Feng-Shiun Shie

Background: These suggest that TML‐6’s ability to enter the brain parenchyma and possibly interact with and reduce Aβ, while possessing anti‐aging and anti‐inflammatory properties contributes to its effects on alleviating AD‐like pathology and behavioral deficit in APP/PS1 mice. Importantly, TML‐6 is safe and has promising drug bioavailability and exposure in pre‐clinical development. Taken together, TML‐6 exhibits promising druggability and meets the current strategy to develop as a first‐in‐class oral therapeutic drug for AD.Method: TML‐6 was applied to investigate the binding with Aβ peptide (1‐40 or 1‐42), hERG, and safety panel screening assay in vitro. Further, the effects of TML‐6 treatment on reducing AD‐like pathology, TML‐6 concentration in plasma‐to‐brain ratio, and inflammaging biomarkers in APP/PS1 mice were evaluated. Lastly, pharmacokinetic and toxicology studies in rats and dogs were performed.Result: Data from pre‐clinical development showed that TML‐6 bound Aβ_1‐40 and Aβ_1‐42 in vitro and improved behavioral deficits with reduced inflammaging in AD model mice (e.g., TNF‐α, IL‐1β, & IL‐6). The TML‐6 levels in the plasm and brain tended to dose‐dependently increase in AD mice, which inversely correlated with behavioral deficits and AD‐like pathologies. TML‐6 was well tolerated in toxicology in rats and dogs and had no off‐target safety pharmacology issue by hERG & safety panel screening. Most importantly, formulation optimization of TML‐6 exerted satisfactory drug bioavailability and exposure.Conclusion: These suggest that TML‐6’s ability to enter the brain parenchyma and possibly interact with and reduce Aβ, while possessing anti‐aging and anti‐inflammatory properties contributes to its effects on alleviating AD‐like pathology and behavioral deficit in APP/PS1 mice. Importantly, TML‐6 is safe and has promising drug bioavailability and exposure in pre‐clinical development. Taken together, TML‐6 exhibits promising druggability and meets the current strategy to develop as a first‐in‐class oral therapeutic drug for AD.

Alzheimer’s disease (AD) is a progressive neurodegenerative disease with a multifactorial etiology. A multitarget treatment that modulates multifaceted biological functions might be more effective than a single-target approach. Here, the therapeutic efficacy of combination treatment using anti-Aβ antibody NP106 and curcumin analog TML-6 versus monotherapy was investigated in an APP/PS1 mouse model of AD. Our data demonstrate that both combination treatment and monotherapy attenuated brain Aβ and improved the nesting behavioral deficit to varying degrees. Importantly, the combination treatment group had the lowest Aβ levels, and insoluble forms of Aβ were reduced most effectively. The nesting performance of APP/PS1 mice receiving combination treatment was better than that of other APP/PS1 groups. Further findings indicate that enhanced microglial Aβ phagocytosis and lower levels of proinflammatory cytokines were concurrent with the aforementioned effects of NP106 in combination with TML-6. Intriguingly, combination treatment also normalized the gut microbiota of APP/PS1 mice to levels resembling the wild-type control. Taken together, combination treatment outperformed NP106 or TML-6 monotherapy in ameliorating Aβ pathology and the nesting behavioral deficit in APP/PS1 mice. The superior effect might result from a more potent modulation of microglial function, cerebral inflammation, and the gut microbiota. This innovative treatment paradigm confers a new avenue to develop more efficacious AD treatments.

