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Background: In pre-clinical studies, Bryostatin, MW (molecular weight) 904, has demonstrated synaptogenic, anti-apoptotic, anti-amyloid, and anti-tau tangle efficacies. Objective: To identify AD patients who show significant cognitive benefit versus placebo when treated in a trial with chronic Bryostatin dosing. Methods: In this 6-month 122 AD patient Bryostatin trial, there were two cohorts: the Moderate Cohort (MMSE, Mini-Mental Status Exam: 15-18) and the Moderately Severe Cohort (MMSE 10-14) as pre-specified secondary endpoints. Patient randomization was stratified by baseline SIB to insure balance in baseline cognitive ability between treatment arms. Results: With no safety events noted by the data safety and monitoring board, the Moderately Severe (MMSE 10-14) Bryostatin-treated patients were significantly improved above the placebo patients for Weeks #13 through Week #42. After two cycles of 7 x i.v. Bryostatin doses over a 26-week period, the 10-14 Cohort Severe Impairment Battery (SIB), measured every 2 weeks, showed significant benefit using a Mixed Model Repeated Measures model (MMRM, 2-tailed, p < 0.05) for Weeks #13 through #42, even 16 weeks after dosing completion by Week #26. Placebo 10-14 patients showed no benefit, declining to negative 12.8 points by Week #42. Trend analyses confirmed the MMRM data for this Cohort, with a significant downward slope (equivalent to Cognitive Decline) for the placebo group, p < 0.001, 2-tailed, but no significant decline for the Bryostatin-treated group (p = 0.409, NS), treatment versus placebo p < 0.007. The Moderate Cohort patients showed no significant benefit. Conclusions: The Bryostatin-treated MMSE 10-14 patients showed no significant cognitive decline throughout the 10-month trial, versus placebo patients' decline of -12.8 SIB points. [ABSTRACT FROM AUTHOR]

Protein kinase C delta (PKC-δ) is an important signaling molecule in human cells that has both proapoptotic as well as antiapoptotic functions. These conflicting activities can be modulated by two classes of ligands, phorbol esters and bryostatins. Phorbol esters are known tumor promoters, while bryostatins have anti-cancer properties. This is despite both ligands binding to the C1b domain of PKC-δ (δC1b) with a similar affinity. The molecular mechanism behind this discrepancy in cellular effects remains unknown. Here, we have used molecular dynamics simulations to investigate the structure and intermolecular interactions of these ligands bound to δC1b with heterogeneous membranes. We observed clear interactions between the δC1b-phorbol complex and membrane cholesterol, primarily through the backbone amide of L250 and through the K256 side-chain amine. In contrast, the δC1b-bryostatin complex did not exhibit interactions with cholesterol. Topological maps of the membrane insertion depth of the δC1b-ligand complexes suggest that insertion depth can modulate δC1b interactions with cholesterol. The lack of cholesterol interactions suggests that bryostatin-bound δC1b may not readily translocate to cholesterol-rich domains within the plasma membrane, which could significantly alter the substrate specificity of PKC-δ compared to δC1b-phorbol complexes. [ABSTRACT FROM AUTHOR]

Background: In pre-clinical studies of Alzheimer's disease (AD) transgenic mice, bryostatin restored synaptic connections, prevented neuronal death, reduced amyloid plaques, and reduced neurofibrillary tangles.Objective: Within pre-specified cohorts of advanced AD patients in two double-blind placebo-controlled bryostatin Phase II trials, to conduct exploratory statistical analyses of patients with identical conditions of enrollment and treatment.Methods: Severe Impairment Battery (SIB) scores above baseline at 5, 9, and 13 weeks were analyzed initially in the complete cases, with multiple imputation methods based on an iterative Markov chain Monte Carlo algorithm used for missing SIB scores. To mitigate confounding by a chance imbalance of 4.9 SIB baseline scores (Study #203), each patient was used as their own control with differences in 13-week SIB from baseline in single trial and pooled analyses to measure benefit at 13 weeks using general estimating equations (GEE) modeling.Results: Patients treated with bryostatin pre-specified at Mini-Mental State Examination scores 10-14, without memantine, showed baseline balance, complete safety, and SIB improvements at 13 weeks with multiple imputation analysis: Study #203 = 4.1 SIB points above baseline (p = 0.005), and Study #202 = 4.2 SIB points above baseline (p = 0.016). An increased power (N = 95) "pooled analysis" showed an increased SIB over time and a higher mean SIB at 13 weeks in the bryostatin treatment group (p < 0.001) but not significant (NS) for the placebo patients.Conclusion: Pre-specified exploratory analyses for the individual trials and the pooled trials confirmed significant bryostatin-induced improvement over baseline (treatment p < 0.001, placebo NS). [ABSTRACT FROM AUTHOR]

