The protein 14-3-3: A functionally versatile molecule in Giardia duodenalis

Role of anti-Giardia recombinant cyst wall protein IgG polyclonal antibodies in diagnosis and protection

Giardia duodenalis (G. duodenalis) is an infectious protozoan that has a global distribution especially in the hot climate. Around 200 million people are infected worldwide annually by Giardia, but infection is not always accompanied by symptoms, especially in endemic countries. Using traditional microscopy techniques in diagnosis, both in stool and water samples were less sensitive when compared to immunological methods; and the need for new diagnostic methods was necessary. Also, protection from infection is required in endemic areas. Therefore, the study aimed to produce anti- G. duodenalis IgG polyclonal antibodies (pAbs) by immunizing rabbit by G. duodenalis cyst recombinant protein. The produced antibodies were evaluated in the detection of G. duodenalis antigens in patients' stool and water samples from endemic areas across River Nile; where pAbs were used as a coating and a peroxidase conjugate antibody in sandwich ELISA. Moreover, pAbs were tested for the protection of mice from giardiasis. Sandwich ELISA using pAb has succeeded in the detection of G. duodenalis coproantigens in stool samples by a sensitivity of 97% and a specificity of 92.72%. Moreover, G. duodenalis cyst was detected in only seven water samples by ordinary microscopy; while sandwich ELISA revealed nineteen positive results. IgG pAb (1/200 µg/ml) protected mice from giardiasis; which was evident from the reduction in cysts and trophozoites numbers. We recommended the use of sandwich ELISA to monitor water quality, investigate environmental contamination and diagnosis in patients' stools. The pAbs can be prepared in large amount and used in field diagnosis and protection. This will help in the early diagnosis of G. duodenalis in water, which in turn can control outbreaks in rural areas.

Analysis of immune response in BALB/c mice immunized with recombinant plasmids pMZ-X3-Ts14-3-3.3 and pMZ-X3-sp-Ts14-3-3.3 of Taenia solium

There is a lack of vaccine against human cysticercosis, thus making a huge population at the risk of infection. In this study, we chose a novel potential antigen molecule Taenia solium 14-3-3.3 (Ts14-3-3.3) and optimized it as sp-Ts14-3-3.3 (sp is immunoglobulin H chain V-region precursor, partial) in order to construct recombinant plasmids pMZ-X3-Ts14-3-3.3 and pMZ-X3-sp-Ts14-3-3.3. BALB/c mice were divided into four groups for immunization: pMZ-X3-Ts14-3-3.3, pMZ-X3-sp-Ts14-3-3.3, pMZ-X3 plasmid control group and PBS control group. Compared with two control groups, the proliferation level of splenic lymphocytes increased significantly in pMZ-X3-Ts14-3-3.3 and pMZ-X3-sp-Ts14-3-3.3 groups and reached the maximum in week 6. And the same case arose as cytokines associated with Th1 response, IFN-γ, and IL-2 while those with Th2 response, IL-4, IL-10 went up and reached the maximum in week 4. The levels of serum specific IgG, IgG1 and IgG2a rose and reached the maximum in week 6, 4 and 6, respectively. Meanwhile, the proportion of CD4⁺/CD8⁺ splenic T lymphocytes increased and reached the peak in week 6. The results indicated that the recombinant plasmids pMZ-X3-Ts14-3-3.3 and pMZ-X3-sp-Ts14-3-3.3 can induce specific cellular and humoral immune responses in BALB/c mice with immunization. Notably, the recombinant plasmid pMZ-X3-sp-Ts14-3-3.3 has a better immune effect, which proves that Ts14-3-3.3 enjoys a higher possibility as a potential antigen molecule to T. solium vaccine.

The Nitrobenzoxadiazole Derivative NBDHEX Behaves as Plasmodium falciparum Gametocyte Selective Inhibitor with Malaria Parasite Transmission Blocking Activity

This work describes the activity of 6-((7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)thio)hexan-1-ol (NBDHEX) and of its newly identified carboxylic acid metabolite on the human malaria parasite Plasmodium falciparum. NBDHEX has been previously identified as a potent cytotoxic agent against murine and human cancer cells as well as towards the protozoan parasite Giardia duodenalis. We show here that NBDHEX is active in vitro against all blood stages of P. falciparum, with the rare feature of killing the parasite stages transmissible to mosquitoes, the gametocytes, with a 4-fold higher potency than that on the pathogenic asexual stages. This activity importantly translates into blocking parasite transmission through the Anopheles vector in mosquito experimental infections. A mass spectrometry analysis identified covalent NBDHEX modifications in specific cysteine residues of five gametocyte proteins, possibly associated with its antiparasitic effect. The carboxylic acid metabolite of NBDHEX retains the gametocyte preferential inhibitory activity of the parent compound, making this novel P. falciparum transmission-blocking chemotype at least as a new tool to uncover biological processes targetable by gametocyte selective drugs. Both NBDHEX and its carboxylic acid metabolite show very limited in vitro cytotoxicity on VERO cells. This result and previous evidence that NBDHEX shows an excellent in vivo safety profile in mice and is orally active against human cancer xenografts make these molecules potential starting points to develop new P. falciparum transmission-blocking agents, enriching the repertoire of drugs needed to eliminate malaria.

14-3-3σ and Its Modulators in Cancer

14-3-3σ is an acidic homodimer protein with more than one hundred different protein partners associated with oncogenic signaling and cell cycle regulation. This review aims to highlight the crucial role of 14-3-3σ in controlling tumor growth and apoptosis and provide a detailed discussion on the structure-activity relationship and binding interactions of the most recent 14-3-3σ protein-protein interaction (PPI) modulators reported to date, which has not been reviewed previously. This includes the new fusicoccanes stabilizers (FC-NAc, DP-005), fragment stabilizers (TCF521-123, TCF521-129, AZ-003, AZ-008), phosphate-based inhibitors (IMP, PLP), peptide inhibitors (2a-d), as well as inhibitors from natural sources (85531185, 95911592). Additionally, this review will also include the discussions of the recent efforts by a different group of researchers for understanding the binding mechanisms of existing 14-3-3σ PPI modulators. The strategies and state-of-the-art techniques applied by various group of researchers in the discovery of a different chemical class of 14-3-3σ modulators for cancer are also briefly discussed in this review, which can be used as a guide in the development of new 14-3-3σ modulators in the near future.