Increasing evidence suggests that elderly people with dementia are vulnerable to the development of severe coronavirus disease 2019 (COVID-19). In Alzheimer’s disease (AD), the major form of dementia, β-amyloid (Aβ) levels in the blood are increased; however, the impact of elevated Aβ levels on the progression of COVID-19 remains largely unknown. Here, our findings demonstrate that Aβ_1-42, but not Aβ_1-40, bound to various viral proteins with a preferentially high affinity for the spike protein S1 subunit (S1) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the viral receptor, angiotensin-converting enzyme 2 (ACE2). These bindings were mainly through the C-terminal residues of Aβ_1-42. Furthermore, Aβ_1-42 strengthened the binding of the S1 of SARS-CoV-2 to ACE2 and increased the viral entry and production of IL-6 in a SARS-CoV-2 pseudovirus infection model. Intriguingly, data from a surrogate mouse model with intravenous inoculation of Aβ_1-42 show that the clearance of Aβ_1-42 in the blood was dampened in the presence of the extracellular domain of the spike protein trimers of SARS-CoV-2, whose effects can be prevented by a novel anti-Aβ antibody. In conclusion, these findings suggest that the binding of Aβ_1-42 to the S1 of SARS-CoV-2 and ACE2 may have a negative impact on the course and severity of SARS-CoV-2 infection. Further investigations are warranted to elucidate the underlying mechanisms and examine whether reducing the level of Aβ_1-42 in the blood is beneficial to the fight against COVID-19 and AD.

Prenatal exposure to buprenorphine renders offspring vulnerable to cerebral impairments. In this study, our data demonstrate, for the first time, that prenatal exposure to buprenorphine escalates astrocyte activation concurrent with indications of endoplasmic reticulum (ER) stress in the hippocampi of neonates, and this can be prevented by the coadministration of dextromethorphan with buprenorphine. Furthermore, dextromethorphan can inhibit the accumulation of GPR37 in the hippocampus of newborns caused by buprenorphine and is accompanied by the proapoptotic ER stress response that involves the procaspase-3/CHOP pathway. Primary astrocyte cultures derived from the neonates of the buprenorphine group also displayed aberrant ER calcium mobilization and elevated basal levels of cyclooxygenase-2 (COX-2) at 14 days in vitro while showing sensitivity to lipopolysaccharide-activated expression of COX-2. Similarly, these long-lasting defects in the hippocampus and astrocytes were abolished by dextromethorphan. Our findings suggest that prenatal exposure to buprenorphine might instigate long-lasting effects on hippocampal and astrocytic functions. The beneficial effects of prenatal coadministration of dextromethorphan might be, at least in part, attributed to its properties in attenuating astrocyte activation and hippocampal ER stress in neonates.

Background: Chronic neuro‐inflammation leading to excessive neuronal damages predates the presence of clinical manifestations of Alzheimer’s disease (AD) by many years. Due to the complex pathogenesis of AD, a multi‐target regimen using a combination therapy is proposed to be essential to the effectiveness of AD therapy.Method: An innovative combination therapy using a newly developed multi‐functional Aβ antibody (NP106) and a novel curcumin derivative (TML‐6) was applied to treat APP/PS1 mice. To investigate whether synergistic effects of combination therapy on reducing AD‐like pathology in APP/PS1 mice alter fecal microbiome, high‐throughput 16S rRNA sequencing was performed.Result: Here, we demonstrate that monotherapy with either weekly intraperitoneal injection of low‐dose NP106 or TML‐6‐supplemented diet for four months showed beneficial effects on counteracting AD‐like pathology in APP/PS1 mice, while combination therapy using these two drugs outperformed monotherapy and exerted synergistic effects on improving behavioral abnormality and reducing cerebral Aβ accumulation. Data from microbiome indicate that the gut bacterial community structure of APP/PS1 mice was different from those of wt littermates. Intriguingly, relative abundant genera of APP/PS1 mice can be restored by either monotherapy or combination therapy to levels similar to wt littermates, indicating that these treatments possessed prebiotic effects against gut dysbiosis. Importantly, analyses of samples diversity further reveal that combination therapy might lead to better normalization of microbiota.Conclusion: Combination therapy exerted synergistic effects on attenuating AD‐like pathological features and behavioral deficits in APP/PS1 mice. Furthermore, the synergistic effects of combination therapy were concurrent with the normalization of gut microbiota.