AIDS is a pandemic disease caused by HIV that affects 37 million people worldwide. Current antiretroviral therapy slows disease progression but does not eliminate latently infected cells, which resupply active virus, thus necessitating lifelong treatment with associated compliance, cost, and chemoexposure issues. Latencyreversing agents (LRAs) activate these cells, allowing for their potential clearance, thus presenting a strategy to eradicate the infection. Protein kinase C (PKC) modulators—including prostratin, ingenol esters, bryostatin, and their analogs—are potent LRAs in various stages of development for several clinical indications. While LRAs are promising, a major challenge associated with their clinical use is sustaining therapeutically meaningful levels of the active agent while minimizing side effects. Here we describe a strategy to address this problem based on LRA prodrugs, designed for controllable release of the active LRA after a single injection. As intended, these prodrugs exhibit comparable or superior in vitro activity relative to the parent compounds. Selected compounds induced higher in vivo expression of CD69, an activation biomarker, and, by releasing free agent over time, significantly improved tolerability when compared to the parent LRAs. More generally, selected prodrugs of PKC modulators avoid the bolus toxicities of the parent drug and exhibit greater efficacy and expanded tolerability, thereby addressing a longstanding objective for many clinical applications. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effect of bryostatin on the proliferation of ependymoma cells, and the underlying mechanism(s). Methods: Ependymoma cell lines (SC-EPN1 and SC-EPN2) were cultured in Dulbecco's modified Eagle's medium (DMEM) supplemented with 10 % fetal bovine serum (FBS) and streptomycin (10 mg/ml) in a humidified incubator at 37 °C and 5 % CO2 atmosphere. Rhe cells were randomly assigned to six groups: control group and five bryostatin groups treated with increasing concentrations of bryostatin (10 - 50 µM). Cell proliferation was determined by MTT assay, while real-time quantitative polymerase chain reaction (qRT-PCR) was used to determine the levels of expressions of apoptosisrelated genes. Expressions of cyclooxygenase-2 (COX-2), interleukin-8 (IL-8), Bcl-2, Bax and Pglycoprotein were determined using Western blotting. Results: Treatment with bryostatin significantly and concentration-dependently down-regulated COX-2 and IL-8 mRNAs expressions (p < 0.05). On the other hand, proliferation of SC-EPN1 and SC-EPN2 cells were significantly and concentration-dependently inhibited by bryostatin, relative to control group (p < 0.05). After 72 h of treatment with bryostatin (50 µM), the extent of apoptosis was significantly higher in SC-EPN1 (57.43 %) and SC-EPN2 cells (52.29 %) than in control group (2.37 %, p < 0.05). The results of Western blotting showed that treatment with bryostatin significantly reduced the expressions of Bcl-2 in ependymoma cells, relative to the control group (p < 0.05). However, there were no significant differences in the expression of Bax among the groups (p > 0.05). P-glycoprotein expression was significantly higher in bryostatin groups than in control group (p < 0.05). The results of flow cytometric analysis of rhodamine-123 (rh123) fluorescence showed that after 72 h of treatment with bryostatin (50 µM), rhl23 fluorescence significantly decreased in SC-EPN1 (8.10 %) and SC-EPN2 cells (10.11 %), relative to control group (20.83 %, p < 0.05). Conclusion: Bryostatin exerts anti-proliferative and apoptotic effects on ependymoma cells by suppressing COX-2 and IL-8 expressions. Thus, the inhibition of COX-2 expression may constitute an effective chemotherapeutic strategy for ependymoma treatment. [ABSTRACT FROM AUTHOR]

Disease ailments are changing the patterns, and the new diseases are emerging due to changing environments. The enormous growth of world population has overburdened the existing resources for the drugs. And hence, the drug manufacturers are always on the lookout for new resources to develop effective and safe drugs for the increasing demands of the world population. Seventy-five percentage of earth's surface is covered by water but research into the pharmacology of marine organisms is limited, and most of it still remains unexplored. Marine environment represents countless and diverse resource for new drugs to combat major diseases such as cancer or malaria. It also offers an ecological resource comprising a variety of aquatic plants and animals. These aquatic organisms are screened for antibacterial, immunomodulator, anti-fungal, anti-inflammatory, anticancer, antimicrobial, neuroprotective, analgesic, and antimalarial properties. They are used for new drug developments extensively across the world. Marine pharmacology offers the scope for research on these drugs of marine origin. Few institutes in India offer such opportunities which can help us in the quest for new drugs. This is an extensive review of the drugs developed and the potential new drug candidates from marine origin along with the opportunities for research on marine derived products. It also gives the information about the institutes in India which offer marine pharmacology related courses.

Bryozoans, commonly known as “moss animals”, are typically aquatic, filter feeding, sessile, colonial marine animals. Although, they are a rich resource of new bioactive secondary metabolites, but studies on their secondary metabolite have been neglected. Although over 8000 species are known, the lowest numbers of novel compounds were isolated from the phylum Bryozoa. In addition, presently nothing is recognized regarding the origin of the bioactive compounds isolated by bryozoans. At present nothing is known regarding the origin of the natural products isolated by bryozoans. The most famous of compounds obtained from these organisms are macrolide lactones of Bryostatins. They are potent modulators of protein kinase C. The amazing compounds such as Flustramines, Hinckdentine, Convolutamines, Kororamides, Chatellines, Chartellamides, Convolutamines, Convolutamidines, euthyroideone, amathaspiramide, lutamides, Volutamides, tambjamines, Phidolopins, and dozens of other compounds with different biological properties have been obtained. Very few studies have been done on these treasures in the sea depth, and more studies need to be done on them for access to their secondary metabolites.

Background: Bryostatin-activated PKC epsilon pre-clinically induces synaptogenesis, anti-apoptosis, anti-amyloid-β oligomers, and anti-hyperphosphorylated tau.Objectives: To investigate bryostatin safety, tolerability, and efficacy to improve cognition in advanced Alzheimer's disease (AD) patients.Methods: A double-blind, randomized, placebo-controlled Phase II, 12-week trial of i.v. bryostatin for 150 advanced AD patients (55-85) with MMSE-2 of 4-15, randomized 1:1:1 into 20 μg and 40 μg bryostatin, and placebo arms. The Full Analysis Set (FAS) and the Completer Analysis Set (CAS) were pre-specified alternative assessments (1-sided, p < 0.1 for primary efficacy, and 2-sided, p < 0.05 for pre-specified and post hoc exploratory analyses).Results: The safety profile was similar for 20 μg treatment and placebo patients. The 40 μg patients showed safety and drop-out issues, but no efficacy. Primary improvement of Severe Impairment Battery (SIB) scores at 13 weeks was not significant (p = 0.134) in the FAS, although in the CAS, the SIB comparison favored 20 μg bryostatin compared to placebo patients (p < 0.07). Secondary analyses at weeks 5 and 15 (i.e., 30 days post-final dosing) also favored 20 μg bryostatin compared to placebo patients. A pre-specified ANCOVA for baseline memantine blocking bryostatin and positive post-hoc trend analyses were statistically significant (2-sided, p < 0.05).Conclusion: Although the primary endpoint was not significant in the FAS, primary and secondary analyses in the CAS, and pre-specified and post-hoc exploratory analyses did favor bryostatin 20 μg compared to the placebo cohort. These promising Phase II results support further trials of 20 μg bryostatin- without memantine- to treat AD. [ABSTRACT FROM AUTHOR]

HIV latency in resting CD4+ T cell represents a key barrier preventing cure of the infection with antiretroviral drugs alone. Latency reversing agents (LRAs) can activate HIV expression in latently infected cells, potentially leading to their elimination through virus-mediated cytopathic effects, host immune responses, and/or therapeutic strategies targeting cells actively expressing virus. We have recently described several structurally simplified analogs of the PKC modulator LRA bryostatin (termed bryologs) designed to improve synthetic accessibility, tolerability in vivo, and efficacy in inducing HIV latency reversal. Here we report the comparative performance of lead bryologs, including their effects in reducing cell surface expression of HIV entry receptors, inducing proinflammatory cytokines, inhibiting short-term HIV replication, and synergizing with histone deacetylase inhibitors to reverse HIV latency. These data provide unique insights into structure-function relationships between A- and B-ring bryolog modifications and activities in primary cells, and suggest that bryologs represent promising leads for preclinical advancement. [ABSTRACT FROM AUTHOR]

