Functional reconstruction of the basal ganglia neural circuit by human striatal neurons in hypoxic-ischaemic injured brain

Sox2-overexpressing neural stem cells alleviate ventricular enlargement and neurological dysfunction in posthemorrhagic hydrocephalus

JOURNAL/nrgr/04.03/01300535-202602000-00045/figure1/v/2025-05-05T160104Z/r/image-tiff Neural stem cells (NSCs) have the potential for self-renewal and multidirectional differentiation, and their transplantation has achieved good efficacy in a variety of diseases. However, only 1%-10% of transplanted NSCs survive in the ischemic and hypoxic microenvironment of posthemorrhagic hydrocephalus. Sox2 is an important factor for NSCs to maintain proliferation. Therefore, Sox2-overexpressing NSCs (NSCSox2) may be more successful in improving neurological dysfunction after posthemorrhagic hydrocephalus. In this study, human NSCSox2 was transplanted into a posthemorrhagic hydrocephalus mouse model, and retinoic acid was administered to further promote NSC differentiation. The results showed that NSCSox2 attenuated the ventricular enlargement caused by posthemorrhagic hydrocephalus and improved neurological function. NSCSox2 also promoted nerve regeneration, inhibited neuroinflammation and promoted M2 polarization (anti-inflammatory phenotype), thereby reducing cerebrospinal fluid secretion in choroid plexus. These findings suggest that NSCSox2 rescued ventricular enlargement and neurological dysfunction induced by posthemorrhagic hydrocephalus through neural regeneration and modulation of inflammation.

Role of thyroid function in non-basal ganglia intracerebral hemorrhage prognosis

PURPOSE

Thyroid function disorders serve as unfavorable prognosis predictors for numerous diseases. However, their role in predicting intracerebral hemorrhage outcome is unclear. This study investigated the prognostic potential of thyroid function parameters for intracerebral hemorrhage.

METHODS

Admissions for intracerebral hemorrhage caused by hypertension were retrospectively enrolled to determine thyroid function levels. Patients were subjected to three month- and three year-follow up to assess short- and long-term prognosis, respectively.

RESULTS

Elevated levels of thyroxine and decreased levels of free triiodothyronine (fT3) are associated with unfavorable short-term prognosis in non-basal ganglia intracerebral hemorrhage patients. The levels of thyroid stimulating hormone and free tetraiodothyronine did not exhibit any significant change. This alteration in thyroid function was not observed in basal-ganglia intracerebral hemorrhage patients. Furthermore, the inclusion of thyroxine and fT3 enhanced the prognostic power of the traditional model (NIHSS only) in predicting short-term outcomes. Among patients 55 years or older, subgroup analyses results are consistent with previous findings. Additionally, our clinical model is also applicable towards predicting the long-term prognosis of non-basal ganglia intracerebral hemorrhage.

CONCLUSION

Thyroid function concentrations, especially the levels of thyroxine and fT3, could serve as key prognostic predictors for non-basal ganglia cerebral hemorrhage, especially among the middle-aged and elderly groups.

Circuit integration by transplanted human neurons

Transplantation-based cell therapy holds the potential to offer sustained and physiological repair for neurological diseases and injuries, which requires the integration of transplanted neurons into the neural circuits of the human brain. Recent studies involving transplantation of human pluripotent stem cell-derived neural progenitors into the brain of model animals reveal the remarkable capacity of grafted immature human neurons to mature, project axons in a long distance, and form both pre- and postsynaptic connections with host neurons, corresponding to functional recovery. Strikingly, this circuit integration depends largely on the identity of the transplanted cells and may be modified by external stimuli. This realization begs for enriched authentic target cells for transplantation and combination with rehabilitation for better therapeutic outcomes.

Copper supplementation alleviates hypoxia‑induced ferroptosis and oxidative stress in neuronal cells

Hypoxic ischemia is the primary cause of brain damage in newborns. Notably, copper supplementation has potential benefits in ischemic brain damage; however, the precise mechanisms underlying this protective effect remain unclear. In the present study, a hypoxic HT22 cell model was developed to examine the mechanism by which copper mitigates hypoxia‑induced oxidative stress. Cell viability was assessed using the Cell Counting Kit‑8 assay, mitochondrial structure was examined with a transmission electron microscope, intracellular ferrous ions and lipid reactive oxygen species levels in HT22 cells were measured using FerroOrange and BODIPY 581/591 C11 staining, copper content was determined using graphite furnace atomic absorption spectroscopy, and gene and protein expression were analyzed by reverse transcription‑quantitative PCR and western blotting. The present findings indicated that hypoxic exposure may lead to reduced cell viability, along with the upregulation of various markers associated with ferroptosis. Furthermore, hypoxia elevated the levels of reactive oxygen species, hydrogen peroxide and malondialdehyde, and decreased the activity of superoxide dismutase 1 (SOD1) in HT22 cells. In addition, the intracellular copper concentration exhibited a notable decrease, while supplementation with an appropriate dose of copper effectively shielded neurons from hypoxia‑induced oxidative stress and ferroptosis, and elevated cell viability in hypoxia‑exposed HT22 cells through the copper chaperone for superoxide dismutase/SOD1/glutathione peroxidase 4 axis. In conclusion, the present study identified a novel function of copper in protecting neurons from oxidative stress and ferroptosis under hypoxic conditions, providing fresh insights into the therapeutic potential of copper in mitigating hypoxia‑induced neuronal injury.

