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Aims: African Americans (AA) in the United States have a high risk of type 2 diabetes mellitus (T2DM) and suffer from disparities in the prevalence, mortality, and comorbidities of the disease compared to other Americans. The present study aimed to shed light on the molecular mechanisms of disease pathogenesis of T2DM among AA in the Washington, DC region. Methods: We performed TaqMan Low Density Arrays (TLDA) on 24 genes of interest that belong to three categories: metabolic disease and disorders, cancer‐related genes, and neurobehavioural disorders genes. The 18 genes, viz. ARNT, CYP2D6, IL6, INSR, RRAD, SLC2A2 (metabolic disease and disorders), APC, BCL2, CSNK1D, MYC, SOD2, TP53 (Cancer‐related), APBA1, APBB2, APOC1, APOE, GSK3B, and NAE1 (neurobehavioural disorders), were differentially expressed in T2DM participants compared to controls. Results: Our results suggest that factors including gender, smoking habits, and the severity or lack of control of T2DM (as indicated by HbA1c levels) were significantly associated with differential gene expression. APBA1 was significantly (p‐value <0.05) downregulated in all diabetes participants. Upregulation of APOE and CYP2D6 genes and downregulation of the INSR gene were observed in the majority of diabetes patients. Conclusions: Tobacco smoking and gender were significantly associated with case‐control differences in expression of the APBA1 and APOE genes (connected with Alzheimer's disease) and the INSR and CYP2D6 (associated with metabolic disorders). The results highlight the need for more effective management of T2DM and for tobacco smoking cessation interventions in this community, and further research on the associations of T2DM with other disease processes, including cancer and neurobehavioral pathways. [ABSTRACT FROM AUTHOR]

Background: Alzheimer's disease (AD) is the leading cause of dementia worldwide. Developing countries will have >3 times the prevalence of the developed countries by the year 2050. Our previous studies with a Pakistani population have suggested that type 2 diabetes mellitus (T2DM) is strongly associated with impaired cognitive functioning, and genetic pathways showed strong resemblance to known AD patterns. The present case studies investigated two important pathways, i.e., Amyloid Precursor Protein (APP) processing and Lipid Metabolism, using gene expression profiling arrays to compare and contrast AD and T2DM patients from Pakistan. Method: We performed high‐throughput qRT‐PCR with preconfigured a TaqMan Low Density Profiling Array specific to Human Alzheimer's Disease (ABI, CAT # 441887) to measure the altered gene expressions and their corresponding pathways (Ingenuity Pathway Analysis, IPA®). Both the T2DM (n = 2; M/F each) and AD (n = 2, M/F each) patients (cases) were recruited from outpatient departments of a regional hospital, and were compared with their respective matched, healthy controls. Result: Overall, we observed a differential gene expression profile in AD and T2DM participants compared to controls. CYP46A1, MAPT, CAPNS1, GAL, AGER, CAPN1, PSENEN, ST6GAL1, GRIN2B, GRIN2C, GRIN2A, and GAP43 was downregulated in both T2DM and AD patients. ACHE, CHRM3, GRIN2C and GAP43 significantly (p value <0.05) downregulated in all T2DM patients. CDC2, UCHL1, CTSG, CASP3, IDE, NAE1, CDK5R1, IL6, APBB2, GLS are the top 10 common genes that were upregulated in both AD and T2DM groups. The IPA analysis revealed important Canonical Pathways, that included, viz., Amyloid Processing, Neuroinflammation Signaling, ErB4 Signaling, nNOs Signaling. Molecular Mechanisms of Cancer. The top disease and biofunctions included Metabolic Disease, Neurological disease, Organismal Injury and Abnormalities, Psychological Disorders, Cardiovascular Disease, with the top upstream regulators PHLPP2, IL33, APP, CRP, TAC1. Conclusion: The differential gene expression patterns and associated disease pathways from this pilot study suggest that specific genes and pathways were common to both diseases and may suggest common underlying processes and causes. Information from such biochemical and genetic studies will be crucial to the development of therapeutic targets to treat AD. [ABSTRACT FROM AUTHOR]