Multiple sclerosis (MS) is an inflammatory disorder targeting the central nervous system (CNS). The relapsing-remitting phase of MS is largely driven by peripheral activation of autoreactive T-helper (Th) 1 and Th17 lymphocytes. In contrast, compartmentalized inflammation within the CNS, including diffuse activation of innate myeloid cells, characterizes the progressive phase of MS, the most debilitating phase that currently lacks satisfactory treatments. Recently, bryostatin-1 (bryo-1), a naturally occurring, CNS-permeable compound with a favorable safety profile in humans, has been shown to act on antigen-presenting cells to promote differentiation of lymphocytes into Th2 cells, an action that might benefit Th1-driven inflammatory conditions such as MS. In the present study, we show that bryo-1 provides marked benefit in mice with experimental autoimmune encephalomyelitis (EAE), an experimental MS animal model. Preventive treatment with bryo-1 abolishes the onset of neurologic deficits in EAE.More strikingly, bryo-1 reverses neurologic deficits after EAE onset, even when treatment is initiated at a late stage of disease when peak adaptive immunity has subsided. Treatment with bryo-1 in vitro promotes an anti-inflammatory phenotype in antigen-presenting dendritic cells, macrophages, and to a lesser extent, lymphocytes. These findings suggest the potential for bryo-1 as a therapeutic agent in MS, particularly given its established clinical safety. Furthermore, the benefit of bryo-1, even in late treatment of EAE, combined with its targeting of innate myeloid cells suggests therapeutic potential in progressive forms of MS. [ABSTRACT FROM AUTHOR]

Human immunodeficiency virus type 1 (HIV-1) establishes transcriptionally silent latent infections in resting memory T cells and hematopoietic stem and progenitor cells (HSPCs), which allows the virus to persist in infected individuals despite antiretroviral therapy. Developing in vitro models of HIV-1 latency that recapitulate the characteristics of latently infected cells in vivo is crucial to identifying and developing effective latency-reversing therapies. HSPCs exist in a quiescent state in vivo, and quiescence is correlated with latent infections in T cells. However, current models for culturing HSPCs and for infecting T cells in vitro require that the cells be maintained in an actively proliferating state. Here we describe a novel culture system in which primary human HSPCs cultured under hypothermic conditions are maintained in a quiescent state. We show that these quiescent HSPCs are susceptible to predominantly latent infection with HIV-1, while actively proliferating and differentiating HSPCs obtain predominantly active infections. Furthermore, we demonstrate that the most primitive quiescent HSPCs are more resistant to spontaneous reactivation from latency than more differentiated HSPCs and that quiescent HSPCs are resistant to reactivation by histone deacetylase inhibitors or P-TEFb activation but are susceptible to reactivation by protein kinase C (PKC) agonists. We also demonstrate that inhibition of HSP90, a known regulator of HIV transcription, recapitulates the quiescence and latency phenotypes of hypothermia, suggesting that hypothermia and HSP90 inhibition may regulate these processes by similar mechanisms. In summary, these studies describe a novel model for studying HIV-1 latency in human primary cells maintained in a quiescent state. IMPORTANCE Human immunodeficiency virus type 1 (HIV-1) establishes a persistent infection for which there remains no feasible cure. Current approaches are unable to clear the virus despite decades of therapy due to the existence of latent reservoirs of integrated HIV-1, which can reactivate and contribute to viral rebound following treatment interruption. Previous clinical attempts to reactivate the latent reservoirs in an individual so that they can be eliminated by the immune response or viral cytopathic effect have failed, indicating the need for a better understanding of the processes regulating HIV-1 latency. Here we characterize a novel in vitro model of HIV-1 latency in primary hematopoietic stem and progenitor cells isolated from human cord blood that may better recapitulate the behavior of latently infected cells in vivo. This model can be used to study mechanisms regulating latency and potential therapeutic approaches to reactivate latent infections in quiescent cells. [ABSTRACT FROM AUTHOR]

Some species of invertebrates especially bryozoans (Bryozoa syn. Ectoprocta) and marine sponges (Porifera) are very important sources of pharmacologically exploitable compounds. These substances are probably produced to protect themselves from fish predators and may be an advantage in competition. The real sources of compounds with these antipredatory effects are probably not marine invertebrates themselves, but microscopic symbionts or food which they feed on. Bryostatins from bryozoan species Bugula neritina are produced by a bacterial symbiont called Candidatus Endobugula sertula. They have significant anti-cancer effects, but also other therapeutic benefits. Compounds with the structure of bryostatins were also discovered in some other invertebrates. Sponges are a source of many compounds, e.g., ara-A (vidarabine), manzamine, lasonolides, spongistatins, peloruside and others with antimicrobial, anti-cancer, immunosuppressive and similar activities. Other important sources of compounds with medical effects are tunicates (Tunicata syn. Urochordata) and some snails (Mollusca). One drug was developed from tunicates - Yondelis against refractory soft-tissue sarcomas. Certain other drugs originate from snails: e.g., prialt, which acts against chronic pain in spinal cord injury.

PKC signaling is critical for the non-toxic degradation of amyloid precursor protein (APP) and inhibition of GSK3β, which controls phosphorylation of tau protein in Alzheimer's disease (AD). Thus the misregulation of PKC signaling could contribute to the origins of AD. Bryostatin, a potent PKC modulator, has the potential to ameliorate both the neurodegeneration and the recent memory loss associated with AD. As reported herein bryostatin and a potent synthetic analog (picolog) are found to cause stimulation of non-amyloidogenic pathways by increasing α-secretase activity and thus lowering the amount of toxic Aβ produced. Both bryostatin and picolog increased the secretion of the α-secretase product (s-APP-α) of APP at sub-nanomolar to nanomolar concentrations. A peripheral AD-Biomarker has previously been autopsy-validated. This Biomarker, based on bradykinin-induced differential phosphorylation of Erk1 and Erk2, has been used here to test the therapeutic efficacy both for bryostatin and picolog. Both of these PKC activators are then shown to convert the AD Erk1/2 phenotype of fibroblasts into the phenotype of “normal” control skin fibroblasts. This conversion occurred for both the abnormal Erk1/2 phenotype induced by application of Aβ1–42 to the fibroblasts or the phenotype observed for fibroblasts of AD patients. The Aβ1–42-induction, and PKC modulator reversal of the AD Erk1/2 biomarker phenotype demonstrate the AD-Biomarker's potential to monitor both disease progression and treatment response. Additionally, this first demonstration of the therapeutic potential in AD of a synthetically accessible bryostatin analog warrants further preclinical advancement.

