to Gain Understanding of Congenital Anomalies Caused by Drug Exposure during Development

Marijuana and opioid addictions have increased alarmingly in recent decades, especially in the United States, posing threats to society. When the drug user is a pregnant mother, there is a serious risk to the developing baby. Congenital anomalies are associated with prenatal exposure to marijuana and opioids. Here, we summarize the current data on the prevalence of marijuana and opioid use among the people of the United States, particularly pregnant mothers. We also summarize the current zebrafish studies used to model and understand the effects of these drug exposures during development and to understand the behavioral changes after exposure. Zebrafish experiments recapitulate the drug effects seen in human addicts and the birth defects seen in human babies prenatally exposed to marijuana and opioids. Zebrafish show great potential as an easy and inexpensive model for screening compounds for their ability to mitigate the drug effects, which could lead to new therapeutics.

Premature birth stunts early growth and is a possible driver of stress-induced maternal effects in the guppy Poecilia reticulata

We tested the effects of gestational stress, principally in the form of alarm cue extracted from the skin of conspecifics, on reproduction in female guppies (Poecilia reticulata) and the growth and behaviour of their offspring. Offspring from mothers exposed to alarm cue exhibited stunted growth in the first few days post-partum, which appeared to be mediated by shortening of the gestation period, the length of which directly correlated with growth rate within the first 6 days post-partum. Mature offspring did not differ in behaviour or stress responses compared with controls and so the effects of maternal predation stress did not appear to persist into adulthood. A different form of gestational stress, dietary restriction, did not significantly affect offspring growth, though brood size was reduced, suggesting that the effects of predation stress were not mediated by differences in resource demand or consumption.

The zebrafish subcortical social brain as a model for studying social behavior disorders

Social behaviors are essential for the survival and reproduction of social species. Many, if not most, neuropsychiatric disorders in humans are either associated with underlying social deficits or are accompanied by social dysfunctions. Traditionally, rodent models have been used to model these behavioral impairments. However, rodent assays are often difficult to scale up and adapt to high-throughput formats, which severely limits their use for systems-level science. In recent years, an increasing number of studies have used zebrafish (Danio rerio) as a model system to study social behavior. These studies have demonstrated clear potential in overcoming some of the limitations of rodent models. In this Review, we explore the evolutionary conservation of a subcortical social brain between teleosts and mammals as the biological basis for using zebrafish to model human social behavior disorders, while summarizing relevant experimental tools and assays. We then discuss the recent advances gleaned from zebrafish social behavior assays, the applications of these assays to studying related disorders, and the opportunities and challenges that lie ahead.

A critical review of zebrafish schizophrenia models: Time for validation?

Schizophrenia is a mental disorder that affects 1% of the population worldwide and is manifested as a broad spectrum of symptoms, from hallucinations to memory impairment. It is believed that genetic and/or environmental factors may contribute to the occurrence of this disease. Recently, the zebrafish has emerged as a valuable and attractive model for various neurological disorders including schizophrenia. In this review, we describe current pharmacological models of schizophrenia with special emphasis on providing insights into the pros and cons of using zebrafish as a behavioural model of this disease. Moreover, we highlight the advantages and utility of using zebrafish for elucidating the genetic mechanisms underlying this psychiatric disorder. We believe that the zebrafish has high potential also in the area of precision medicine and may complement the development of therapeutics, especially for pharmacoresistant patients.

Sensory ecology of ostariophysan alarm substances

Chemical communication of predation risk has evolved multiple times in fish species, with conspecific alarm substance (CAS) being the most well understood mechanism. CAS is released after epithelial damage, usually when prey fish are captured by a predator and elicits neurobehavioural adjustments in conspecifics which increase the probability of avoiding predation. As such, CAS is a partial predator stimulus, eliciting risk assessment-like and avoidance behaviours and disrupting the predation sequence. The present paper reviews the distribution and putative composition of CAS in fish and presents a model for the neural processing of these structures by the olfactory and the brain aversive systems. Applications of CAS in the behavioural neurosciences and neuropharmacology are also presented, exploiting the potential of model fish [e.g., zebrafish Danio rerio, guppies Poecilia reticulata, minnows Phoxinus phoxinus) in neurobehavioural research.

