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Serum response factor (SRF) is a major transcription factor that regulates the expression of several plasticity-associated genes in the brain. Although the developmental expression of SRF in excitatory neurons is crucial for establishing proper hippocampal circuitry, no substantial evidence of its role in unstimulated mature neurons has been provided. The present study used time-controlled, conditional SRF knockout mice and found that the lack of SRF in adult neurons led to decreased actin levels and inactivation of the actin-severing protein cofilin 1 through its increase in phosphorylation at Ser3. The augmentation of cofilin 1 phosphorylation correlated with an alteration of dendritic spine morphology in the dentate gyrus, which was reflected by an increase in the number of spines that clustered into the long-spine category. The changes in spine morphology coincided with a lower amplitude and frequency of miniature excitatory postsynaptic currents. Moreover, SRF knockout animals were hyperactive and exhibited impairments in hippocampus-dependent behaviors, such as digging, marble burying, and nesting. Altogether, our data indicate that the adult deletion of neuronal SRF leads to alterations of spine morphology and function and hippocampus-dependent behaviors. Thus, SRF deletion in adult neurons recapitulates some aspects of morphological, electrophysiological, and behavioral changes that are observed in such psychiatric disorders as schizophrenia and autism spectrum disorders.

The megakaryoblastic leukaemia (MKL) family are serum response factor (SRF) coactivators, which are highly expressed in the brain. Accordingly, MKL plays important roles in dendritic morphology, neuronal migration, and brain development. Further, nucleotide substitutions in the MKL 1 and MKL 2 genes are found in patients with schizophrenia and autism spectrum disorder, respectively. Thus, studies on the precise synaptic localisation and function of MKL in neurons are warranted. In this study, we generated and tested new antibodies that specifically recognise endogenously expressed MKL1 and MKL2 proteins in neurons. Using these reagents, we biochemically and immunocytochemically show that MKL1 and MKL2 are localised at synapses. Furthermore, shRNA experiments revealed that postsynaptic deletion of MKL1 or MKL 2 reduced the percentage of mushroom- or stubby-type spines in cultured neurons. Taken together, our findings suggest that MKL1 and MKL2 are present at synapses and involved in dendritic spine maturation. This study may, at least in part, contribute to better understanding of the molecular mechanisms underlying MKL-mediated synaptic plasticity and neurological disorders.

Alterations in social behavior are core symptoms of major developmental neuropsychiatric diseases such as autism spectrum disorders or schizophrenia. Hence, understanding their molecular and cellular underpinnings constitutes the major research task. Dysregulation of the global gene expression program in the developing brain leads to modifications in a number of neuronal connections, synaptic strength and shape, causing unbalanced neuronal plasticity, which may be important substrate in the pathogenesis of neurodevelopmental disorders, contributing to their clinical outcome. Serum response factor (SRF) is a major transcription factor in the brain. The behavioral influence of SRF deletion during neuronal differentiation and maturation has never been studied because previous attempts to knock-out the gene caused premature death. Herein, we generated mice that lacked SRF from early postnatal development to precisely investigate the role of SRF starting in the specific time window before maturation of excitatory synapses that are located on dendritic spine occurs. We show that the time-controlled loss of SRF in neurons alters specific aspects of social behaviors in SRF knock-out mice, and causes deficits in developmental spine maturation at both the structural and functional levels, including downregulated expression of the AMPARs subunits GluA1 and GluA2, and increases the percentage of filopodial/immature dendritic spines. In aggregate, our study uncovers the consequences of postnatal SRF elimination for spine maturation and social interactions revealing novel mechanisms underlying developmental neuropsychiatric diseases.

Abstract Disturbances of gene expression patterns that occur during brain development can severely affect signal transmission, connectivity, and plasticity—key features that underlie memory formation and storage in neurons. Abnormalities at the molecular level can manifest as changes in the structural and functional plasticity of dendritic spines that harbor excitatory synapses. This can lead to such developmental neuropsychiatric conditions as Autism spectrum disorders, intellectual disabilities, and schizophrenia. The present study investigated the role of the major transcriptional regulator serum response factor (SRF) in synapse maturation and its impact on behavioral phenotypes. Using in vitro and in vivo models of early postnatal SRF deletion, we studied its influence on key morphological and physiological hallmarks of spine development. The elimination of SRF in developing neurons resulted in a phenotype of immature dendritic spines and impairments in excitatory transmission. Moreover, using a combination of molecular and imaging techniques, we showed that SRF-depleted neurons exhibited a lower level of specific glutamate receptor mRNAs and a decrease in their surface expression. Additionally, the early postnatal elimination of SRF in hippocampal CA1 excitatory neurons caused spine immaturity and a specific social deficit that is frequently observed in autism patients. Altogether, our data suggest that the regulation of structural and functional dendritic spine maturation begins at the stage of gene transcription, which underpins the crucial role of such transcription factors as SRF. Moreover, disturbances of the postnatal expression of SRF translate to behavioral changes in adult animals. Competing Interest Statement The authors have declared no competing interest.