Previously, we reported that salicylate-based analogs of bryostatin protect cells from chikungunya virus (CHIKV)-induced cell death. Interestingly, ‘capping’ the hydroxyl group at C26 of a lead bryostatin analog, a position known to be crucial for binding to and modulation of protein kinase C (PKC), did not abrogate the anti-CHIKV activity of the scaffold, putatively indicating the involvement of a pathway independent of PKC. The work detailed in this study demonstrates that salicylate-derived analog 1 and two capped analogs ( 2 and 3 ) are not merely cytoprotective compounds, but act as selective and specific inhibitors of CHIKV replication. Further, a detailed comparative analysis of the effect of the non-capped versus the two capped analogs revealed that compound 1 acts both at early and late stages in the chikungunya virus replication cycle, while the capped analogs only interfere with a later stage process. Co-dosing with the PKC inhibitors sotrastaurin and Gö6976 counteracts the antiviral activity of compound 1 without affecting that of capped analogs 2 and 3 , providing further evidence that the latter elicit their anti-CHIKV activity independently of PKC. Remarkably, treatment of CHIKV-infected cells with a combination of compound 1 and a capped analog resulted in a pronounced synergistic antiviral effect. Thus, these salicylate-based bryostatin analogs can inhibit CHIKV replication through a novel, yet still elusive, non-PKC dependent pathway. [ABSTRACT FROM AUTHOR]

We describe a convergent synthesis of a bryostatin analogue in which the natural A- and B-ring pyrans have been replaced by phenyl rings. The new analogue exhibited PMA like behavior in cell assays, but failed to maintain high affinity binding for PKC, despite retaining an unaltered C-ring ‘binding domain’ [ABSTRACT FROM AUTHOR]

In all mammalian species studied to date, the initiation of oocyte activation is orchestrated through alterations in intracellular calcium (Ca(2+)) signaling. Upon sperm binding to the oocyte plasma membrane, a sperm-associated phospholipase C (PLC) isoform, PLC zeta (PLCζ), is released into the oocyte cytoplasm. PLCζ hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2) to produce diacylglycerol (DAG), which activates protein kinase C (PKC), and inositol 1,4,5-trisphosphate (IP3), which induces the release of Ca(2+) from endoplasmic reticulum (ER) Ca(2+) stores. Subsequent Ca(2+) oscillations are generated that drive oocyte activation to completion. Ca(2+) ionophores such as ionomycin have been successfully used to induce artificial human oocyte activation, facilitating fertilization during intra-cytoplasmic sperm injection (ICSI) procedures. Early studies have also demonstrated that the PKC activator phorbol 12-myristate 13-acetate (PMA) acts synergistically with Ca(2+) ionophores to induce parthenogenetic activation of mouse oocytes. Interestingly, the Ca(2+)-induced signaling cascade characterizing sperm or chemically-induced oocyte activation, i.e. the "shock and live" approach, bears a striking resemblance to the reactivation of latently infected HIV-1 viral reservoirs via the so called "shock and kill" approach, a method currently being pursued to eradicate HIV-1 from infected individuals. PMA and ionomycin combined, used as positive controls in HIV-1 latency reversal studies, have been shown to be extremely efficient in reactivating latent HIV-1 in CD4(+) memory T cells by inducing T cell activation. Similar to oocyte activation, T cell activation by PMA and ionomycin induces an increase in intracellular Ca(2+) concentrations and activation of DAG, PKC, and downstream Ca(2+)-dependent signaling pathways necessary for proviral transcription. Interestingly, AMPK, a master regulator of cell metabolism that is activated thorough the induction of cellular stress (e.g. increase in Ca(2+) concentration, reactive oxygen species generation, increase in AMP/ATP ratio) is essential for oocyte maturation, T cell activation, and mitochondrial function. In addition to the AMPK kinase LKB1, CaMKK2, a Ca(2+)/calmodulin-dependent kinase that also activates AMPK, is present in and activated on T cell activation and is also present in mouse oocytes and persists until the zygote and two-cell stages. It is our hypothesis that AMPK activation represents a central node linking T cell activation-induced latent HIV-1 reactivation and both physiological and artificial oocyte activation. We further propose the novel observation that various compounds that have been shown to reactivate latent HIV-1 (e.g. PMA, ionomycin, metformin, bryostatin, resveratrol, etc.) or activate oocytes (PMA, ionomycin, ethanol, puromycin, etc.) either alone or in combination likely do so via stress-induced activation of AMPK. [ABSTRACT FROM AUTHOR]

Bryostatin-1 is a marine natural product that has demonstrated medicinal activity in pre-clinical and clinical trials for the treatment of cancer, Alzheimer’s disease, effects of stroke, and HIV. In this study, iron–bryostatin-1 was obtained using a pharmaceutical aquaculture technique developed by our lab that cultivates marine bacteria for marine natural product extraction. Analytical measurements 1 H and 13 C NMR, mass spectrometry, and flame atomic absorption were utilized to confirm the presence of an iron–bryostatin-1 complex. The iron–bryostatin-1 complex produced was then tested against the National Cancer Institute’s 60 cell line panel. Adding iron to bryostatin-1 lowered the anti-cancer efficacy of the compound. [ABSTRACT FROM AUTHOR]

