MicroRNAs as potential biomarkers for diagnosis of schizophrenia and influence of antipsychotic treatment

Chara cterized by positive symptoms(such as changes in behavior or thoughts,including delusions and hallu cinations),negative symptoms(such as apathy,anhedonia,and social withdrawal),and cognitive impairments,schizophrenia is a chro nic,severe,and disabling mental disorder with late adolescence or early adulthood onset,Antipsychotics are the most commonly used drugs to treat schizophrenia,but those currently in use do not fully reverse all three types of symptoms characte rizing this condition.Schizophrenia is frequently misdiagnosed,resulting in a delay of or inappropriate treatment.Abnormal expression of microRNAs is connected to brain development and disease and could provide novel biomarkers for the diagnosis and prognosis of schizophrenia.The recent studies reviewed included microRNA profiling in blood-and urine-based materials and nervous tissue mate rials.From the studies that had validated the preliminary findings,potential candidate biomarkers for schizophrenia in adults could be miR-22-3p,-30e-5p,-92a-3p,-148b-5p,-181a-3p,-181a-5p,-181b-5p,-199 b-5p,-137 in whole blood,and miR-130b,-193a-3p in blood plasma.Antipsychotic treatment of schizophrenia patients was found to modulate the expression of certain microRNAs including miR-130b,-193a-3p,-132,-195,-30e,-432 in blood plasma.Further studies are warranted with adolescents and young adults having schizophrenia and consideration should be given to using animal models of the disorder to investigate the effect of suppressing or overexpressing specific microRNAs.

MicroRNAs as potential diagnostic biomarkers for bipolar disorder

Abnormal expression of microRNAs is connected to brain development and disease and could provide novel biomarkers for the diagnosis and prognosis of bipolar disorder. We performed a PubMed search for microRNA biomarkers in bipolar disorder and found 18 original research articles on studies performed with human patients and published from January 2011 to June 2023. These studies included microRNA profiling in bloodand brain-based materials. From the studies that had validated the preliminary findings,potential candidate biomarkers for bipolar disorder in adults could be miR-140-3p,-30d-5p,-330-5p,-378a-5p,-21-3p,-330-3p,-345-5p in whole blood, miR-19b-3p,-1180-3p,-125a-5p, let-7e-5p in blood plasma, and miR-7-5p,-23b-5p,-142-3p,-221-5p,-370-3p in the blood serum. Two of the studies had investigated the changes in microRNA expression of patients with bipolar disorder receiving treatment. One showed a significant increase in plasma miR-134 compared to baseline after 4 weeks of treatment which included typical antipsychotics, atypical antipsychotics, and benzodiazepines. The other study had assessed the effects of prescribed medications which included neurotransmitter receptorsite binders(drug class B) and sedatives, hypnotics, anticonvulsants, and analgesics(drug class C) on microRNA results. The combined effects of the two drug classes increased the significance of the results for miR-219 and-29c with miR-30e-3p and-526b* acquiring significance. MicroRNAs were tested to see if they could serve as biomarkers of bipolar disorder at different clinical states of mania, depression, and euthymia. One study showed that upregulation in whole blood of miR-9-5p,-29a-3p,-106a-5p,-106b-5p,-107,-125a-3p,-125b-5p and of miR-107,-125a-3p occurred in manic and euthymic patients compared to controls, respectively, and that upregulation of miR-106a-5p,-107 was found for manic compared to euthymic patients. In two other studies using blood plasma,downregulation of miR-134 was observed in manic patients compared to controls, and dysregulation of miR-134,-152,-607,-633,-652,-155 occurred in euthymic patients compared to controls. Finally, microRNAs such as miR-34a,-34b,-34c,-137, and-140-3p,-21-3p,-30d-5p,-330-5p,-378a-5p,-134,-19b-3p were shown to have diagnostic potential in distinguishing bipolar disorder patients from schizophrenia or major depressive disorder patients, respectively. Further studies are warranted with adolescents and young adults having bipolar disorder and consideration should be given to using animal models of the disorder to investigate the effects of suppressing or overexpressing specific microRNAs.