Transplanted deep-layer cortical neuroblasts integrate into host neural circuits and alleviate motor defects in hypoxic-ischemic encephalopathy injured mice

BACKGROUND

Hypoxic-ischemic encephalopathy (HIE) is a major cause of neonatal disability and mortality. Although intensive studies and therapeutic approaches, there are limited restorative treatments till now. Human embryonic stem cell (hESCs)-derived cortical neural progenitors have shown great potentials in ischemic stroke in adult brain. However, it is unclear whether they are feasible for cortical reconstruction in immature brain with hypoxic-ischemic encephalopathy.

METHODS

By using embryonic body (EB) neural differentiation method combined with DAPT pre-treatment and quantitative cell transplantation, human cortical neuroblasts were obtained and transplanted into the cortex of hypoxic-ischemic injured brain with different dosages 2 weeks after surgery. Then, immunostaining, whole-cell patch clamp recordings and behavioral testing were applied to explore the graft survival and proliferation, fate commitment of cortical neuroblasts in vitro, neural circuit reconstruction and the therapeutic effects of cortical neuroblasts in HIE brain.

RESULTS

Transplantation of human cortical neural progenitor cells (hCNPs) in HIE-injured cortex exhibited long-term graft overgrowth. DAPT pre-treatment successfully synchronized hCNPs from different developmental stages (day 17, day 21, day 28) to deep layer cortical neuroblasts which survived well in HIE injured brain and greatly prevented graft overgrowth after transplantation. Importantly, the cortical neuroblasts primarily differentiated into deep-layer cortical neurons and extended long axons to their projection targets, such as the cortex, striatum, thalamus, and internal capsule in both ipsilateral and contralateral HIE-injured brain. The transplanted cortical neurons established synapses with host cortical neurons and exhibited spontaneous excitatory or inhibitory post-synaptic currents (sEPSCs or sIPSCs) five months post-transplantation. Rotarod and open field tests showed greatly improved animal behavior by intra-cortex transplantation of deep layer cortical neuroblasts in HIE injured brain.

CONCLUSIONS

Transplanted hESCs derived cortical neuroblasts survive, project to endogenous targets, and integrate into host cortical neural circuits to rescue animal behavior in the HIE-injured brain without graft overgrowth, providing a novel and safe cell replacement strategy for the future treatment of HIE.

Construction of human 3D striato-nigral assembloids to recapitulate medium spiny neuronal projection defects in Huntington's disease

The striato-nigral (Str-SN) circuit is composed of medium spiny neuronal projections that are mainly sent from the striatum to the midbrain substantial nigra (SN), which is essential for regulating motor behaviors. Dysfunction of the Str-SN circuitry may cause a series of motor disabilities that are associated with neurodegenerative disorders, such as Huntington's disease (HD). Although the etiology of HD is known as abnormally expanded CAG repeats of the huntingtin gene, treatment of HD remains tremendously challenging. One possible reason is the lack of effective HD model that resembles Str-SN circuitry deficits for pharmacological studies. Here, we first differentiated striatum-like organoids from human pluripotent stem cells (hPSCs), containing functional medium spiny neurons (MSNs). We then generated 3D Str-SN assembloids by assembling striatum-like organoids with midbrain SN-like organoids. With AAV-hSYN-GFP-mediated viral tracing, extensive MSN projections from the striatum to the SN are established, which formed synaptic connection with GABAergic neurons in SN organoids and showed the optically evoked inhibitory postsynaptic currents and electronic field potentials by labeling the striatum-like organoids with optogenetic virus. Furthermore, these Str-SN assembloids exhibited enhanced calcium activity compared to that of individual striatal organoids. Importantly, we further demonstrated the reciprocal projection defects in HD iPSC-derived assembloids, which could be ameliorated by treatment of brain-derived neurotrophic factor. Taken together, these findings suggest that Str-SN assembloids could be used for identifying MSN projection defects and could be applied as potential drug test platforms for HD.

Bibliometric analysis of hot literature on neural circuit research

Numerous brain diseases have been attributed to abnormalities in the connections of neural circuits. Exploration of neural circuits may give enlightenment in treating some intractable brain diseases. Here, we screened all publications on neural circuits in the Web of Science database from 2007 to 2022 and analyzed the research trends through VOSviewer, CiteSpace, Microsoft Excel 2019, and Origin. The findings revealed a consistent upward trend in research on neural circuits during this period. The United States emerged as the leading contributor, followed by China and Japan. Among the top 10 institutions with the largest number of publications, both the United States and China have a strong presence. Notably, the Chinese Academy of Sciences demonstrated the highest publication output, closely followed by Stanford University. In terms of influential authors, Karl Deisseroth stood out as one of the most prominent investigators. During this period, the majority of publications and citations on neural circuit research were found in highly influential journals including NEURON, NATURE JOURNAL OF NEUROSCIENCE, and so forth. Keyword clustering analysis highlighted the increasing focus on neural circuits and photogenetics in neuroscience research, and the reconstruction of neural circuits has emerged as a crucial research direction in brain science. In conclusion, over the past 15 years, the increasing high-quality publications have facilitated research development of neural circuits, indicating a promising prospect for investigations on neurological and psychiatric diseases.