Disease ailments are changing the patterns, and the new diseases are emerging due to changing environments. The enormous growth of world population has overburdened the existing resources for the drugs. And hence, the drug manufacturers are always on the lookout for new resources to develop effective and safe drugs for the increasing demands of the world population. Seventy-five percentage of earth's surface is covered by water but research into the pharmacology of marine organisms is limited, and most of it still remains unexplored. Marine environment represents countless and diverse resource for new drugs to combat major diseases such as cancer or malaria. It also offers an ecological resource comprising a variety of aquatic plants and animals. These aquatic organisms are screened for antibacterial, immunomodulator, anti-fungal, anti-inflammatory, anticancer, antimicrobial, neuroprotective, analgesic, and antimalarial properties. They are used for new drug developments extensively across the world. Marine pharmacology offers the scope for research on these drugs of marine origin. Few institutes in India offer such opportunities which can help us in the quest for new drugs. This is an extensive review of the drugs developed and the potential new drug candidates from marine origin along with the opportunities for research on marine derived products. It also gives the information about the institutes in India which offer marine pharmacology related courses. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder. Current approved drugs may only ameliorate symptoms in a restricted number of patients and for a restricted period of time. Currently, there is a translational research challenge into identifying the new effective drugs and their respective new therapeutic targets in AD and other neurodegenerative disorders. In this review, selected examples of marine-derived compounds in neurodegeneration, specifically in AD field are reported. The emphasis has been done on compounds and their possible relevant biological activities. The proposed drug development paradigm and current hypotheses should be accurately investigated in the future of AD therapy directions although taking into account successful examples of such approach represented by Cytarabine, Trabectedin, Eribulin and Ziconotide. We review a complexity of the translational research for such a development of new therapies for AD. Bryostatin is a prominent candidate for the therapy of AD and other types of dementia in humans. [ABSTRACT FROM AUTHOR]

Blood–brain barrier (BBB) disruption and hemorrhagic transformation (HT) following ischemic/reperfusion injury contributes to post-stroke morbidity and mortality. Bryostatin, a potent protein kinase C (PKC) modulator, has shown promise in treating neurological injury. In the present study, we tested the hypothesis that administration of bryostatin would reduce BBB disruption and HT following acute ischemic stroke; thus, prolonging the time window for administering recombinant tissue plasminogen activator (r-tPA). Acute cerebral ischemia was produced by reversible occlusion of the right middle cerebral artery (MCAO) in 18–20-month-old female rats using an autologous blood clot with delayed r-tPA reperfusion. Bryostatin (or vehicle) was administered at 2 h post-MCAO and r-tPA was administered at 6 h post-MCAO. Functional assessment, lesion volume, and hemispheric swelling measurements were performed at 24 h post-MCAO. Assessment of BBB permeability, measurement of hemoglobin, assessment of matrix metalloproteinase (MMP) levels by gel zymography, and measurement of PKCε, PKCα, PKCδ expression by western blot were conducted at 24 h post-MCAO. Rats treated with bryostatin prior to r-tPA administration had decreased mortality and hemispheric swelling when compared with rats treated with r-tPA alone. Administration of bryostatin also limited BBB disruption and HT and down-regulated MMP-9 expression while up-regulating PKCε expression at 24 h post-MCAO. Bryostatin administration ameliorates BBB disruption and reduces the risk of HT by down-regulating MMP-9 activation and up-regulating PKCε. In this proof-of-concept study, bryostatin treatment lengthened the time-to-treatment window and enhanced the efficacy and safety of thrombolytic therapy. [ABSTRACT FROM AUTHOR]

Background: Early onset dementias have variable clinical presentations and are often difficult to diagnose. We established a family pedigree that demonstrated consistent recurrence of very early onset dementia in successive generations.Objective and Method: In order to refine the diagnosis in this family, we sequenced the exomes of two affected family members and relied on discrete filtering to identify disease genes and the corresponding causal variants.Results: Among the 720 nonsynonymous single nucleotide polymorphisms (SNPs) shared by two affected members, we found a C to T transition that gives rise to a Thr147Ile missense substitution in the presenilin 1 (PS1) protein. The presence of this same mutation in a French early-onset Alzheimer's disease family, other affected members of the family, and the predicted high pathogenicity of the substitution strongly suggest that it is the causal variant. In addition to exceptionally young age of onset, we also observed significant limb spasticity and early loss of speech, concurrent with progression of dementia in affected family members. These findings extend the clinical presentation associated with the Thr147Ile variant. Lastly, one member with the Thr147Ile variant was treated with the PKC epsilon activator, bryostatin, in a compassionate use trial after successful FDA review. Initial improvements with this treatment were unexpectedly clear, including return of some speech, increased attentional focus, ability to swallow, and some apparent decrease in limb spasticity.Conclusions: Our findings confirm the role of the PS1 Thr147Ile substitution in Alzheimer's disease and expand the clinical phenotype to include expressive aphasia and very early onset of dementia. [ABSTRACT FROM AUTHOR]

Highlights: [•] Bryostatin enhanced Brown Norway rat spatial learning and memory. [•] Bryostatin significantly increased the frequency and amplitude of sIPSC. [•] Inhibition of interneurons’ excitation blocked Bryostatin’s effects on sIPSCs. [•] Bryostatin effect is through activating the PKCα & ε-dependent pathway. [•] Bryostatin can switch paired-pulse depression to facilitation. [Copyright &y& Elsevier]

Highlights: [•] The critical role of PKC activation for memory enhancement was examined. [•] Twenty paired CS–US presentations resulted in STM and LTM. [•] Pre-exposure to PKC activator formed STM with 5 paired CS–US presentations. [•] Pre-incubation with PKC activator facilitated STM into LTM. [•] Pre-incubation with PKC inhibitor failed to form both STM and LTM. [ABSTRACT FROM AUTHOR]

Alzheimer’s disease (AD) is a multifactorial neurodegenerative disorder. Current approved drugs may only ameliorate symptoms in a restricted number of patients and for a restricted period of time. Currently, there is a translational research challenge into identifying the new effective drugs and their respective new therapeutic targets in AD and other neurodegenerative disorders. In this review, selected examples of marine-derived compounds in neurodegeneration, specifically in AD field are reported. The emphasis has been done on compounds and their possible relevant biological activities. The proposed drug development paradigm and current hypotheses should be accurately investigated in the future of AD therapy directions although taking into account successful examples of such approach represented by Cytarabine, Trabectedin, Eribulin and Ziconotide. We review a complexity of the translational research for such a development of new therapies for AD. Bryostatin is a prominent candidate for the therapy of AD and other types of dementia in humans.