The TRAX, DISC1, and GSK3 complex in mental disorders and therapeutic interventions

Psychiatric disorders (such as bipolar disorder, depression, and schizophrenia) affect the lives of millions of individuals worldwide. Despite the tremendous efforts devoted to various types of psychiatric studies and rapidly accumulating genetic information, the molecular mechanisms underlying psychiatric disorder development remain elusive. Among the genes that have been implicated in schizophrenia and other mental disorders, disrupted in schizophrenia 1 (DISC1) and glycogen synthase kinase 3 (GSK3) have been intensively investigated. DISC1 binds directly to GSK3 and modulates many cellular functions by negatively inhibiting GSK3 activity. The human DISC1 gene is located on chromosome 1 and is highly associated with schizophrenia and other mental disorders. A recent study demonstrated that a neighboring gene of DISC1, translin-associated factor X (TRAX), binds to the DISC1/GSK3β complex and at least partly mediates the actions of the DISC1/GSK3β complex. Previous studies also demonstrate that TRAX and most of its interacting proteins that have been identified so far are risk genes and/or markers of mental disorders. In the present review, we will focus on the emerging roles of TRAX and its interacting proteins (including DISC1 and GSK3β) in psychiatric disorders and the potential implications for developing therapeutic interventions.

Zebrafish Models of Neurodevelopmental Disorders: Past, Present, and Future

Zebrafish are increasingly being utilized as a model system to investigate the function of the growing list of risk genes associated with neurodevelopmental disorders. This is due in large part to the unique features of zebrafish that make them an optimal system for this purpose, including rapid, external development of transparent embryos, which enable the direct visualization of the developing nervous system during early stages, large progenies, which provide considerable tractability for performing high-throughput pharmacological screens to identify small molecule suppressors of simple behavioral phenotypes, and ease of genetic manipulation, which has been greatly facilitated by the advent of CRISPR/Cas9 gene editing technologies. This review article focuses on studies that have harnessed these advantages of the zebrafish system for the functional analysis of genes that are strongly associated with the following neurodevelopmental disorders: autism spectrum disorders (ASD), epilepsy, intellectual disability (ID) and schizophrenia. We focus primarily on studies describing early morphological and behavioral phenotypes during embryonic and larval stages resulting from loss of risk gene function. We highlight insights into basic mechanisms of risk gene function gained from these studies as well as limitations of studies to date. Finally, we discuss advances in in vivo neural circuit imaging in zebrafish, which promise to transform research using the zebrafish model by illuminating novel circuit-level mechanisms with relevance to neurodevelopmental disorders.

Proteostasis and Mitochondrial Role on Psychiatric and Neurodegenerative Disorders: Current Perspectives

Proteostasis involves processes that are fundamental for neural viability. Thus, protein misfolding and the formation of toxic aggregates at neural level, secondary to dysregulation of the conservative mechanisms of proteostasis, are associated with several neuropsychiatric conditions. It has been observed that impaired mitochondrial function due to a dysregulated proteostasis control system, that is, ubiquitin-proteasome system and chaperones, could also have effects on neurodegenerative disorders. We aimed to critically analyze the available findings regarding the neurobiological implications of proteostasis on the development of neurodegenerative and psychiatric diseases, considering the mitochondrial role. Proteostasis alterations in the prefrontal cortex implicate proteome instability and accumulation of misfolded proteins. Altered mitochondrial dynamics, especially in proteostasis processes, could impede the normal compensatory mechanisms against cell damage. Thereby, altered mitochondrial functions on regulatory modulation of dendritic development, neuroinflammation, and respiratory function may underlie the development of some psychiatric conditions, such as schizophrenia, being influenced by a genetic background. It is expected that with the increasing evidence about proteostasis in neuropsychiatric disorders, new therapeutic alternatives will emerge.