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Advanced Neurology Role of immunosuppressants in autism

a role in synaptic pruning and the pathogenesis of ASD. birth . Caspase-3f/f C57BL/6 mice with the CASP3 allele
[67]
Specifically, caspases have been shown to be involved in floxed at exon 2 were used, and the results showed that
the elimination of weak or unnecessary synapses during the tyrosine hydroxylase (TH) profiles were drastically
brain development, and disruptions in this process have reduced in the TH-CASP3KO group No. of classes=51 .
[27]
been implicated in ASD [44,65] . Studies have identified a However, there were no appreciable variations in the total
number of genetic mutations and copy number variations number of synapses per area or the overall number of
associated with ASD that affect genes involved in synaptic synapses detected between the two groups, indicating that
function and plasticity, including those encoding proteins the dopaminergic pathways alone are solely responsible
involved in caspase-mediated synaptic pruning. For for the decrease in synaptic density in the TH-CASP3KO
example, mutations in the SHANK3 gene, which encodes group. This led the author to the conclusion that CASP3
a protein that interacts with caspases and is involved in plays a crucial role in the formation and maturation of
the regulation of synaptic pruning, have been linked to synapses in the mesencephalic dopaminergic system, and
ASD . Apoptosis and axonal fine-tuning processes are the loss of this protein in this region may serve as a useful
[66]
directly mediated by pathways that contain cysteine- animal model of ASD .
[27]
aspartate proteases known as caspases. Proteolytic cleavage
is a closely regulated mechanism that converts inactive In addition, the nigrostriatal dopaminergic pathway is
zymogens (caspases produced in healthy cells) into active negatively impacted by the selective elimination of Casp3
caspases. These caspases can be further classified as either in catecholaminergic neurons. It exhibits a full range of
[27]
initiator or ECs). ECs (caspases-3, -6, and -7) undergo classic ASD characteristics . The best-known activator
direct proteolytic activation at the hands of initiator caspase, caspase-8 (CASP8), may have a role in both
caspases (caspases-2, -8, -9, and 10) . In response to pro- ASD and the development of the dopaminergic system
[20]
apoptotic stimuli, this EC family degrades proteins and through the extrinsic pathway. According to the findings
cellular structures as part of the apoptotic process, also of the research, the deletion of CASP8 in the dopaminergic
known as “programmed cell death.” Neural circuits are built system was discovered to be implicated in the changes
during developmental phase of baby in which new neurons in the nigrostriatal pathway, which led to an increase in
are created and connect to pre-existing neurons and brain the number of TH-positive neurons in substantia nigra
structures. During this process, unnecessary connections pars compacta (SNPC). Studies in TH-CASP8KO mice,
are created, and it is necessary to delete these unnecessary involving neurochemical and anatomical research, showed
connections to verify that the neuronal circuitry is effective that systemic dopaminergic hypofunction causes behaviors
and functional [21,22] . Pruning is the term for this method that are partially comparable with ASD. This reveals the
and hence involved in developmental stage of baby and any role of caspases in dopaminergic system development
type of defect in this stage can lead to neurodevelopmental and wiring, providing insight into the pathophysiology of
[68]
disorder which can further leads to autism. ASD . El-Ansary et al. study found that all 20 Saudi autistic
patients had significantly higher levels of transforming
ECs coordinate pruning activities in response to growth factor and caspase-7, measuring above 80 pg/mL
pro-apoptotic stimuli, and defects in these caspases and 7.5 ng/mL, respectively, which were the highest levels
have been linked to developmental disorders such as observed compared to the control subjects . This finding
[69]
autism and schizophrenia . It is thought that apoptotic was based on the fact that these concentrations were the
[23]
caspases (ECs 3, 6, 7) play critical roles in the elimination highest shown in autistic patients. The study indicates that
of increased and non-functional synapses, as well as the significant increase in caspase-7 levels could be linked
the expulsion of extra cells, during the early stages of to a decreased nuclear factor kappa B (NF-κB) signaling-
development, and that dysfunction of such a system mediated survival activity, which was previously associated
may thus contribute to the basis of a wide range of with heat shock protein 70 through a different mechanism.
neurological and psychiatric disorders . In this work, the
[27]
author establishes CASP3’s significance for the midbrain Increased caspase-7 activity contributes to brain
dopaminergic system’s development and subsequent apoptosis and pro-inflammatory processes, as well as to the
hypofunction. CASP3 is an EC that is most well-known for etiopathogenesis of autism, which was previously revealed
its action in apoptosis; nevertheless, there has been a rising in the recent work , in which caspase-3, a proapoptotic
[70]
recognition of novel non-apoptotic functions described biomarker, had a substantial drop in the plasma, indicating
for this caspase in the brain. These functions have been that it had a considerable elevation in the brains of Saudi
linked to CASP3 in the brain . Casp3-knockout mice autistic patients when compared to controls of the same
[67]
have hyperplasia and abnormal brain cell migration, and age and gender . Upregulation of the protein E6AP,
[69]
depending on the mouse strain, they may die soon after which is directly associated with ASD, is caused by a rise

Volume 2 Issue 2 (2023) 7 https://doi.org/10.36922/an.391