Highly active antiretroviral therapy (HAART) decreases plasma viremia below the limits of detection in the majority of HIV-infected individuals, thus serving to slow disease progression. However, HAART targets only actively replicating virus and is unable to eliminate latently infected, resting CD4+ T cells. Such infected cells are potentially capable of reinitiating virus replication upon cessation of HAART, thus leading to viral rebound. Agents that would eliminate these reservoirs, when used in combination with HAART, could thus provide a strategy for the eradication of HIV. Prostratin is a preclinical candidate that induces HIV expression from latently infected CD4+ T cells, potentially leading to their elimination through a virus-induced cytopathic effect or host anti-HIV immunity. Here, we report the synthesis of a series of designed prostratin analogs and report in vitro and ex vivo studies of their activity relevant to induction of HIV expression. Members of this series are up to 100-fold more potent than the preclinical lead (prostratin) in binding to cell-free PKC, and in inducing HIV expression in a latently infected cell line and prostratin-like modulation of cell surface receptor expression in primary cells from HIV-negative donors. Significantly, selected members were also tested for HIV induction in resting CD4+ T cells isolated from infected individuals receiving HAART and were found to exhibit potent induction activity. These more potent agents and by extension related tunable analogs now accessible through the studies described herein should facilitate research and preclinical advancement of this strategy for HIV/AIDS eradication. [ABSTRACT FROM AUTHOR]

Abstract: The role of the C8 gem-dimethyl group in the A-ring of bryostatin 1 has been examined through chemical synthesis and biological evaluation of a new analogue. Assays for biological function using U937, K562, and MV4-11 cells as well as the profiles for downregulation of PKC isozymes revealed that the presence of this group is not a critical determinant for the unique pattern of biological activity of bryostatin. [Copyright &y& Elsevier]

Protein kinase C (PKC) isozymes are promising targets for anticancer therapy. Bryostatin-1 (bryo-1), a unique PKC activator with little tumor-promoting activity, is currently in clinical trials for the treatment of cancer. However, its limited availability from natural sources and its synthetic complexity have hampered studies of its mode of action and structural optimization as a therapeutic agent. The development of synthetically more accessible compounds with bryo-1-like activities is thus needed. Recently, we developed a simple and less lipophilic analogue of tumor-promoting aplysiatoxin (ATX) (aplog-1) as a promising lead for bryo-1-like anticancer drugs. Structure--activity studies suggested that local hydro - phobicity around the spiroketal moiety of aplog-1 is a crucial determinant of its antiproliferative activity. The hydrophobic analogue (12,12-dimethyl-aplog-1) displayed more potent antiproliferative activity. Moreover, it showed little tumor-promoting activity and even suppressed the tumor promotion by 12-O-tetradecanoylphorbol 13-acetate (TPA) in vivo and in vitro. Aplog-1 and bryo-1 bound selectively to novel PKC isozymes (δ, η, and ϑ) while tumor promoters bound to both conventional and novel PKC isozymes. These results suggest that the unique biological activities of aplog-1 and bryo-1 are ascribable in part to the ability to bind to PKCδ, but weak binding to conventional PKC isozymes might also be important. [ABSTRACT FROM AUTHOR]

Protein kinase C (PKC) isozymes are widely recognized as targets for anticancer therapy, and recent investigations demonstrated that PKC activators are potential therapeutic candidates for Alzheimer's disease and acquired immune deficiency syndrome. However, concerns exist about their therapeutic uses because most PKC activators are potent tumor promoters. Bryostatin 1 (bryo-1) is a unique PKC activator with little tumor-promoting activities. Bryo-1 is currently undergoing clinical trials for the treatment of cancer. However, its limited availability from natural sources and difficulty in the synthesis hamper further studies on its mode of action and structural optimization. Although excellent practical methods for synthesizing several bryo-1-related compounds have been developed, the identification of synthetically more accessible compounds with bryo-1-like activity also provides a promising way to circumvent the problem of supply. The authors focused on the bryo-1's unique mechanism of activating PKCδ that plays a tumor suppressor role, and found that a simple and less lipophilic analogue (aplog-1) of the tumor-promoting aplysiatoxin showed PKCδ-activating behavior similar to bryo-1. Aplog-1 was easily synthesized in only 22 steps using standard reactions. Moreover, its tumor-promoting activity in vitro was very weak, and its cell growth-inhibitory activities were comparable to those of bryo-1. These data suggest that aplog-1 could become another therapeutic lead for cancer. © 2010 Wiley Periodicals, Inc. Med Res Rev, 32, No. 3, 518-535, 2012 [ABSTRACT FROM AUTHOR]

Some species of invertebrates especially bryozoans (Bryozoa syn. Ectoprocta) and marine sponges (Porifera) are very important sources of pharmacologically exploitable compounds. These substances are probably produced to protect themselves from fish predators and may be an advantage in competition. The real sources of compounds with these antipredatory effects are probably not marine invertebrates themselves, but microscopic symbionts or food which they feed on. Bryostatins from bryozoan species Bugula neritina are produced by a bacterial symbiont called Candidatus Endobugula sertula. They have significant anti-cancer effects, but also other therapeutic benefits. Compounds with the structure of bryostatins were also discovered in some other invertebrates. Sponges are a source of many compounds, e.g., ara-A (vidarabine), manzamine, lasonolides, spongistatins, peloruside and others with antimicrobial, anti-cancer, immunosuppressive and similar activities. Other important sources of compounds with medical effects are tunicates (Tunicata syn. Urochordata) and some snails (Mollusca). One drug was developed from tunicates - Yondelis against refractory soft-tissue sarcomas. Certain other drugs originate from snails: e.g., prialt, which acts against chronic pain in spinal cord injury. [ABSTRACT FROM AUTHOR]