Background The phosphorylation of the Light-Harvesting Complex of photosystem II (LHCII) driven by STATE TRANSITION 7 (STN7) kinase is a part of one of the crucial regulatory mechanisms of photosynthetic light reactions operating in fluctuating environmental conditions, light in particular. There are evidenced that STN7 can also be activated without light as well as in dark-chilling conditions. However, the biochemical mechanism standing behind this complex metabolic pathway has not been deciphered yet. Results In this work, we showed that dark-chilling induces light-independent LHCII phosphorylation in runner bean ( Phaseolus coccineus L.). In dark-chilling conditions, we registered an increased reduction of the PQ pool which led to activation of STN7 kinase, subsequent LHCII phosphorylation, and possible LHCII relocation inside the thylakoid membrane. We also presented the formation of a complex composed of phosphorylated LHCII and photosystem I typically formed upon light-induced phosphorylation. Moreover, we indicated that the observed steps were preceded by the activation of the oxidative pentose phosphate pathway (OPPP) enzymes and starch accumulation. Conclusions Our results suggest a direct connection between photosynthetic complexes reorganization and dark-chilling-induced activation of the thioredoxin system. The proposed possible pathway starts from the activation of OPPP enzymes and further NADPH-dependent thioredoxin reductase C (NTRC) activation. In the next steps, NTRC simultaneously activates ADP-glucose pyrophosphorylase and thylakoid membrane-located NAD(P)H dehydrogenase-like complex. These results in starch synthesis and electron transfer to the plastoquinone (PQ) pool, respectively. Reduced PQ pool activates STN7 kinase which phosphorylates LHCII. In this work, we present a new perspective on the mechanisms involving photosynthetic complexes while efficiently operating in the darkness. Although we describe the studied pathway in detail, taking into account also the time course of the following steps, the biological significance of this phenomenon remains puzzling.

Smart materials, especially light‐responsive, have become a key research area due to their tunable properties. It is related to the ability to undergo physical or chemical changes in response to external stimuli. Among them, photothermal responsive materials have attracted great interest. This study focuses on the development of a multilayer system (MS) consisting of benzophenone‐modified polydimethylsiloxane (PDMS) ring and a thermo‐responsive core made of poly(N‐isopropylacrylamide‐co‐N‐isopropylomethacrylamide) (P(NIPAAm‐co‐NIPMAAm)), gelatin, and gelatin methacrylate (GelMA). The system utilizes the thermal sensitivity of P(NIPAAm‐co‐NIPMAAm) and the photothermal effect of gold nanorods (AuNRs) to achieve an on‐demand controlled release mechanism within 6 min of near‐infrared (NIR) light irradiation. The mechanical properties investigated in the compression test show significant improvement in MS, reaching 60 times greater value than the material without a PDMS ring. In addition, NIR irradiation for 15 min activated the antimicrobial properties, eliminating 99.9% of E. Coli and 100% of S. Aureus, thus presenting pathogen eradication. This platform provides a versatile methodology for developing next‐generation smart materials, advanced delivery mechanisms, and multifunctional nanostructured composites. This work highlights the potential of photosensitive materials to revolutionize the field of soft robotics, optics and actuators, and on‐demand systems by providing precise control over release dynamics and improved material properties. This study presents a multilayer system (MS) based on benzophenone‐modified polydimethylsiloxane (PDMS) and a thermo‐responsive core incorporating P(NIPAAm‐co‐NIPMAAm), gelatin, and gelatin methacrylate (GelMA). The photothermal properties of gold nanorods, together with the thermal sensitivity of hydrogel, enable controlled detachment and release of hydrogel under near‐infrared (NIR) light irradiation, which activates bacterial eradication. MS shows a promising application for advanced smart materials and delivery systems.