The original version of this article unfortunately contained a mistake. The authors observed inadvertent error in Fig. 7d, in which the image of the GFAP/DAPI in the WT saline treated mice was rotated left 90-degree by mistake. The corrected representative image is given below.

Astrocyte activation is a common pathological feature in many brain diseases with neuroinflammation, and revealing the underlying mechanisms might shed light on the regulatory processes of the diseases. Recently, soluble epoxide hydrolase (sEH) has been proposed to affect neuroinflammation in brain injuries. However, the roles of astrocytic sEH in brains with neurodegeneration remain unclear. The expression of astrocytic sEH in the brains of APPswe/PSEN1dE9 (APP/PS1) mice developing Alzheimer’s disease (AD)-like pathology was evaluated by confocal imaging. LPS-activated primary astrocytes with mRNA silencing or overexpression of sEH were used to investigate its regulatory roles in astrocyte activation and the induction of pro-inflammatory markers. Primary astrocytes isolated from a sEH knockout (sEH−/−) background were also applied. The immunoreactivity of sEH was increased in activated astrocytes in parallel with the progression of AD in APP/PS1 mice. Our data from primary astrocyte cultures further demonstrate that the overexpression of sEH ameliorated, while the silencing of sEH mRNA enhanced, the lipopolysaccharides (LPS)-induced expression of pro-inflammatory markers, such as inducible nitric oxide, cyclooxygenase 2 (COX-2), and pro-inflammatory cytokines. These findings suggest that sEH negatively regulates astrocyte immune responses. Enhanced immune responses found in LPS-activated sEH−/− astrocytes also support the notion that the expression of sEH could suppress the immune responses during astrocyte activation. Similarly, sEH−/− mice that received intraperitoneal injection of LPS showed exacerbated astrocyte activation in the brain, as observed by the elevated expression of glial fibrillary acidic protein (GFAP) and pro-inflammatory markers. Moreover, our data show that the phosphorylation of the signal transducer and activator of transcription 3 (STAT3) was upregulated in activated astrocytes from sEH mouse brains, and the pharmacological blockade of STAT3 activity alleviated the pro-inflammatory effects of sEH deletion in LPS-activated primary astrocytes. Our results provide evidence, for the first time, showing that sEH negatively regulates astrocytic immune responses and GFAP expression, while the underlying mechanism at least partly involves the downregulation of STAT3 phosphorylation. The discovery of a novel function for sEH in the negative control of astrocytic immune responses involving STAT3 activation confers further insights into the regulatory machinery of astrocyte activation during the development of neurodegeneration.

Alzheimer’s disease (AD), a progressive neurodegenerative disease is highly associated with metabolic syndromes. We previously demonstrated that glycemic dysregulation and obesity are augmented in high fat diet (HFD)-treated APPswe/PS1dE9 (APP/PS1) transgenic mice. In the current study, the underlying mechanism mediating exacerbated metabolic stresses in HFD APP/PS1 transgenic mice was further examined. APP/PS1 mice developed insulin resistance and, consequently, impaired glucose homeostasis after 10 weeks on HFD. [¹⁸F]-2-fluoro-2-deoxy-d-glucose ([¹⁸F]-FDG) positron emission tomography showed that interscapular brown adipose tissue is vulnerable to HFD and AD-related pathology. Chronic HFD induced hyperphagia, with limited effects on basal metabolic rates in APP/PS1 transgenic mice. Excessive food intake may be caused by impairment of leptin signaling in the hypothalamus because leptin failed to suppress the food intake of HFD APP/PS1 transgenic mice. Leptin-induced pSTAT3 signaling in the arcuate nucleus was attenuated. Dysregulated energy homeostasis including hyperphagia and exacerbated obesity was elicited prior to the presence of the amyloid pathology in the hypothalamus of HFD APP/PS1 transgenic mice; nevertheless, cortical neuroinflammation and the level of serum Aβ and IL-6 were significantly elevated. Our study demonstrates the pivotal role of AD-related pathology in augmenting HFD-induced insulin and leptin resistance and impairing hypothalamic regulation of energy homeostasis.