Background: More than 50% of patients undergoing lifelong suppressive antiviral treatment for HIV-1 infection develop minor HIV-1-associated neurocognitive disorders. Neurological complications during HIV-1 infection are the result of direct neuronal damage by proinflammatory products released from HIV-1-infected or -uninfected activated lymphocytes, monocytes, macrophages, microglia and astrocytes. The specific pro-inflammatory products and their roles in neurotoxicity are far from clear. We investigated proinflammatory cytokines and chemokines in the cerebrospinal fluid (CSF) of HIV-demented (HIV-D) and HIV-nondemented (HIV-ND) patients and studied their affect on neuroglial toxicity. Methods and results: Bioplex array showed elevated levels of signatory chemokines or cytokines (IL-6, IFN-γ, CXCL10, MCP-1 and PDGF) in the CSF of HIV-D patients (n = 7) but not in that of HIV-ND patients (n = 7). Among the signatory cytokines and chemokines, CXCL10 was distinctly upregulated in-vitro in HIV-1 (NLENG1)-activated human fetal astrocytes, HIV-1 (Ba-L)-infected macrophages, and HIV-1 (NLENG1)-infected lymphocytes. Virus-infected macrophages also had increased levels of TNF-α. Consistently, human fetal astrocytes treated with HIV-1 and TNF-α induced the signatory molecules. CXCL10 in combination with HIV-1 synergistically enhanced neuronal toxicity and showed chemotactic activity (~ 40 fold) for activated peripheral blood mononuclear cells (PBMC), suggesting the intersection of signaling events imparted by HIV-1 and CXCL10 after binding to their respective surface receptors, CXCR4 and CXCR3, on neurons. Blocking CXCR3 and its downstream MAP kinase (MAPK) signaling pathway suppressed combined CXCL10 and HIV-1-induced neurotoxicity. Bryostatin, a PKC modulator and suppressor of CXCR4, conferred neuroprotection against combined insult with HIV-1 and CXCL10. Bryostatin also suppressed HIV-1 and CXCL10-induced PBMC chemotaxis. Although, therapeutic targeting of chemokines in brain may have adverse consequences on the host, current findings and earlier evidence suggest that CXCL10 could strongly impede neuroinflammation. Conclusion: We have demonstrated induction of CXCL10 and other chemokines/cytokines during HIV-1 infection in the brain, as well as synergism of CXCL10 with HIV-1 in neuronal toxicity, which was dampened by bryostatin. [ABSTRACT FROM AUTHOR]

Abstract: The zinc(II) iodide mediated ‘ene’ reaction between (4R)-4,5-bis-(tert-butyldimethylsilyloxy)-2-(trimethylsilylmethyl)pent-1-ene (43) and (5S,7R,9S)-5,11-dibenzyloxy-4,4-dimethyl-7,9-dihydroxy-7,9-O-isopropylideneundec-1-yn-3-one (53) gave the (E)-vinylsilane 54 with excellent stereoselectivity. Simultaneous deprotection and cyclisation via a stereoselective oxy-Michael reaction gave the bicyclic acetal 57 after treatment with trimethyl orthoformate. A synthesis of the ester 60 corresponding to the C(1)–C(16) fragment of the bryostatins was then completed by O-silylation, oxidative cleavage of the methylene group and a stereoselective condensation of the resulting ketone 59 with the chiral phosphonate 61. [Copyright &y& Elsevier]

Abstract: The synthesis and biological evaluation of the first members of a new series of designed bryostatin A-ring analogues (bryologs) are described. An advanced intermediate is produced that allows for step economical access to diverse analogs. The first of these analogues, bearing side chains of completely different polarities from alkyl to hydroxyl and carboxyl functionalities, were evaluated. All exhibit potent protein kinase C binding (54.7–2.4nM) with affinities increasing with decreasing side chain polarity. This series of bryostatin analogues demonstrates that A-ring surrogates can indeed be used for tuning pharmacophore and ADME characteristics as needed to improve bryolog function. [Copyright &y& Elsevier]

Abstract: A new ultrasensitive fluorescent derivatization procedure for chromatographic analysis of primary, secondary, and nonpolar tertiary alcohols is described. The procedure uses Bodipy FL in basic dichloromethane solution with Mukaiyama’s reagent (2-chloro-1-methylpyridinium iodide) to form highly fluorescent ester derivatives that can be separated by silica normal-phase high-performance liquid chromatography (HPLC). Rhodamine WT and Oregon green 488 were also useful derivatization reagents. The detection limit for detection of cholesterol and bryostatin by Bodipy FL was less than 1fmol. The reaction conditions are gentle enough that low concentrations of unstable alcohols such as bryostatin 1 can be measured. [Copyright &y& Elsevier]

The article presents a study on the synthesis and biological evaluation of a dimethyl derivative of Aplog-1, an anti-proliferative analog of the tumor promoter aplysiatoxin. It notes that the Aplog-1 (3) derivative was effective in inhibiting cancer cell growth and binding to particular protein kinases. It also notes that the derivative shows potential for anti-cancer drugs.

Abstract: Purpose: Pharmacologic differentiating agents have had relatively limited clinical success outside of the use of ATRA in acute promyelocytic leukemia and DNA methyltransferase inhibitors in myelodysplastic syndromes. The differentiating effects of such agents can be enhanced in combination with lineage-specific growth factors. We developed a dose finding trial to assess toxicity, differentiating activity, and clinical impact of the combination of bryostatin-1 and GM-CSF. Experimental design: Patients with poor risk myeloid malignancies were eligible to enroll in a dose finding study of continuous infusion bryostatin-1 combined with a fixed dose of daily GM-CSF. Toxicities were graded per NCI CTC version 2.0 and pharmacokinetic and correlative study samples were obtained to assess the combination''s clinical and biologic differentiating effects. Results: Thirty-two patients were treated with the combination therapy and the dose determined to be most suitable for study in a larger trial was continuous infusion broystatin-1 at 16μg/m2 for 14 days and subcutaneous GM-CSF at 125μg/m2 daily for 14 days every 28 days. Arthralgias and myalgias limited further dose escalation. Clinically, the combination impacted differentiation with improvement of absolute neutrophil counts (p =0.0001) in the majority of patients. Interestingly, there were two objective clinical responses, including a CR after a single cycle. Both the bryostatin-1 plasma concentrations and the correlative studies supported biologic activity of the combination at the doses where clinical responses were observed. Conclusions: Combining growth factors with pharmacologic differentiating agents may increase their clinical effectiveness and further studies should focus on such combinations. [Copyright &y& Elsevier]

Therapeutics for cerebral ischemia/hypoxia, which often results in ischemic stroke in humans, are a global unmet medical need. Here, we report that bryostatin-1, a highly potent protein kinase C (PKC) activator, interrupts pathophysiological molecular cascades and apoptosis triggered by cerebral ischemia/hypoxia, enhances neurotrophic activity, and induces synaptogenesis in rats. This postischemic therapeutic approach is further shown to preserve learning and memory capacity even 4 months later as well as long-term memory induced before the ischemic event. Our results of electromicroscopic and immunohistochemical analyses of neuronal and synaptic ultra-structure are consistent with a PKC-mediated synaptic remodeling and repair process that confers long-lasting preservation of spatial learning and memory before and after the cerebral ischemic/hypoxic event, suggesting a previously undescribed therapeutic modality for cerebral ischemia/hypoxia and ischemic stroke. [ABSTRACT FROM AUTHOR]