This study investigates the synthesis, physicochemical characterization, and emulsifying performance of multifunctional polysiloxane modified with trimethoxysilane, eugenol and octane in varying molar ratios. The functionalized organosilicon compounds were synthesized by hydrosilylation and characterized using NMR, FT-IR, thermogravimetric analysis, and contact angle measurements. Their emulsifying properties were evaluated in oil-water emulsions, with stability assessed through centrifugation tests, multiple light scattering, and optical microscopy. The polysiloxane modified with trimethoxysilane: eugenol: octane with a 1:4:3 molar ratio exhibited the highest thermal stability. Emulsions formulated with this compound demonstrated superior physical stability, with backscattering destabilization rates as low as − 0.29%/day, attributed to enhanced interfacial interactions and hydrogen bonding. Emulsion containing polysiloxane modified only with eugenol and octane exhibited the lowest stability, with early phase separation observed after 1.5 h and backscattering rates reaching − 1.06%/day. These results highlight the critical role of silane functionalities in interfacial stabilization. These findings demonstrate the potential of structurally tailored polysiloxanes as advanced emulsifiers for applications in cosmetics, pharmaceuticals, and other industries.

Brain microvascular endothelial cells experience hypoxic conditions in several neurodegenerative disease processes and the underlying mechanisms still need to be explored. Current imaging modalities and biochemical assays require many specific markers that should be detected to identify the hypoxic response, especially at a level of single cells. This study presents a single-cell molecular imaging approach utilizing Fourier-Transform Infrared and Raman spectroscopy. Those methods enable the simultaneous detection of proteins, lipids, and nucleic acids encoded in their unique vibrational fingerprints. By establishing ratiometric estimators, we measured upregulated lipid metabolism, structural changes of proteins and asses DNA:RNA ratio at the single-cell level induced by oxygen depletion. Moreover, this approach allows for analyzing changes within specific cellular compartments, including nuclei, providing a comprehensive understanding of how hypoxia affects cellular functions and metabolism. Our findings pave the way for future investigations into the cellular adaptations to hypoxia in brain endothelial cells, potentially revealing novel therapeutic targets for neurodegenerative diseases.

Minipuberty is a transient phase of reproductive axis activation during the first several months of life, playing an important role in the development of reproductive organs in boys. Low 25-hydroxyvitamin D levels during pregnancy are associated with an increased risk of neonatal complications. An inadequate gestational vitamin D status is hypothesized to affect the postnatal activation of the hypothalamic–pituitary–gonadal axis. The purpose of our study was to assess whether a low vitamin D status during pregnancy determines the course of minipuberty in boys. The study included three groups of male infants born to women with different vitamin D statuses: sons of women with vitamin D deficiency (group 1), sons of women with vitamin D insufficiency (group 2), and male offspring of females with normal 25-hydroxyvitamin D levels (group 3 (the reference group)). Concentrations of testosterone, androstenedione, dehydroepiandrosterone sulfate, estradiol, progesterone, and 17-hydroxyprogesterone in saliva, as well as concentrations of gonadotropins in urine, were assayed monthly from postnatal months 1 to 6, and once every 2 months in the second half of the first year of life. Additionally, at each visit, penile length and testicular volume were assessed. Concentrations of testosterone, FSH, and LH, as well as penile length and testicular volume, were greater in group 1 than in groups 2 and 3. In turn, group 2 was characterized by higher FSH levels and a greater testicular volume than group 3. Peak concentrations of LH and testosterone were observed earlier in group 1 than in the remaining groups. The obtained results suggest that a low vitamin D status during pregnancy may have a stimulatory impact on reproductive axis activity and on the early postnatal development of male genital organs, correlating with the severity of hypovitaminosis D.

Reversible phosphorylation of photosystem II light harvesting complexes (LHCII) is a well-established protective mechanism enabling efficient response to changing light conditions. However, changes in LHCII phosphorylation were also observed in response to abiotic stress regardless of photoperiod. This study aimed to investigate the impact of dark-chilling on LHCII phosphorylation pattern in chilling-tolerant Arabidopsis thaliana and to check whether the disturbed LHCII phosphorylation process will impact the response of Arabidopsis to the dark-chilling conditions. We analyzed the pattern of LHCII phosphorylation, the organization of chlorophyll–protein complexes, and the level of chilling tolerance by combining biochemical and spectroscopy techniques under dark-chilling and dark conditions in Arabidopsis mutants with disrupted LHCII phosphorylation. Our results show that during dark-chilling, LHCII phosphorylation decreased in all examined plant lines and that no significant differences in dark-chilling response were registered in tested lines. Interestingly, after 24 h of darkness, a high increase in LHCII phosphorylation was observed, co-occurring with a significant FV/FM parameter decrease. The highest drop of FV/FM was detected in the stn7-1 line–mutant, where the LHCII is not phosphorylated, due to the lack of STN7 kinase. Our results imply that STN7 kinase activity is important for mitigating the adverse effects of prolonged darkness.