Abstract: PKC signaling is critical for the non-toxic degradation of amyloid precursor protein (APP) and inhibition of GSK3β, which controls phosphorylation of tau protein in Alzheimer''s disease (AD). Thus the misregulation of PKC signaling could contribute to the origins of AD. Bryostatin, a potent PKC modulator, has the potential to ameliorate both the neurodegeneration and the recent memory loss associated with AD. As reported herein bryostatin and a potent synthetic analog (picolog) are found to cause stimulation of non-amyloidogenic pathways by increasing α-secretase activity and thus lowering the amount of toxic Aβ produced. Both bryostatin and picolog increased the secretion of the α-secretase product (s-APP-α) of APP at sub-nanomolar to nanomolar concentrations. A peripheral AD-Biomarker has previously been autopsy-validated. This Biomarker, based on bradykinin-induced differential phosphorylation of Erk1 and Erk2, has been used here to test the therapeutic efficacy both for bryostatin and picolog. Both of these PKC activators are then shown to convert the AD Erk1/2 phenotype of fibroblasts into the phenotype of “normal” control skin fibroblasts. This conversion occurred for both the abnormal Erk1/2 phenotype induced by application of Aβ1–42 to the fibroblasts or the phenotype observed for fibroblasts of AD patients. The Aβ1–42-induction, and PKC modulator reversal of the AD Erk1/2 biomarker phenotype demonstrate the AD-Biomarker''s potential to monitor both disease progression and treatment response. Additionally, this first demonstration of the therapeutic potential in AD of a synthetically accessible bryostatin analog warrants further preclinical advancement. [Copyright &y& Elsevier]

Abstract: In Lymnaea, aerial respiration can be operantly conditioned and depending on the training procedure employed two forms of memory can result: intermediate-term (ITM) and long-term memory (LTM). ITM, which persists for 3h, is dependent on de novo protein synthesis whilst LTM, which persists for at least 24h, is dependent on both de novo protein synthesis and altered gene activity. A single 0.5h training session (i.e. ITM-training) leaves behind a residual molecular memory trace, which a second bout of ITM-training can activate and boost it to a LTM. Here we extend this finding to show that either inhibiting protein phosphatase activity with okadaic acid (1μM), or increasing protein kinase C (PKC) activity and therefore protein phosphorylation with bryostatin (0.25ng/mL) treatment prior to ITM-training, results in a LTM. However, following right pedal dorsal 1 (RPeD1) soma ablation neither of these treatments are effective in producing LTM following ITM-training, indicating transcription is a necessity. These findings suggest that the balance between phosphorylation and dephosphorylation in neurons is a key factor for LTM formation. [Copyright &y& Elsevier]

Global cerebral ischemia/hypoxia, as can occur during human stroke, damages brain neural networks and synaptic functions. The recently demonstrated protein kinase C (PKC) activation-induced synaptogenesis in rat hippocampus suggested the potential of PKC-mediated antiapoptosis and synaptogenesis during conditions of neurodegeneration. Consequently, we examined the effects of chronic bryostatin-i, a PKC activator, on the cerebral ischemia/hypoxia-induced impairment of synapses and neurotrophic activity in the hippocampal CAl area and on hippocampus-dependent spatial learning and memory. Postischemiclhypoxic bryostatin-i treatment effectively rescued ischemia-induced deficits in synaptogenesis, neurotrophic activity, and spatial learning and memory. These results highlight a neuroprotective signaling pathway, as well as a therapeutic strategy with an extended time window for reducing brain damage due to stroke by activating particular PKC isozymes. [ABSTRACT FROM AUTHOR]

Bryostatin structures share a commonality of a central bryophan ring, but each differs due to two groups (R1 and R2) that are attached to the bryophan ring via ester bonds. This research examines the impact that conditions such as UV light, acidic and basic conditions can have on the bryostatin structure in the presence of octanoic acid and water. Mass spectrometry (MS) measurements suggest that bryostatin can easily rearrange into various structures under natural conditions by reacting with carboxylates that are ubiquitous in nature. A second set of measurements suggest bryostatin can be hydrolyzed by water, a reaction that has significant implications in both medicinal applications and extraction procedures. [ABSTRACT FROM AUTHOR]

In this computational study, geometric factors are calculated by applying semi-empirical methods (PM3) that support experimental evidence from this lab where bryostatins can bind trivalent iron with six Fe-O bonds forming an octahedral geometry. The geometric factors are calculated for all 20 structures (Fe3+ bound to bryostatin 1-20) as a neutral, monovalent, and divalent species. The average Fe-O bond distances and bond angles are compared to those of known marine and terrestrial siderophores. From these two data sets, we then examined other known marine natural products (MNPs) that can form a hexavalent complex with six Fe-O bonds and draw conclusions about their potential biological role as marine siderophores. This computational data indicates that Fe(III) strongly bonds to a host of MNPs, increasing their water solubility, contracting their structure, hence allowing transport through cell membranes more readily, and in some cases, stabilizing ester bonds that are susceptible to hydrolysis. It is argued that administering medicinally bryostatin, its analogs or other MNPs as a ferric complex, holds some fundamental chemical advantages compared to its administration as a neutral uncomplexed species. [ABSTRACT FROM AUTHOR]

Using both scanning confocal and electron microscopic morphometric measurements, we analyzed single dendritic spines of CA1 pyramidal cells in the hippocampi of water maze-trained rats vs. controls. Two days after completion of all training, we observed a memory-specific increase in the number of mushroom spines—all of which make synaptic contacts—but not in the numbers of filopodia or stubby or thin spines, as quantified with double-blind protocols in both scanning confocal and electron microscopic images. This memory-specific increase of mushroom spine number was enhanced by the PKC activator and candidate Alzheimer's disease therapeutic bryostatin, blocked by the PKCα-isozyme blocker Ro 31-8220, and accompanied by increases in the number of "perforated" postsynaptic densities, increased numbers of presynaptic vesicles, and the increased occurrence of double-synapse presynaptic boutons associated with the mushroom spines. These and other confocally imaged immunohistochemical results described here involving PKC substrates indicate that individual mushroom spines provide structural storage sites for long-term associative memory and sites for memory-specific synaptogenesis that involve PKC-regulated changes of spine shape, as well as PKC-regulated changes of pre- and postsynaptic ultrastructure. [ABSTRACT FROM AUTHOR]